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22d8ac3a MA |
1 | \input texinfo @c -*-texinfo-*- |
2 | @setfilename ../../info/dbus | |
3 | @c %**start of header | |
4 | @settitle Using of D-Bus | |
5 | @c @setchapternewpage odd | |
6 | @c %**end of header | |
7 | ||
5bd55c3c MA |
8 | @syncodeindex vr cp |
9 | @syncodeindex fn cp | |
10 | ||
22d8ac3a | 11 | @copying |
73b0cd50 | 12 | Copyright @copyright{} 2007-2011 Free Software Foundation, Inc. |
22d8ac3a MA |
13 | |
14 | @quotation | |
15 | Permission is granted to copy, distribute and/or modify this document | |
6a2c4aec | 16 | under the terms of the GNU Free Documentation License, Version 1.3 or |
22d8ac3a | 17 | any later version published by the Free Software Foundation; with no |
debf4439 GM |
18 | Invariant Sections, with the Front-Cover texts being ``A GNU Manual'', |
19 | and with the Back-Cover Texts as in (a) below. A copy of the license | |
20 | is included in the section entitled ``GNU Free Documentation License''. | |
22d8ac3a | 21 | |
6f093307 GM |
22 | (a) The FSF's Back-Cover Text is: ``You have the freedom to copy and |
23 | modify this GNU manual. Buying copies from the FSF supports it in | |
24 | developing GNU and promoting software freedom.'' | |
22d8ac3a MA |
25 | @end quotation |
26 | @end copying | |
27 | ||
28 | @dircategory Emacs | |
29 | @direntry | |
30 | * D-Bus: (dbus). Using D-Bus in Emacs. | |
31 | @end direntry | |
32 | ||
5dc584b5 | 33 | @contents |
cd71b9ae | 34 | |
977640ed | 35 | |
22d8ac3a MA |
36 | @node Top, Overview, (dir), (dir) |
37 | @top D-Bus integration in Emacs | |
38 | ||
78176e69 MA |
39 | This manual documents an API for usage of D-Bus in Emacs. D-Bus is a |
40 | message bus system, a simple way for applications to talk to one | |
41 | another. An overview of D-Bus can be found at | |
42 | @uref{http://dbus.freedesktop.org/}. | |
22d8ac3a | 43 | |
5dc584b5 | 44 | @ifnottex |
22d8ac3a | 45 | @insertcopying |
5dc584b5 | 46 | @end ifnottex |
22d8ac3a MA |
47 | |
48 | @menu | |
49 | * Overview:: An overview of D-Bus. | |
cd71b9ae | 50 | * Inspection:: Inspection of D-Bus services. |
22d8ac3a MA |
51 | * Type Conversion:: Mapping Lisp types and D-Bus types. |
52 | * Synchronous Methods:: Calling methods in a blocking way. | |
21956b56 | 53 | * Asynchronous Methods:: Calling methods non-blocking. |
addb7f2e | 54 | * Receiving Method Calls:: Offering own methods. |
22d8ac3a | 55 | * Signals:: Sending and receiving signals. |
7457f7b6 | 56 | * Alternative Buses:: Alternative buses. |
22d8ac3a | 57 | * Errors and Events:: Errors and events. |
5bd55c3c MA |
58 | * Index:: Index including concepts, functions, variables. |
59 | ||
22d8ac3a MA |
60 | * GNU Free Documentation License:: The license for this documentation. |
61 | @end menu | |
62 | ||
cd71b9ae | 63 | |
22d8ac3a MA |
64 | @node Overview |
65 | @chapter An overview of D-Bus | |
66 | @cindex overview | |
67 | ||
68 | D-Bus is an inter-process communication mechanism for applications | |
69 | residing on the same host. The communication is based on | |
70 | @dfn{messages}. Data in the messages is carried in a structured way, | |
71 | it is not just a byte stream. | |
72 | ||
73 | The communication is connection oriented to two kinds of message | |
74 | buses: a so called @dfn{system bus}, and a @dfn{session bus}. On a | |
75 | given machine, there is always one single system bus for miscellaneous | |
76 | system-wide communication, like changing of hardware configuration. | |
77 | On the other hand, the session bus is always related to a single | |
78 | user's session. | |
79 | ||
80 | Every client application, which is connected to a bus, registers under | |
81 | a @dfn{unique name} at the bus. This name is used for identifying the | |
82 | client application. Such a unique name starts always with a colon, | |
83 | and looks like @samp{:1.42}. | |
84 | ||
85 | Additionally, a client application can register itself to a so called | |
86 | @dfn{known name}, which is a series of identifiers separated by dots, | |
7ef92bc9 | 87 | as in @samp{org.gnu.Emacs}. If several applications register to the |
22d8ac3a MA |
88 | same known name, these registrations are queued, and only the first |
89 | application which has registered for the known name is reachable via | |
90 | this name. If this application disconnects from the bus, the next | |
91 | queued unique name becomes the owner of this known name. | |
92 | ||
93 | An application can install one or several objects under its name. | |
94 | Such objects are identified by an @dfn{object path}, which looks | |
95 | similar to paths in a filesystem. An example of such an object path | |
96 | could be @samp{/org/gnu/Emacs/}. | |
97 | ||
98 | Applications might send a request to an object, that means sending a | |
99 | message with some data as input parameters, and receiving a message | |
100 | from that object with the result of this message, the output | |
101 | parameters. Such a request is called @dfn{method} in D-Bus. | |
102 | ||
103 | The other form of communication are @dfn{signals}. The underlying | |
104 | message is emitted from an object and will be received by all other | |
105 | applications which have registered for such a signal. | |
106 | ||
107 | All methods and signals an object supports are called @dfn{interface} | |
108 | of the object. Interfaces are specified under a hierarchical name in | |
109 | D-Bus; an object can support several interfaces. Such an interface | |
110 | name could be @samp{org.gnu.Emacs.TextEditor} or | |
111 | @samp{org.gnu.Emacs.FileManager}. | |
112 | ||
113 | ||
114 | @node Inspection | |
cd71b9ae | 115 | @chapter Inspection of D-Bus services. |
22d8ac3a MA |
116 | @cindex inspection |
117 | ||
cd71b9ae MA |
118 | @menu |
119 | * Bus names:: Discovering D-Bus names. | |
120 | * Introspection:: Knowing the details of D-Bus services. | |
121 | * Nodes and Interfaces:: Detecting object paths and interfaces. | |
122 | * Methods and Signal:: Applying the functionality. | |
123 | * Properties and Annotations:: What else to know about interfaces. | |
124 | * Arguments and Signatures:: The final details. | |
125 | @end menu | |
126 | ||
127 | ||
128 | @node Bus names | |
129 | @section Bus names. | |
130 | ||
22d8ac3a MA |
131 | There are several basic functions which inspect the buses for |
132 | registered names. Internally they use the basic interface | |
133 | @samp{org.freedesktop.DBus}, which is supported by all objects of a bus. | |
134 | ||
135 | @defun dbus-list-activatable-names | |
22d8ac3a MA |
136 | This function returns the D-Bus service names, which can be activated. |
137 | An activatable service is described in a service registration file. | |
138 | Under GNU/Linux, such files are located at | |
139 | @file{/usr/share/dbus-1/services/}. | |
140 | ||
141 | The result is a list of strings, which is @code{nil} when there are no | |
142 | activatable service names at all. | |
143 | @end defun | |
144 | ||
145 | @defun dbus-list-names bus | |
22d8ac3a MA |
146 | All service names, which are registered at D-Bus @var{bus}, are |
147 | returned. The result is a list of strings, which is @code{nil} when | |
148 | there are no registered service names at all. Well known names are | |
149 | strings like @samp{org.freedesktop.DBus}. Names starting with | |
150 | @samp{:} are unique names for services. | |
151 | ||
152 | @var{bus} must be either the symbol @code{:system} or the symbol | |
153 | @code{:session}. | |
154 | @end defun | |
155 | ||
156 | @defun dbus-list-known-names bus | |
22d8ac3a MA |
157 | Retrieves all services which correspond to a known name in @var{bus}. |
158 | A service has a known name if it doesn't start with @samp{:}. The | |
159 | result is a list of strings, which is @code{nil} when there are no | |
160 | known names at all. | |
161 | ||
162 | @var{bus} must be either the symbol @code{:system} or the symbol | |
163 | @code{:session}. | |
164 | @end defun | |
165 | ||
166 | @defun dbus-list-queued-owners bus service | |
22d8ac3a MA |
167 | For a given service, registered at D-Bus @var{bus} under the name |
168 | @var{service}, all queued unique names are returned. The result is a | |
169 | list of strings, or @code{nil} when there are no queued names for | |
170 | @var{service} at all. | |
171 | ||
172 | @var{bus} must be either the symbol @code{:system} or the symbol | |
173 | @code{:session}. @var{service} must be a known service name as | |
174 | string. | |
175 | @end defun | |
176 | ||
177 | @defun dbus-get-name-owner bus service | |
22d8ac3a | 178 | For a given service, registered at D-Bus @var{bus} under the name |
06c0751a MA |
179 | @var{service}, the unique name of the name owner is returned. The |
180 | result is a string, or @code{nil} when there exist no name owner of | |
181 | @var{service}. | |
22d8ac3a MA |
182 | |
183 | @var{bus} must be either the symbol @code{:system} or the symbol | |
184 | @code{:session}. @var{service} must be a known service name as | |
185 | string. | |
186 | @end defun | |
187 | ||
ecd3d54f | 188 | @defun dbus-ping bus service &optional timeout |
06c0751a | 189 | Check whether the service name @var{service} is registered at D-Bus |
ecd3d54f MA |
190 | @var{bus}. @var{service} might not have been started yet, it is |
191 | autostarted if possible. The result is either @code{t} or @code{nil}. | |
06c0751a MA |
192 | |
193 | @var{bus} must be either the symbol @code{:system} or the symbol | |
ecd3d54f MA |
194 | @code{:session}. @var{service} must be a string. @var{timeout}, a |
195 | nonnegative integer, specifies the maximum number of milliseconds | |
196 | @code{dbus-ping} must return. The default value is 25,000. Example: | |
06c0751a MA |
197 | |
198 | @lisp | |
199 | (message | |
200 | "%s screensaver on board." | |
201 | (cond | |
ecd3d54f MA |
202 | ((dbus-ping :session "org.gnome.ScreenSaver" 100) "Gnome") |
203 | ((dbus-ping :session "org.freedesktop.ScreenSaver" 100) "KDE") | |
06c0751a MA |
204 | (t "No"))) |
205 | @end lisp | |
ecd3d54f MA |
206 | |
207 | If it shall be checked whether @var{service} is already running | |
208 | without autostarting it, one shall apply | |
209 | ||
210 | @lisp | |
211 | (member service (dbus-list-known-names bus)) | |
212 | @end lisp | |
06c0751a MA |
213 | @end defun |
214 | ||
22d8ac3a | 215 | @defun dbus-get-unique-name bus |
22d8ac3a MA |
216 | The unique name, under which Emacs is registered at D-Bus @var{bus}, |
217 | is returned as string. | |
218 | ||
219 | @var{bus} must be either the symbol @code{:system} or the symbol | |
220 | @code{:session}. | |
221 | @end defun | |
222 | ||
cd71b9ae MA |
223 | |
224 | @node Introspection | |
225 | @section Knowing the details of D-Bus services. | |
226 | ||
227 | D-Bus services publish their interfaces. This can be retrieved and | |
228 | analyzed during runtime, in order to understand the used | |
229 | implementation. | |
230 | ||
231 | The resulting introspection data are in XML format. The root | |
232 | introspection element is always a @code{node} element. It might have | |
233 | a @code{name} attribute, which denotes the (absolute) object path an | |
234 | interface is introspected. | |
235 | ||
236 | The root @code{node} element may have @code{node} and @code{interface} | |
237 | children. A child @code{node} element must have a @code{name} | |
238 | attribute, this case it is the relative object path to the root | |
239 | @code{node} element. | |
240 | ||
241 | An @code{interface} element has just one attribute, @code{name}, which | |
242 | is the full name of that interface. The default interface | |
243 | @samp{org.freedesktop.DBus.Introspectable} is always present. Example: | |
244 | ||
245 | @example | |
246 | <node name="/org/bluez"> | |
247 | <interface name="org.freedesktop.DBus.Introspectable"> | |
248 | @dots{} | |
249 | </interface> | |
250 | <interface name="org.bluez.Manager"> | |
251 | @dots{} | |
252 | </interface> | |
253 | <interface name="org.bluez.Database"> | |
254 | @dots{} | |
255 | </interface> | |
256 | <interface name="org.bluez.Security"> | |
257 | @dots{} | |
258 | </interface> | |
259 | <node name="service_audio"/> | |
260 | <node name="service_input"/> | |
261 | <node name="service_network"/> | |
262 | <node name="service_serial"/> | |
263 | </node> | |
264 | @end example | |
265 | ||
266 | Children of an @code{interface} element can be @code{method}, | |
267 | @code{signal} and @code{property} elements. A @code{method} element | |
268 | stands for a D-Bus method of the surrounding interface. The element | |
269 | itself has a @code{name} attribute, showing the method name. Children | |
270 | elements @code{arg} stand for the arguments of a method. Example: | |
271 | ||
272 | @example | |
273 | <method name="ResolveHostName"> | |
274 | <arg name="interface" type="i" direction="in"/> | |
275 | <arg name="protocol" type="i" direction="in"/> | |
276 | <arg name="name" type="s" direction="in"/> | |
277 | <arg name="aprotocol" type="i" direction="in"/> | |
278 | <arg name="flags" type="u" direction="in"/> | |
279 | <arg name="interface" type="i" direction="out"/> | |
280 | <arg name="protocol" type="i" direction="out"/> | |
281 | <arg name="name" type="s" direction="out"/> | |
282 | <arg name="aprotocol" type="i" direction="out"/> | |
283 | <arg name="address" type="s" direction="out"/> | |
284 | <arg name="flags" type="u" direction="out"/> | |
285 | </method> | |
286 | @end example | |
287 | ||
288 | @code{arg} elements can have the attributes @code{name}, @code{type} | |
289 | and @code{direction}. The @code{name} attribute is optional. The | |
290 | @code{type} attribute stands for the @dfn{signature} of the argument | |
291 | in D-Bus. For a discussion of D-Bus types and their Lisp | |
292 | representation see @ref{Type Conversion}.@footnote{D-Bus signatures | |
293 | are explained in the D-Bus specification | |
294 | @uref{http://dbus.freedesktop.org/doc/dbus-specification.html#message-protocol-signatures}.} | |
295 | The @code{direction} attribute of an @code{arg} element can be only | |
296 | @samp{in} or @samp{out}; in case it is omitted, it defaults to | |
297 | @samp{in}. | |
298 | ||
299 | A @code{signal} element of an @code{interface} has a similar | |
300 | structure. The @code{direction} attribute of an @code{arg} child | |
301 | element can be only @samp{out} here; which is also the default value. | |
302 | Example: | |
303 | ||
304 | @example | |
305 | <signal name="StateChanged"> | |
306 | <arg name="state" type="i"/> | |
307 | <arg name="error" type="s"/> | |
308 | </signal> | |
309 | @end example | |
310 | ||
311 | A @code{property} element has no @code{arg} child | |
312 | element. It just has the attributes @code{name}, @code{type} and | |
313 | @code{access}, which are all mandatory. The @code{access} attribute | |
314 | allows the values @samp{readwrite}, @samp{read}, and @samp{write}. | |
315 | Example: | |
316 | ||
317 | @example | |
318 | <property name="Status" type="u" direction="read"/> | |
319 | @end example | |
320 | ||
321 | @code{annotation} elements can be children of @code{interface}, | |
322 | @code{method}, @code{signal}, and @code{property} elements. Unlike | |
323 | properties, which can change their values during lifetime of a D-Bus | |
324 | object, annotations are static. Often they are used for code | |
325 | generators of D-Bus langugae bindings. Example: | |
326 | ||
327 | @example | |
328 | <annotation name="de.berlios.Pinot.GetStatistics" value="pinotDBus"/> | |
329 | @end example | |
330 | ||
331 | Annotations have just @code{name} and @code{value} attributes, both | |
332 | must be strings. | |
333 | ||
22d8ac3a | 334 | @defun dbus-introspect bus service path |
cd71b9ae MA |
335 | This function returns all interfaces and sub-nodes of @var{service}, |
336 | registered at object path @var{path} at bus @var{bus}. | |
22d8ac3a MA |
337 | |
338 | @var{bus} must be either the symbol @code{:system} or the symbol | |
339 | @code{:session}. @var{service} must be a known service name, and | |
340 | @var{path} must be a valid object path. The last two parameters are | |
341 | strings. The result, the introspection data, is a string in XML | |
cd71b9ae | 342 | format. Example: |
22d8ac3a | 343 | |
06c0751a | 344 | @lisp |
22d8ac3a MA |
345 | (dbus-introspect |
346 | :system "org.freedesktop.Hal" | |
347 | "/org/freedesktop/Hal/devices/computer") | |
348 | ||
d9e21158 | 349 | @result{} "<!DOCTYPE node PUBLIC |
cd71b9ae MA |
350 | "-//freedesktop//DTD D-BUS Object Introspection 1.0//EN" |
351 | "http://www.freedesktop.org/standards/dbus/1.0/introspect.dtd"> | |
d9e21158 | 352 | <node> |
cd71b9ae MA |
353 | <interface name="org.freedesktop.Hal.Device"> |
354 | <method name="GetAllProperties"> | |
355 | <arg name="properties" direction="out" type="a@{sv@}"/> | |
d9e21158 | 356 | </method> |
c9ecb5a7 | 357 | @dots{} |
cd71b9ae MA |
358 | <signal name="PropertyModified"> |
359 | <arg name="num_updates" type="i"/> | |
360 | <arg name="updates" type="a(sbb)"/> | |
d9e21158 MA |
361 | </signal> |
362 | </interface> | |
c9ecb5a7 | 363 | @dots{} |
d9e21158 | 364 | </node>" |
06c0751a | 365 | @end lisp |
22d8ac3a | 366 | |
cd71b9ae MA |
367 | This example informs us, that the service @samp{org.freedesktop.Hal} |
368 | at object path @samp{/org/freedesktop/Hal/devices/computer} offers the | |
369 | interface @samp{org.freedesktop.Hal.Device} (and 2 other interfaces | |
22d8ac3a | 370 | not documented here). This interface contains the method |
cd71b9ae | 371 | @samp{GetAllProperties}, which needs no input parameters, but returns |
22d8ac3a MA |
372 | as output parameter an array of dictionary entries (key-value pairs). |
373 | Every dictionary entry has a string as key, and a variant as value. | |
374 | ||
375 | The interface offers also a signal, which returns 2 parameters: an | |
376 | integer, and an array consisting of elements which are a struct of a | |
cd71b9ae MA |
377 | string and 2 boolean values.@footnote{ The interfaces of the service |
378 | @samp{org.freedesktop.Hal} are described at | |
22d8ac3a MA |
379 | @uref{http://people.freedesktop.org/~david/hal-spec/hal-spec.html#interfaces}.} |
380 | @end defun | |
381 | ||
cd71b9ae MA |
382 | @defun dbus-introspect-xml bus service path |
383 | This function has the same intention as function | |
384 | @code{dbus-introspect}. The returned value is a parsed XML tree, | |
385 | which can be used for further analysis. Example: | |
386 | ||
387 | @lisp | |
388 | (dbus-introspect-xml | |
389 | :session "org.freedesktop.xesam.searcher" | |
390 | "/org/freedesktop/xesam/searcher/main") | |
391 | ||
392 | @result{} (node ((name . "/org/freedesktop/xesam/searcher/main")) | |
393 | (interface ((name . "org.freedesktop.xesam.Search")) | |
394 | (method ((name . "GetHitData")) | |
395 | (arg ((name . "search") (type . "s") (direction . "in"))) | |
396 | (arg ((name . "hit_ids") (type . "au") (direction . "in"))) | |
397 | (arg ((name . "fields") (type . "as") (direction . "in"))) | |
398 | (arg ((name . "hit_data") (type . "aav") (direction . "out"))) | |
399 | ) | |
400 | @dots{} | |
401 | (signal ((name . "HitsAdded")) | |
402 | (arg ((name . "search") (type . "s"))) | |
403 | (arg ((name . "count") (type . "u"))) | |
404 | ) | |
405 | ) | |
406 | @dots{} | |
407 | ) | |
408 | @end lisp | |
409 | @end defun | |
410 | ||
411 | @defun dbus-introspect-get-attribute object attribute | |
412 | It returns the @var{attribute} value of a D-Bus introspection | |
413 | @var{object}. @var{object} can be every subtree of a parsed XML tree | |
414 | as retrieved with @code{dbus-introspect-xml}. @var{attribute} must be | |
415 | a string according to the attribute names in the D-Bus specification. | |
416 | Example: | |
417 | ||
418 | @lisp | |
419 | (dbus-introspect-get-attribute | |
420 | (dbus-introspect-xml :system "org.freedesktop.SystemToolsBackends" | |
421 | "/org/freedesktop/SystemToolsBackends/UsersConfig") | |
422 | "name") | |
423 | ||
424 | @result{} "/org/freedesktop/SystemToolsBackends/UsersConfig" | |
425 | @end lisp | |
426 | ||
5bd55c3c MA |
427 | If @var{object} has no @var{attribute}, the function returns |
428 | @code{nil}. | |
cd71b9ae MA |
429 | @end defun |
430 | ||
431 | ||
432 | @node Nodes and Interfaces | |
433 | @section Detecting object paths and interfaces. | |
434 | ||
435 | The first elements, to be introspected for a D-Bus object, are further | |
436 | object paths and interfaces. | |
437 | ||
438 | @defun dbus-introspect-get-node-names bus service path | |
439 | All node names of @var{service} in D-Bus @var{bus} at object path | |
440 | @var{path} are returned as list of strings. Example: | |
441 | ||
442 | @lisp | |
443 | (dbus-introspect-get-node-names | |
444 | :session "org.gnome.seahorse" "/org/gnome/seahorse") | |
445 | ||
446 | @result{} ("crypto" "keys") | |
447 | @end lisp | |
448 | ||
449 | The node names stand for further object paths of the D-Bus | |
450 | @var{service}, relative to @var{path}. In the example, | |
451 | @samp{/org/gnome/seahorse/crypto} and @samp{/org/gnome/seahorse/keys} | |
452 | are also object paths of the D-Bus service @samp{org.gnome.seahorse}. | |
453 | @end defun | |
454 | ||
455 | @defun dbus-introspect-get-all-nodes bus service path | |
456 | This function returns all node names of @var{service} in D-Bus | |
457 | @var{bus} at object path @var{path}. It returns a list of strings | |
458 | with all object paths of @var{service}, starting at @var{path}. | |
459 | Example: | |
460 | ||
461 | @lisp | |
462 | (dbus-introspect-get-all-nodes :session "org.gnome.seahorse" "/") | |
463 | ||
464 | @result{} ("/" "/org" "/org/gnome" "/org/gnome/seahorse" | |
465 | "/org/gnome/seahorse/crypto" | |
466 | "/org/gnome/seahorse/keys" | |
467 | "/org/gnome/seahorse/keys/openpgp" | |
468 | "/org/gnome/seahorse/keys/openpgp/local" | |
469 | "/org/gnome/seahorse/keys/openssh" | |
470 | "/org/gnome/seahorse/keys/openssh/local") | |
471 | @end lisp | |
472 | @end defun | |
473 | ||
474 | @defun dbus-introspect-get-interface-names bus service path | |
475 | There will be returned a list strings of all interface names of | |
476 | @var{service} in D-Bus @var{bus} at object path @var{path}. This list | |
477 | will contain the default interface @samp{org.freedesktop.DBus.Introspectable}. | |
478 | ||
479 | Another default interface is @samp{org.freedesktop.DBus.Properties}. | |
480 | If present, @code{interface} elements can also have @code{property} | |
481 | children. Example: | |
482 | ||
483 | @lisp | |
484 | (dbus-introspect-get-interface-names | |
485 | :system "org.freedesktop.Hal" | |
486 | "/org/freedesktop/Hal/devices/computer") | |
487 | ||
488 | @result{} ("org.freedesktop.DBus.Introspectable" | |
489 | "org.freedesktop.Hal.Device" | |
490 | "org.freedesktop.Hal.Device.SystemPowerManagement" | |
491 | "org.freedesktop.Hal.Device.CPUFreq") | |
492 | @end lisp | |
493 | @end defun | |
494 | ||
495 | @defun dbus-introspect-get-interface bus service path interface | |
496 | Return @var{interface} of @var{service} in D-Bus @var{bus} at object | |
497 | path @var{path}. The return value is an XML element. @var{interface} | |
498 | must be a string, element of the list returned by | |
499 | @code{dbus-introspect-get-interface-names}. Example: | |
500 | ||
501 | @lisp | |
502 | (dbus-introspect-get-interface | |
503 | :session "org.freedesktop.xesam.searcher" | |
504 | "/org/freedesktop/xesam/searcher/main" | |
505 | "org.freedesktop.xesam.Search") | |
506 | ||
507 | @result{} (interface ((name . "org.freedesktop.xesam.Search")) | |
508 | (method ((name . "GetHitData")) | |
509 | (arg ((name . "search") (type . "s") (direction . "in"))) | |
510 | (arg ((name . "hit_ids") (type . "au") (direction . "in"))) | |
511 | (arg ((name . "fields") (type . "as") (direction . "in"))) | |
512 | (arg ((name . "hit_data") (type . "aav") (direction . "out"))) | |
513 | ) | |
514 | @dots{} | |
515 | (signal ((name . "HitsAdded")) | |
516 | (arg ((name . "search") (type . "s"))) | |
517 | (arg ((name . "count") (type . "u"))) | |
518 | ) | |
519 | ) | |
520 | @end lisp | |
521 | @end defun | |
522 | ||
523 | @noindent | |
524 | With these functions, it is possible to retrieve all introspection | |
525 | data from a running system: | |
526 | ||
527 | @lisp | |
528 | (with-current-buffer (switch-to-buffer "*introspect*") | |
529 | (erase-buffer) | |
530 | (dolist (service (dbus-list-known-names :session)) | |
531 | (dolist (path (dbus-introspect-get-all-nodes :session service "/")) | |
532 | ;; We want to introspect only elements, which have more than | |
533 | ;; the default interface "org.freedesktop.DBus.Introspectable". | |
534 | (when (delete | |
535 | "org.freedesktop.DBus.Introspectable" | |
536 | (dbus-introspect-get-interface-names :session service path)) | |
537 | (insert (message "\nservice: \"%s\" path: \"%s\"\n" service path) | |
538 | (dbus-introspect :session service path)) | |
539 | (redisplay t))))) | |
540 | @end lisp | |
541 | ||
542 | ||
543 | @node Methods and Signal | |
544 | @section Applying the functionality. | |
545 | ||
546 | Methods and signals are the communicatione means to D-Bus. The | |
547 | following functions return their specifications. | |
548 | ||
549 | @defun dbus-introspect-get-method-names bus service path interface | |
550 | Return a list of strings of all method names of @var{interface} of | |
551 | @var{service} in D-Bus @var{bus} at object path @var{path}. Example: | |
552 | ||
553 | @lisp | |
554 | (dbus-introspect-get-method-names | |
555 | :session "org.freedesktop.xesam.searcher" | |
556 | "/org/freedesktop/xesam/searcher/main" | |
557 | "org.freedesktop.xesam.Search") | |
558 | ||
559 | @result{} ("GetState" "StartSearch" "GetHitCount" "GetHits" "NewSession" | |
560 | "CloseSession" "GetHitData" "SetProperty" "NewSearch" | |
561 | "GetProperty" "CloseSearch") | |
562 | @end lisp | |
563 | @end defun | |
564 | ||
565 | @defun dbus-introspect-get-method bus service path interface method | |
566 | This function returns @var{method} of @var{interface} as XML element. | |
567 | It must be located at @var{service} in D-Bus @var{bus} at object path | |
568 | @var{path}. @var{method} must be a string, element of the list | |
569 | returned by @code{dbus-introspect-get-method-names}. Example: | |
570 | ||
571 | @lisp | |
572 | (dbus-introspect-get-method | |
573 | :session "org.freedesktop.xesam.searcher" | |
574 | "/org/freedesktop/xesam/searcher/main" | |
575 | "org.freedesktop.xesam.Search" "GetHitData") | |
576 | ||
577 | @result{} (method ((name . "GetHitData")) | |
578 | (arg ((name . "search") (type . "s") (direction . "in"))) | |
579 | (arg ((name . "hit_ids") (type . "au") (direction . "in"))) | |
580 | (arg ((name . "fields") (type . "as") (direction . "in"))) | |
581 | (arg ((name . "hit_data") (type . "aav") (direction . "out"))) | |
582 | ) | |
583 | @end lisp | |
584 | @end defun | |
585 | ||
586 | @defun dbus-introspect-get-signal-names bus service path interface | |
587 | Return a list of strings of all signal names of @var{interface} of | |
588 | @var{service} in D-Bus @var{bus} at object path @var{path}. Example: | |
589 | ||
590 | @lisp | |
591 | (dbus-introspect-get-signal-names | |
592 | :session "org.freedesktop.xesam.searcher" | |
593 | "/org/freedesktop/xesam/searcher/main" | |
594 | "org.freedesktop.xesam.Search") | |
595 | ||
596 | @result{} ("StateChanged" "SearchDone" "HitsModified" | |
597 | "HitsRemoved" "HitsAdded") | |
598 | @end lisp | |
599 | @end defun | |
600 | ||
601 | @defun dbus-introspect-get-signal bus service path interface signal | |
602 | This function returns @var{signal} of @var{interface} as XML element. | |
603 | It must be located at @var{service} in D-Bus @var{bus} at object path | |
604 | @var{path}. @var{signal} must be a string, element of the list | |
605 | returned by @code{dbus-introspect-get-signal-names}. Example: | |
606 | ||
607 | @lisp | |
608 | (dbus-introspect-get-signal | |
609 | :session "org.freedesktop.xesam.searcher" | |
610 | "/org/freedesktop/xesam/searcher/main" | |
611 | "org.freedesktop.xesam.Search" "HitsAdded") | |
612 | ||
613 | @result{} (signal ((name . "HitsAdded")) | |
614 | (arg ((name . "search") (type . "s"))) | |
615 | (arg ((name . "count") (type . "u"))) | |
616 | ) | |
617 | @end lisp | |
618 | @end defun | |
619 | ||
620 | ||
621 | @node Properties and Annotations | |
622 | @section What else to know about interfaces. | |
623 | ||
624 | Interfaces can have properties. These can be exposed via the | |
625 | @samp{org.freedesktop.DBus.Properties} interface@footnote{See | |
626 | @uref{http://dbus.freedesktop.org/doc/dbus-specification.html#standard-interfaces-properties}}. | |
627 | That is, properties can be retrieved and changed during lifetime of an | |
628 | element. | |
629 | ||
630 | Annotations, on the other hand, are static values for an element. | |
631 | Often, they are used to instruct generators, how to generate code from | |
632 | the interface for a given language binding. | |
633 | ||
634 | @defun dbus-introspect-get-property-names bus service path interface | |
635 | Return a list of strings with all property names of @var{interface} of | |
636 | @var{service} in D-Bus @var{bus} at object path @var{path}. Example: | |
637 | ||
638 | @lisp | |
639 | (dbus-introspect-get-property-names | |
640 | :session "org.kde.kded" "/modules/networkstatus" | |
641 | "org.kde.Solid.Networking.Client") | |
642 | ||
643 | @result{} ("Status") | |
644 | @end lisp | |
645 | ||
646 | If an interface declares properties, the corresponding element supports | |
647 | also the @samp{org.freedesktop.DBus.Properties} interface. | |
648 | @end defun | |
649 | ||
650 | @defun dbus-introspect-get-property bus service path interface property | |
651 | This function returns @var{property} of @var{interface} as XML element. | |
652 | It must be located at @var{service} in D-Bus @var{bus} at object path | |
653 | @var{path}. @var{property} must be a string, element of the list | |
654 | returned by @code{dbus-introspect-get-property-names}. | |
655 | ||
656 | A @var{property} value can be retrieved by the function | |
657 | @code{dbus-introspect-get-attribute}. Example: | |
658 | ||
659 | @lisp | |
660 | (dbus-introspect-get-property | |
661 | :session "org.kde.kded" "/modules/networkstatus" | |
662 | "org.kde.Solid.Networking.Client" "Status") | |
663 | ||
664 | @result{} (property ((access . "read") (type . "u") (name . "Status"))) | |
665 | ||
666 | (dbus-introspect-get-attribute | |
667 | (dbus-introspect-get-property | |
668 | :session "org.kde.kded" "/modules/networkstatus" | |
669 | "org.kde.Solid.Networking.Client" "Status") | |
670 | "access") | |
671 | ||
672 | @result{} "read" | |
673 | @end lisp | |
674 | @end defun | |
675 | ||
676 | @defun dbus-get-property bus service path interface property | |
677 | This function returns the value of @var{property} of @var{interface}. | |
678 | It will be checked at @var{bus}, @var{service}, @var{path}. The | |
5bd55c3c | 679 | result can be any valid D-Bus value, or @code{nil} if there is no |
cd71b9ae MA |
680 | @var{property}. Example: |
681 | ||
682 | @lisp | |
683 | (dbus-get-property | |
684 | :session "org.kde.kded" "/modules/networkstatus" | |
685 | "org.kde.Solid.Networking.Client" "Status") | |
686 | ||
687 | @result{} 4 | |
688 | @end lisp | |
689 | @end defun | |
690 | ||
691 | @defun dbus-set-property bus service path interface property value | |
692 | Set value of @var{property} of @var{interface} to @var{value}. It | |
693 | will be checked at @var{bus}, @var{service}, @var{path}. When the | |
694 | value has been set successful, the result is @var{value}. Otherwise, | |
695 | @code{nil} is returned. Example: | |
696 | ||
697 | @lisp | |
698 | (dbus-set-property | |
699 | :session "org.kde.kaccess" "/MainApplication" | |
700 | "com.trolltech.Qt.QApplication" "doubleClickInterval" 500) | |
701 | ||
702 | @result{} 500 | |
703 | @end lisp | |
704 | @end defun | |
705 | ||
706 | @defun dbus-get-all-properties bus service path interface | |
707 | This function returns all properties of @var{interface}. It will be | |
708 | checked at @var{bus}, @var{service}, @var{path}. The result is a list | |
709 | of cons. Every cons contains the name of the property, and its value. | |
710 | If there are no properties, @code{nil} is returned. Example: | |
711 | ||
712 | @lisp | |
713 | (dbus-get-all-properties | |
714 | :session "org.kde.kaccess" "/MainApplication" | |
715 | "com.trolltech.Qt.QApplication") | |
716 | ||
717 | @result{} (("cursorFlashTime" . 1000) ("doubleClickInterval" . 500) | |
718 | ("keyboardInputInterval" . 400) ("wheelScrollLines" . 3) | |
719 | ("globalStrut" 0 0) ("startDragTime" . 500) | |
720 | ("startDragDistance" . 4) ("quitOnLastWindowClosed" . t) | |
721 | ("styleSheet" . "")) | |
722 | @end lisp | |
723 | @end defun | |
724 | ||
725 | @defun dbus-introspect-get-annotation-names bus service path interface &optional name | |
726 | Return a list of all annotation names as list of strings. If | |
727 | @var{name} is @code{nil}, the annotations are children of | |
728 | @var{interface}, otherwise @var{name} must be a @code{method}, | |
729 | @code{signal}, or @code{property} XML element, where the annotations | |
730 | belong to. Example: | |
731 | ||
732 | @lisp | |
733 | (dbus-introspect-get-annotation-names | |
734 | :session "de.berlios.Pinot" "/de/berlios/Pinot" | |
735 | "de.berlios.Pinot" "GetStatistics") | |
736 | ||
737 | @result{} ("de.berlios.Pinot.GetStatistics") | |
738 | @end lisp | |
739 | ||
740 | Default annotation names@footnote{See | |
741 | @uref{http://dbus.freedesktop.org/doc/dbus-specification.html#introspection-format}} | |
742 | are | |
743 | ||
744 | @table @samp | |
745 | @item org.freedesktop.DBus.Deprecated | |
746 | Whether or not the entity is deprecated; defaults to @code{nil} | |
747 | ||
748 | @item org.freedesktop.DBus.GLib.CSymbol | |
749 | The C symbol; may be used for @code{methods} and @code{interfaces} | |
750 | ||
751 | @item org.freedesktop.DBus.Method.NoReply | |
752 | If set, don't expect a reply to the @code{method} call; defaults to @code{nil} | |
753 | @end table | |
754 | @end defun | |
755 | ||
756 | @defun dbus-introspect-get-annotation bus service path interface name annotation | |
757 | Return annotation @var{ANNOTATION} as XML object. If @var{name} is | |
758 | @code{nil}, @var{ANNOTATION} is a child of @var{interface}, otherwise | |
759 | @var{name} must be the name of a @code{method}, @code{signal}, or | |
760 | @code{property} XML element, where the @var{ANNOTATION} belongs to. | |
761 | ||
762 | An attribute value can be retrieved by | |
763 | @code{dbus-introspect-get-attribute}. Example: | |
764 | ||
765 | @lisp | |
766 | (dbus-introspect-get-annotation | |
767 | :session "de.berlios.Pinot" "/de/berlios/Pinot" | |
768 | "de.berlios.Pinot" "GetStatistics" | |
769 | "de.berlios.Pinot.GetStatistics") | |
770 | ||
771 | @result{} (annotation ((name . "de.berlios.Pinot.GetStatistics") | |
772 | (value . "pinotDBus"))) | |
773 | ||
774 | (dbus-introspect-get-attribute | |
775 | (dbus-introspect-get-annotation | |
776 | :session "de.berlios.Pinot" "/de/berlios/Pinot" | |
777 | "de.berlios.Pinot" "GetStatistics" | |
778 | "de.berlios.Pinot.GetStatistics") | |
779 | "value") | |
780 | ||
781 | @result{} "pinotDBus" | |
782 | @end lisp | |
783 | @end defun | |
784 | ||
785 | ||
786 | @node Arguments and Signatures | |
787 | @section The final details. | |
788 | ||
789 | Methods and signals have arguments. They are described in the | |
790 | @code{arg} XML elements. | |
791 | ||
792 | @defun dbus-introspect-get-argument-names bus service path interface name | |
793 | Return a list of all argument names as list of strings. @var{name} | |
794 | must be a @code{method} or @code{signal} XML element. Example: | |
795 | ||
796 | @lisp | |
797 | (dbus-introspect-get-argument-names | |
798 | :session "org.freedesktop.xesam.searcher" | |
799 | "/org/freedesktop/xesam/searcher/main" | |
800 | "org.freedesktop.xesam.Search" "GetHitData") | |
801 | ||
802 | @result{} ("search" "hit_ids" "fields" "hit_data") | |
803 | @end lisp | |
804 | ||
805 | Argument names are optional; the function can return @code{nil} | |
806 | therefore, even if the method or signal has arguments. | |
807 | @end defun | |
808 | ||
809 | @defun dbus-introspect-get-argument bus service path interface name arg | |
810 | Return argument @var{ARG} as XML object. @var{name} | |
811 | must be a @code{method} or @code{signal} XML element. Example: | |
812 | ||
813 | @lisp | |
814 | (dbus-introspect-get-argument | |
815 | :session "org.freedesktop.xesam.searcher" | |
816 | "/org/freedesktop/xesam/searcher/main" | |
817 | "org.freedesktop.xesam.Search" "GetHitData" "search") | |
818 | ||
819 | @result{} (arg ((name . "search") (type . "s") (direction . "in"))) | |
820 | @end lisp | |
821 | @end defun | |
822 | ||
823 | @defun dbus-introspect-get-signature bus service path interface name &optional direction | |
824 | Return signature of a @code{method} or @code{signal}, represented by | |
825 | @var{name}, as string. | |
826 | ||
827 | If @var{name} is a @code{method}, @var{direction} can be either | |
828 | @samp{in} or @samp{out}. If @var{direction} is @code{nil}, @samp{in} | |
829 | is assumed. | |
830 | ||
831 | If @var{name} is a @code{signal}, and @var{direction} is | |
832 | non-@code{nil}, @var{direction} must be @samp{out}. Example: | |
833 | ||
834 | @lisp | |
835 | (dbus-introspect-get-signature | |
836 | :session "org.freedesktop.xesam.searcher" | |
837 | "/org/freedesktop/xesam/searcher/main" | |
838 | "org.freedesktop.xesam.Search" "GetHitData" "in") | |
839 | ||
840 | @result{} "sauas" | |
841 | ||
842 | (dbus-introspect-get-signature | |
843 | :session "org.freedesktop.xesam.searcher" | |
844 | "/org/freedesktop/xesam/searcher/main" | |
845 | "org.freedesktop.xesam.Search" "HitsAdded") | |
846 | ||
21956b56 | 847 | @result{} "su" |
cd71b9ae MA |
848 | @end lisp |
849 | @end defun | |
850 | ||
22d8ac3a MA |
851 | |
852 | @node Type Conversion | |
853 | @chapter Mapping Lisp types and D-Bus types. | |
854 | @cindex type conversion | |
855 | ||
856 | D-Bus method calls and signals accept usually several arguments as | |
857 | parameters, either as input parameter, or as output parameter. Every | |
858 | argument belongs to a D-Bus type. | |
859 | ||
6a31c819 | 860 | Such arguments must be mapped between the value encoded as a D-Bus |
22d8ac3a MA |
861 | type, and the corresponding type of Lisp objects. The mapping is |
862 | applied Lisp object @expansion{} D-Bus type for input parameters, and | |
863 | D-Bus type @expansion{} Lisp object for output parameters. | |
864 | ||
865 | ||
866 | @section Input parameters. | |
867 | ||
868 | Input parameters for D-Bus methods and signals occur as arguments of a | |
6a31c819 | 869 | Lisp function call. The following mapping to D-Bus types is |
22d8ac3a MA |
870 | applied, when the corresponding D-Bus message is created: |
871 | ||
872 | @example | |
5bd55c3c | 873 | @multitable {negative integer} {@expansion{}} {DBUS_TYPE_BOOLEAN} |
22d8ac3a MA |
874 | @item Lisp type @tab @tab D-Bus type |
875 | @item | |
876 | @item @code{t} and @code{nil} @tab @expansion{} @tab DBUS_TYPE_BOOLEAN | |
5bd55c3c MA |
877 | @item natural number @tab @expansion{} @tab DBUS_TYPE_UINT32 |
878 | @item negative integer @tab @expansion{} @tab DBUS_TYPE_INT32 | |
22d8ac3a MA |
879 | @item float @tab @expansion{} @tab DBUS_TYPE_DOUBLE |
880 | @item string @tab @expansion{} @tab DBUS_TYPE_STRING | |
6a31c819 | 881 | @item list @tab @expansion{} @tab DBUS_TYPE_ARRAY |
22d8ac3a MA |
882 | @end multitable |
883 | @end example | |
884 | ||
6a31c819 MA |
885 | Other Lisp objects, like symbols or hash tables, are not accepted as |
886 | input parameter. | |
887 | ||
888 | If it is necessary to use another D-Bus type, a corresponding type | |
889 | symbol can be preceeded to the corresponding Lisp object. Basic D-Bus | |
d4e67bc5 MA |
890 | types are represented by the type symbols @code{:byte}, |
891 | @code{:boolean}, @code{:int16}, @code{:uint16}, @code{:int32}, | |
892 | @code{:uint32}, @code{:int64}, @code{:uint64}, @code{:double}, | |
6f8fc60c MA |
893 | @code{:string}, @code{:object-path}, @code{:signature} and |
894 | @code{:unix-fd}. | |
6a31c819 | 895 | |
22d8ac3a | 896 | @noindent |
6a31c819 MA |
897 | Example: |
898 | ||
899 | @lisp | |
5bd55c3c | 900 | (dbus-call-method @dots{} @var{NAT-NUMBER} @var{STRING}) |
6a31c819 MA |
901 | @end lisp |
902 | ||
903 | is equivalent to | |
904 | ||
905 | @lisp | |
5bd55c3c | 906 | (dbus-call-method @dots{} :uint32 @var{NAT-NUMBER} :string @var{STRING}) |
6a31c819 MA |
907 | @end lisp |
908 | ||
909 | but different to | |
910 | ||
911 | @lisp | |
5bd55c3c | 912 | (dbus-call-method @dots{} :int32 @var{NAT-NUMBER} :signature @var{STRING}) |
6a31c819 MA |
913 | @end lisp |
914 | ||
4db2806c MA |
915 | The value for a byte D-Bus type can be any integer in the range 0 |
916 | through 255. If a character is used as argument, modifiers | |
917 | represented outside this range are stripped of. For example, | |
918 | @code{:byte ?x} is equal to @code{:byte ?\M-x}, but it is not equal to | |
919 | @code{:byte ?\C-x} or @code{:byte ?\M-\C-x}. | |
c9ecb5a7 | 920 | |
4db2806c MA |
921 | A D-Bus compound type is always represented as a list. The @sc{car} |
922 | of this list can be the type symbol @code{:array}, @code{:variant}, | |
d4e67bc5 MA |
923 | @code{:struct} or @code{:dict-entry}, which would result in a |
924 | corresponding D-Bus container. @code{:array} is optional, because | |
4db2806c | 925 | this is the default compound D-Bus type for a list. |
6a31c819 MA |
926 | |
927 | The objects being elements of the list are checked according to the | |
928 | D-Bus compound type rules. | |
929 | ||
930 | @itemize | |
4db2806c MA |
931 | @item An array must contain only elements of the same D-Bus type. It |
932 | can be empty. | |
933 | ||
6a31c819 | 934 | @item A variant must contain only one single element. |
4db2806c | 935 | |
6a31c819 | 936 | @item A dictionary entry must be element of an array, and it must |
4db2806c MA |
937 | contain only a key-value pair of two elements, with a basic D-Bus type |
938 | key. | |
939 | ||
6a31c819 MA |
940 | @item There is no restriction for structs. |
941 | @end itemize | |
942 | ||
4db2806c MA |
943 | If an empty array needs an element D-Bus type other than string, it |
944 | can contain exactly one element of D-Bus type @code{:signature}. The | |
945 | value of this element (a string) is used as the signature of the | |
946 | elements of this array. Example: | |
6a31c819 MA |
947 | |
948 | @lisp | |
4db2806c MA |
949 | (dbus-call-method |
950 | :session "org.freedesktop.Notifications" | |
951 | "/org/freedesktop/Notifications" | |
952 | "org.freedesktop.Notifications" "Notify" | |
953 | "GNU Emacs" ;; Application name. | |
954 | 0 ;; No replacement of other notifications. | |
955 | "" ;; No icon. | |
956 | "Notification summary" ;; Summary. | |
957 | (format ;; Body. | |
958 | "This is a test notification, raised from %s" (emacs-version)) | |
959 | '(:array) ;; No actions (empty array of strings). | |
960 | '(:array :signature "@{sv@}") ;; No hints | |
961 | ;; (empty array of dictionary entries). | |
0ecd3c90 | 962 | :int32 -1) ;; Default timeout. |
4db2806c MA |
963 | |
964 | @result{} 3 | |
6a31c819 | 965 | @end lisp |
22d8ac3a | 966 | |
ace706d1 MA |
967 | @defun dbus-string-to-byte-array string |
968 | Sometimes, D-Bus methods require as input parameter an array of bytes, | |
969 | instead of a string. If it is guaranteed, that @var{string} is an | |
970 | UTF8 string, this function performs the conversion. Example: | |
971 | ||
972 | @lisp | |
973 | (dbus-string-to-byte-array "/etc/hosts") | |
974 | ||
975 | @result{} (:array :byte 47 :byte 101 :byte 116 :byte 99 :byte 47 | |
976 | :byte 104 :byte 111 :byte 115 :byte 116 :byte 115) | |
977 | @end lisp | |
978 | @end defun | |
979 | ||
980 | @defun dbus-escape-as-identifier string | |
981 | Escape an arbitrary @var{string} so it follows the rules for a C | |
982 | identifier. The escaped string can be used as object path component, | |
983 | interface element component, bus name component or member name in | |
984 | D-Bus. | |
985 | ||
986 | The escaping consists of replacing all non-alphanumerics, and the | |
987 | first character if it's a digit, with an underscore and two | |
988 | lower-case hex digits. As a special case, "" is escaped to | |
989 | "_". Example: | |
990 | ||
991 | @lisp | |
992 | (dbus-escape-as-identifier "0123abc_xyz\x01\xff") | |
993 | ||
994 | @result{} "_30123abc_5fxyz_01_ff" | |
995 | @end lisp | |
996 | @end defun | |
997 | ||
22d8ac3a MA |
998 | |
999 | @section Output parameters. | |
1000 | ||
1001 | Output parameters of D-Bus methods and signals are mapped to Lisp | |
6a31c819 | 1002 | objects. |
22d8ac3a MA |
1003 | |
1004 | @example | |
5bd55c3c | 1005 | @multitable {DBUS_TYPE_OBJECT_PATH} {@expansion{}} {natural number or float} |
22d8ac3a MA |
1006 | @item D-Bus type @tab @tab Lisp type |
1007 | @item | |
1008 | @item DBUS_TYPE_BOOLEAN @tab @expansion{} @tab @code{t} or @code{nil} | |
5bd55c3c MA |
1009 | @item DBUS_TYPE_BYTE @tab @expansion{} @tab natural number |
1010 | @item DBUS_TYPE_UINT16 @tab @expansion{} @tab natural number | |
1011 | @item DBUS_TYPE_INT16 @tab @expansion{} @tab integer | |
1012 | @item DBUS_TYPE_UINT32 @tab @expansion{} @tab natural number or float | |
6f8fc60c | 1013 | @item DBUS_TYPE_UNIX_FD @tab @expansion{} @tab natural number or float |
5bd55c3c MA |
1014 | @item DBUS_TYPE_INT32 @tab @expansion{} @tab integer or float |
1015 | @item DBUS_TYPE_UINT64 @tab @expansion{} @tab natural number or float | |
1016 | @item DBUS_TYPE_INT64 @tab @expansion{} @tab integer or float | |
22d8ac3a MA |
1017 | @item DBUS_TYPE_DOUBLE @tab @expansion{} @tab float |
1018 | @item DBUS_TYPE_STRING @tab @expansion{} @tab string | |
1019 | @item DBUS_TYPE_OBJECT_PATH @tab @expansion{} @tab string | |
6a31c819 | 1020 | @item DBUS_TYPE_SIGNATURE @tab @expansion{} @tab string |
22d8ac3a MA |
1021 | @item DBUS_TYPE_ARRAY @tab @expansion{} @tab list |
1022 | @item DBUS_TYPE_VARIANT @tab @expansion{} @tab list | |
1023 | @item DBUS_TYPE_STRUCT @tab @expansion{} @tab list | |
1024 | @item DBUS_TYPE_DICT_ENTRY @tab @expansion{} @tab list | |
1025 | @end multitable | |
1026 | @end example | |
1027 | ||
d4e67bc5 | 1028 | A float object in case of @code{DBUS_TYPE_UINT32}, |
6f8fc60c MA |
1029 | @code{DBUS_TYPE_INT32}, @code{DBUS_TYPE_UINT64}, |
1030 | @code{DBUS_TYPE_INT64} and @code{DBUS_TYPE_UNIX_FD} is returned, when | |
1031 | the C value exceeds the Emacs number size range. | |
d4e67bc5 | 1032 | |
22d8ac3a MA |
1033 | The resulting list of the last 4 D-Bus compound types contains as |
1034 | elements the elements of the D-Bus container, mapped according to the | |
1035 | same rules. | |
1036 | ||
1037 | The signal @code{PropertyModified}, discussed as example in | |
1038 | @ref{Inspection}, would offer as Lisp data the following object | |
1039 | (@var{BOOL} stands here for either @code{nil} or @code{t}): | |
1040 | ||
1041 | @lisp | |
5bd55c3c | 1042 | (@var{INTEGER} ((@var{STRING} @var{BOOL} @var{BOOL}) (@var{STRING} @var{BOOL} @var{BOOL}) @dots{})) |
22d8ac3a MA |
1043 | @end lisp |
1044 | ||
ace706d1 MA |
1045 | @defun dbus-byte-array-to-string byte-array |
1046 | If a D-Bus method or signal returns an array of bytes, which are known | |
1047 | to represent an UTF8 string, this function converts @var{byte-array} | |
1048 | to the corresponding string. Example: | |
1049 | ||
1050 | @lisp | |
1051 | (dbus-byte-array-to-string '(47 101 116 99 47 104 111 115 116 115)) | |
1052 | ||
1053 | @result{} "/etc/hosts" | |
1054 | @end lisp | |
1055 | @end defun | |
1056 | ||
1057 | @defun dbus-unescape-from-identifier string | |
1058 | Retrieve the original string from the encoded @var{string}. | |
1059 | @var{string} must have been coded with | |
1060 | @code{dbus-escape-as-identifier}. Example: | |
1061 | ||
1062 | @lisp | |
1063 | (dbus-unescape-from-identifier "_30123abc_5fxyz_01_ff") | |
1064 | ||
fa0f81b0 AS |
1065 | @ifinfo |
1066 | @result{} "0123abc_xyz^Aÿ" | |
1067 | @end ifinfo | |
1068 | @ifnotinfo | |
1069 | @result{} "0123abc_xyz^A@"y" | |
1070 | @end ifnotinfo | |
ace706d1 MA |
1071 | @end lisp |
1072 | @end defun | |
1073 | ||
22d8ac3a MA |
1074 | |
1075 | @node Synchronous Methods | |
1076 | @chapter Calling methods in a blocking way. | |
1077 | @cindex method calls, synchronous | |
1078 | @cindex synchronous method calls | |
1079 | ||
1080 | Methods can be called synchronously (@dfn{blocking}) or asynchronously | |
21956b56 | 1081 | (@dfn{non-blocking}). |
22d8ac3a MA |
1082 | |
1083 | At D-Bus level, a method call consist of two messages: one message | |
1084 | which carries the input parameters to the object owning the method to | |
1085 | be called, and a reply message returning the resulting output | |
1086 | parameters from the object. | |
1087 | ||
134ce16c | 1088 | @defun dbus-call-method bus service path interface method &optional :timeout timeout &rest args |
22d8ac3a MA |
1089 | This function calls @var{method} on the D-Bus @var{bus}. @var{bus} is |
1090 | either the symbol @code{:system} or the symbol @code{:session}. | |
1091 | ||
1092 | @var{service} is the D-Bus service name to be used. @var{path} is the | |
1093 | D-Bus object path, @var{service} is registered at. @var{interface} is | |
1094 | an interface offered by @var{service}. It must provide @var{method}. | |
1095 | ||
134ce16c | 1096 | If the parameter @code{:timeout} is given, the following integer |
21956b56 | 1097 | @var{timeout} specifies the maximum number of milliseconds the method |
ecd3d54f | 1098 | call must return. The default value is 25,000. If the method call |
134ce16c MA |
1099 | doesn't return in time, a D-Bus error is raised (@pxref{Errors and |
1100 | Events}). | |
1101 | ||
22d8ac3a MA |
1102 | All other arguments args are passed to @var{method} as arguments. |
1103 | They are converted into D-Bus types as described in @ref{Type | |
1104 | Conversion}. | |
1105 | ||
1106 | The function returns the resulting values of @var{method} as a list of | |
1107 | Lisp objects, according to the type conversion rules described in | |
1108 | @ref{Type Conversion}. Example: | |
1109 | ||
06c0751a | 1110 | @lisp |
22d8ac3a | 1111 | (dbus-call-method |
0ce574ef MA |
1112 | :session "org.gnome.seahorse" "/org/gnome/seahorse/keys/openpgp" |
1113 | "org.gnome.seahorse.Keys" "GetKeyField" | |
22d8ac3a MA |
1114 | "openpgp:657984B8C7A966DD" "simple-name") |
1115 | ||
1116 | @result{} (t ("Philip R. Zimmermann")) | |
06c0751a | 1117 | @end lisp |
22d8ac3a MA |
1118 | |
1119 | If the result of the method call is just one value, the converted Lisp | |
1120 | object is returned instead of a list containing this single Lisp | |
1121 | object. Example: | |
1122 | ||
06c0751a | 1123 | @lisp |
22d8ac3a | 1124 | (dbus-call-method |
0ce574ef MA |
1125 | :system "org.freedesktop.Hal" |
1126 | "/org/freedesktop/Hal/devices/computer" | |
1127 | "org.freedesktop.Hal.Device" "GetPropertyString" | |
22d8ac3a MA |
1128 | "system.kernel.machine") |
1129 | ||
1130 | @result{} "i686" | |
06c0751a | 1131 | @end lisp |
22d8ac3a MA |
1132 | |
1133 | With the @code{dbus-introspect} function it is possible to explore the | |
1134 | interfaces of @samp{org.freedesktop.Hal} service. It offers the | |
1135 | interfaces @samp{org.freedesktop.Hal.Manager} for the object at the | |
1136 | path @samp{/org/freedesktop/Hal/Manager} as well as the interface | |
1137 | @samp{org.freedesktop.Hal.Device} for all objects prefixed with the | |
1138 | path @samp{/org/freedesktop/Hal/devices}. With the methods | |
1139 | @samp{GetAllDevices} and @samp{GetAllProperties}, it is simple to | |
1140 | emulate the @code{lshal} command on GNU/Linux systems: | |
1141 | ||
06c0751a | 1142 | @lisp |
22d8ac3a MA |
1143 | (dolist (device |
1144 | (dbus-call-method | |
0ce574ef | 1145 | :system "org.freedesktop.Hal" |
22d8ac3a | 1146 | "/org/freedesktop/Hal/Manager" |
0ce574ef | 1147 | "org.freedesktop.Hal.Manager" "GetAllDevices")) |
22d8ac3a MA |
1148 | (message "\nudi = %s" device) |
1149 | (dolist (properties | |
1150 | (dbus-call-method | |
0ce574ef MA |
1151 | :system "org.freedesktop.Hal" device |
1152 | "org.freedesktop.Hal.Device" "GetAllProperties")) | |
22d8ac3a MA |
1153 | (message " %s = %S" |
1154 | (car properties) (or (caar (cdr properties)) "")))) | |
1155 | ||
7b13a0f2 | 1156 | @print{} "udi = /org/freedesktop/Hal/devices/computer |
d9e21158 MA |
1157 | info.addons = (\"hald-addon-acpi\") |
1158 | info.bus = \"unknown\" | |
1159 | info.product = \"Computer\" | |
1160 | info.subsystem = \"unknown\" | |
1161 | info.udi = \"/org/freedesktop/Hal/devices/computer\" | |
1162 | linux.sysfs_path_device = \"(none)\" | |
1163 | power_management.acpi.linux.version = \"20051216\" | |
1164 | power_management.can_suspend_to_disk = t | |
1165 | power_management.can_suspend_to_ram = \"\" | |
1166 | power_management.type = \"acpi\" | |
1167 | smbios.bios.release_date = \"11/07/2001\" | |
1168 | system.chassis.manufacturer = \"COMPAL\" | |
1169 | system.chassis.type = \"Notebook\" | |
1170 | system.firmware.release_date = \"03/19/2005\" | |
c9ecb5a7 | 1171 | @dots{}" |
06c0751a | 1172 | @end lisp |
22d8ac3a MA |
1173 | @end defun |
1174 | ||
21956b56 MA |
1175 | @defun dbus-call-method-non-blocking bus service path interface method &optional :timeout timeout &rest args |
1176 | Call @var{method} on the D-Bus @var{bus}, but don't block the event queue. | |
1177 | This is necessary for communicating to registered D-Bus methods, | |
1178 | which are running in the same Emacs process. | |
1179 | ||
1180 | The arguments are the same as in @code{dbus-call-method}. Example: | |
1181 | ||
1182 | @lisp | |
1183 | (dbus-call-method-non-blocking | |
1184 | :system "org.freedesktop.Hal" | |
1185 | "/org/freedesktop/Hal/devices/computer" | |
1186 | "org.freedesktop.Hal.Device" "GetPropertyString" | |
1187 | "system.kernel.machine") | |
1188 | ||
1189 | @result{} "i686" | |
1190 | @end lisp | |
1191 | @end defun | |
1192 | ||
1193 | ||
1194 | @node Asynchronous Methods | |
1195 | @chapter Calling methods non-blocking. | |
1196 | @cindex method calls, asynchronous | |
1197 | @cindex asynchronous method calls | |
1198 | ||
1199 | @defun dbus-call-method-asynchronously bus service path interface method handler &optional :timeout timeout &rest args | |
1200 | This function calls @var{method} on the D-Bus @var{bus} | |
1201 | asynchronously. @var{bus} is either the symbol @code{:system} or the | |
1202 | symbol @code{:session}. | |
1203 | ||
1204 | @var{service} is the D-Bus service name to be used. @var{path} is the | |
1205 | D-Bus object path, @var{service} is registered at. @var{interface} is | |
1206 | an interface offered by @var{service}. It must provide @var{method}. | |
1207 | ||
1208 | @var{handler} is a Lisp function, which is called when the | |
4f22e84d MA |
1209 | corresponding return message has arrived. If @var{handler} is |
1210 | @code{nil}, no return message will be expected. | |
21956b56 MA |
1211 | |
1212 | If the parameter @code{:timeout} is given, the following integer | |
1213 | @var{timeout} specifies the maximum number of milliseconds a reply | |
ecd3d54f | 1214 | message must arrive. The default value is 25,000. If there is no |
21956b56 MA |
1215 | reply message in time, a D-Bus error is raised (@pxref{Errors and |
1216 | Events}). | |
1217 | ||
1218 | All other arguments args are passed to @var{method} as arguments. | |
1219 | They are converted into D-Bus types as described in @ref{Type | |
1220 | Conversion}. | |
1221 | ||
4f22e84d | 1222 | Unless @var{handler} is @code{nil}, the function returns a key into |
0ecd3c90 | 1223 | the hash table @code{dbus-registered-objects-table}. The |
4f22e84d MA |
1224 | corresponding entry in the hash table is removed, when the return |
1225 | message has been arrived, and @var{handler} is called. Example: | |
21956b56 MA |
1226 | |
1227 | @lisp | |
1228 | (dbus-call-method-asynchronously | |
1229 | :system "org.freedesktop.Hal" | |
1230 | "/org/freedesktop/Hal/devices/computer" | |
1231 | "org.freedesktop.Hal.Device" "GetPropertyString" 'message | |
1232 | "system.kernel.machine") | |
1233 | ||
1234 | @result{} (:system 2) | |
1235 | ||
1236 | @print{} i686 | |
1237 | @end lisp | |
1238 | @end defun | |
1239 | ||
22d8ac3a | 1240 | |
addb7f2e MA |
1241 | @node Receiving Method Calls |
1242 | @chapter Offering own methods. | |
1243 | @cindex method calls, returning | |
1244 | @cindex returning method calls | |
1245 | ||
8c904d82 MA |
1246 | In order to register methods on the D-Bus, Emacs has to request a well |
1247 | known name on the D-Bus under which it will be available for other | |
1248 | clients. Names on the D-Bus can be registered and unregistered using | |
1249 | the following functions: | |
1250 | ||
1251 | @defun dbus-register-service bus service &rest flags | |
1252 | Register the known name @var{service} on D-Bus @var{bus}. | |
1253 | ||
1254 | @var{bus} is either the symbol @code{:system} or the symbol | |
1255 | @code{:session}. | |
1256 | ||
1257 | @var{service} is the service name to be registered on the D-Bus. It | |
1258 | must be a known name. | |
1259 | ||
1260 | @var{flags} is a subset of the following keywords: | |
1261 | ||
1262 | @itemize | |
1263 | @item @code{:allow-replacement}: Allow another service to become the primary | |
1264 | owner if requested. | |
1265 | ||
1266 | @item @code{:replace-existing}: Request to replace the current primary owner. | |
1267 | ||
1268 | @item @code{:do-not-queue}: If we can not become the primary owner do not | |
1269 | place us in the queue. | |
1270 | @end itemize | |
1271 | ||
1272 | One of the following keywords is returned: | |
1273 | ||
1274 | @itemize | |
1275 | ||
1276 | @item @code{:primary-owner}: We have become the primary owner of the name | |
1277 | @var{service}. | |
1278 | ||
1279 | @item @code{:in-queue}: We could not become the primary owner and | |
1280 | have been placed in the queue. | |
1281 | ||
1282 | @item @code{:exists}: We already are in the queue. | |
1283 | ||
1284 | @item @code{:already-owner}: We already are the primary | |
1285 | owner. | |
1286 | @end itemize | |
1287 | @end defun | |
1288 | ||
1289 | @defun dbus-unregister-service bus service | |
1290 | Unregister all objects from D-Bus @var{bus}, registered by Emacs for | |
1291 | @var{service}. | |
1292 | ||
1293 | @var{bus} is either the symbol @code{:system} or the symbol | |
1294 | @code{:session}. | |
1295 | ||
1296 | @var{service} is the D-Bus service name of the D-Bus. It must be a | |
1297 | known name. Emacs releases its association to @var{service} from | |
1298 | D-Bus. | |
1299 | ||
1300 | One of the following keywords is returned: | |
1301 | ||
1302 | @itemize | |
1303 | @item @code{:released}: We successfully released the name @var{service}. | |
1304 | @item @code{:non-existent}: The name @var{service} does not exist on the bus. | |
1305 | @item @code{:not-owner}: We are not an owner of the name @var{service}. | |
1306 | @end itemize | |
1307 | @end defun | |
1308 | ||
1309 | When a name has been chosen, Emacs can offer own methods, which can be | |
1310 | called by other applications. These methods could be an | |
1311 | implementation of an interface of a well known service, like | |
1312 | @samp{org.freedesktop.TextEditor}. | |
addb7f2e MA |
1313 | |
1314 | It could be also an implementation of an own interface. In this case, | |
cd71b9ae MA |
1315 | the service name must be @samp{org.gnu.Emacs}. The object path shall |
1316 | begin with @samp{/org/gnu/Emacs/@strong{Application}/}, and the | |
addb7f2e | 1317 | interface name shall be @code{org.gnu.Emacs.@strong{Application}}. |
cd71b9ae | 1318 | @samp{@strong{Application}} is the name of the application which |
addb7f2e MA |
1319 | provides the interface. |
1320 | ||
ace706d1 MA |
1321 | @deffn Constant dbus-service-emacs |
1322 | The well known service name of Emacs. | |
1323 | @end deffn | |
1324 | ||
1325 | @deffn Constant dbus-path-emacs | |
1326 | The object path head "/org/gnu/Emacs" used by Emacs. All object | |
1327 | paths, used by offered methods or signals, shall start with this | |
1328 | string. | |
1329 | @end deffn | |
1330 | ||
0fadf00e | 1331 | @defun dbus-register-method bus service path interface method handler dont-register-service |
addb7f2e MA |
1332 | With this function, an application registers @var{method} on the D-Bus |
1333 | @var{bus}. | |
1334 | ||
1335 | @var{bus} is either the symbol @code{:system} or the symbol | |
1336 | @code{:session}. | |
1337 | ||
1338 | @var{service} is the D-Bus service name of the D-Bus object | |
0fadf00e MA |
1339 | @var{method} is registered for. It must be a known name (See |
1340 | discussion of @var{dont-register-service} below). | |
addb7f2e | 1341 | |
0fadf00e MA |
1342 | @var{path} is the D-Bus object path @var{service} is registered (See |
1343 | discussion of @var{dont-register-service} below). | |
addb7f2e MA |
1344 | |
1345 | @var{interface} is the interface offered by @var{service}. It must | |
1346 | provide @var{method}. | |
1347 | ||
ac134f2f RS |
1348 | @var{handler} is a Lisp function to be called when a @var{method} call |
1349 | is received. It must accept as arguments the input arguments of | |
1350 | @var{method}. @var{handler} should return a list, whose elements are | |
1351 | to be used as arguments for the reply message of @var{method}. This | |
1352 | list can be composed like the input parameters in @ref{Type | |
1353 | Conversion}. | |
1354 | ||
1355 | If @var{handler} wants to return just one Lisp object and it is not a | |
1356 | cons cell, @var{handler} can return this object directly, instead of | |
1357 | returning a list containing the object. | |
addb7f2e | 1358 | |
42fb7e61 MA |
1359 | In case @var{handler} shall return a reply message with an empty |
1360 | argument list, @var{handler} must return the symbol @code{:ignore}. | |
1361 | ||
0fadf00e MA |
1362 | When @var{dont-register-service} is non-@code{nil}, the known name |
1363 | @var{service} is not registered. This means that other D-Bus clients | |
1364 | have no way of noticing the newly registered method. When interfaces | |
1365 | are constructed incrementally by adding single methods or properties | |
8c904d82 | 1366 | at a time, @var{dont-register-service} can be used to prevent other |
0fadf00e MA |
1367 | clients from discovering the still incomplete interface. |
1368 | ||
4a7c4c40 | 1369 | The default D-Bus timeout when waiting for a message reply is 25 |
134ce16c MA |
1370 | seconds. This value could be even smaller, depending on the calling |
1371 | client. Therefore, @var{handler} shall not last longer than | |
4a7c4c40 MA |
1372 | absolutely necessary. |
1373 | ||
9b7993b4 | 1374 | @code{dbus-register-method} returns a Lisp object, which can be used |
addb7f2e MA |
1375 | as argument in @code{dbus-unregister-object} for removing the |
1376 | registration for @var{method}. Example: | |
1377 | ||
06c0751a | 1378 | @lisp |
addb7f2e MA |
1379 | (defun my-dbus-method-handler (filename) |
1380 | (let (result) | |
1381 | (if (find-file filename) | |
1382 | (setq result '(:boolean t)) | |
1383 | (setq result '(:boolean nil))) | |
1384 | result)) | |
1385 | ||
1386 | @result{} my-dbus-method-handler | |
1387 | ||
1388 | (dbus-register-method | |
1389 | :session "org.freedesktop.TextEditor" "/org/freedesktop/TextEditor" | |
1390 | "org.freedesktop.TextEditor" "OpenFile" | |
1391 | 'my-dbus-method-handler) | |
1392 | ||
eb932e8a | 1393 | @result{} ((:session "org.freedesktop.TextEditor" "OpenFile") |
addb7f2e | 1394 | ("org.freedesktop.TextEditor" "/org/freedesktop/TextEditor" |
eb932e8a | 1395 | my-dbus-method-handler)) |
06c0751a | 1396 | @end lisp |
addb7f2e | 1397 | |
cd71b9ae | 1398 | If you invoke the method @samp{org.freedesktop.TextEditor.OpenFile} |
addb7f2e MA |
1399 | from another D-Bus application with a filename as parameter, the file |
1400 | is opened in Emacs, and the method returns either @var{true} or | |
0ecd3c90 | 1401 | @var{false}, indicating the success of the method. As test tool one |
addb7f2e MA |
1402 | could use the command line tool @code{dbus-send} in a shell: |
1403 | ||
1404 | @example | |
1405 | # dbus-send --session --print-reply \ | |
1406 | --dest="org.freedesktop.TextEditor" \ | |
1407 | "/org/freedesktop/TextEditor" \ | |
1408 | "org.freedesktop.TextEditor.OpenFile" string:"/etc/hosts" | |
1409 | ||
1410 | @print{} method return sender=:1.22 -> dest=:1.23 reply_serial=2 | |
eb932e8a MA |
1411 | boolean true |
1412 | @end example | |
1413 | ||
1414 | You can indicate an error by raising the Emacs signal | |
1415 | @code{dbus-error}. The handler above could be changed like this: | |
1416 | ||
1417 | @lisp | |
1418 | (defun my-dbus-method-handler (&rest args) | |
1419 | (unless (and (= (length args) 1) (stringp (car args))) | |
1420 | (signal 'dbus-error (list (format "Wrong argument list: %S" args)))) | |
1421 | (condition-case err | |
1422 | (find-file (car args)) | |
1423 | (error (signal 'dbus-error (cdr err)))) | |
1424 | t) | |
1425 | ||
1426 | @result{} my-dbus-method-handler | |
1427 | @end lisp | |
1428 | ||
1429 | The test runs then | |
1430 | ||
1431 | @example | |
1432 | # dbus-send --session --print-reply \ | |
1433 | --dest="org.freedesktop.TextEditor" \ | |
1434 | "/org/freedesktop/TextEditor" \ | |
1435 | "org.freedesktop.TextEditor.OpenFile" \ | |
1436 | string:"/etc/hosts" string:"/etc/passwd" | |
1437 | ||
1438 | @print{} Error org.freedesktop.DBus.Error.Failed: | |
1439 | Wrong argument list: ("/etc/hosts" "/etc/passwd") | |
addb7f2e MA |
1440 | @end example |
1441 | @end defun | |
1442 | ||
0fadf00e | 1443 | @defun dbus-register-property bus service path interface property access value &optional emits-signal dont-register-service |
0ecd3c90 MA |
1444 | With this function, an application declares a @var{property} on the D-Bus |
1445 | @var{bus}. | |
1446 | ||
1447 | @var{bus} is either the symbol @code{:system} or the symbol | |
1448 | @code{:session}. | |
1449 | ||
1450 | @var{service} is the D-Bus service name of the D-Bus. It must be a | |
1451 | known name. | |
1452 | ||
0fadf00e MA |
1453 | @var{path} is the D-Bus object path @var{service} is registered (See |
1454 | discussion of @var{dont-register-service} below). | |
0ecd3c90 MA |
1455 | |
1456 | @var{interface} is the name of the interface used at @var{path}, | |
1457 | @var{property} is the name of the property of @var{interface}. | |
1458 | ||
1459 | @var{access} indicates, whether the property can be changed by other | |
1460 | services via D-Bus. It must be either the symbol @code{:read} or | |
1461 | @code{:readwrite}. @var{value} is the initial value of the property, | |
1462 | it can be of any valid type (see @code{dbus-call-method} for details). | |
1463 | ||
1464 | If @var{property} already exists on @var{path}, it will be | |
1465 | overwritten. For properties with access type @code{:read} this is the | |
1466 | only way to change their values. Properties with access type | |
1467 | @code{:readwrite} can be changed by @code{dbus-set-property}. | |
1468 | ||
1469 | The interface @samp{org.freedesktop.DBus.Properties} is added to | |
1470 | @var{path}, including a default handler for the @samp{Get}, | |
820ae8fe | 1471 | @samp{GetAll} and @samp{Set} methods of this interface. When |
5bd55c3c MA |
1472 | @var{emits-signal} is non-@code{nil}, the signal |
1473 | @samp{PropertiesChanged} is sent when the property is changed by | |
1474 | @code{dbus-set-property}. | |
820ae8fe | 1475 | |
0fadf00e MA |
1476 | When @var{dont-register-service} is non-@code{nil}, the known name |
1477 | @var{service} is not registered. This means that other D-Bus clients | |
1478 | have no way of noticing the newly registered method. When interfaces | |
1479 | are constructed incrementally by adding single methods or properties | |
8c904d82 | 1480 | at a time, @var{dont-register-service} can be used to prevent other |
0fadf00e MA |
1481 | clients from discovering the still incomplete interface. |
1482 | ||
820ae8fe | 1483 | @noindent Example: |
0ecd3c90 MA |
1484 | |
1485 | @lisp | |
1486 | (dbus-register-property | |
1487 | :session "org.freedesktop.TextEditor" "/org/freedesktop/TextEditor" | |
1488 | "org.freedesktop.TextEditor" "name" :read "GNU Emacs") | |
1489 | ||
1490 | @result{} ((:session "org.freedesktop.TextEditor" "name") | |
1491 | ("org.freedesktop.TextEditor" "/org/freedesktop/TextEditor")) | |
1492 | ||
1493 | (dbus-register-property | |
1494 | :session "org.freedesktop.TextEditor" "/org/freedesktop/TextEditor" | |
820ae8fe | 1495 | "org.freedesktop.TextEditor" "version" :readwrite emacs-version t) |
0ecd3c90 MA |
1496 | |
1497 | @result{} ((:session "org.freedesktop.TextEditor" "version") | |
1498 | ("org.freedesktop.TextEditor" "/org/freedesktop/TextEditor")) | |
1499 | @end lisp | |
1500 | ||
1501 | Other D-Bus applications can read the property via the default methods | |
1502 | @samp{org.freedesktop.DBus.Properties.Get} and | |
1503 | @samp{org.freedesktop.DBus.Properties.GetAll}. Testing is also | |
1504 | possible via the command line tool @code{dbus-send} in a shell: | |
1505 | ||
1506 | @example | |
1507 | # dbus-send --session --print-reply \ | |
1508 | --dest="org.freedesktop.TextEditor" \ | |
1509 | "/org/freedesktop/TextEditor" \ | |
1510 | "org.freedesktop.DBus.Properties.GetAll" \ | |
1511 | string:"org.freedesktop.TextEditor" | |
1512 | ||
1513 | @print{} method return sender=:1.22 -> dest=:1.23 reply_serial=3 | |
1514 | array [ | |
1515 | dict entry( | |
1516 | string "name" | |
1517 | variant string "GNU Emacs" | |
1518 | ) | |
1519 | dict entry( | |
1520 | string "version" | |
1521 | variant string "23.1.50.5" | |
1522 | ) | |
1523 | ] | |
1524 | @end example | |
1525 | ||
1526 | It is also possible, to apply the @code{dbus-get-property}, | |
1527 | @code{dbus-get-all-properties} and @code{dbus-set-property} functions | |
1528 | (@pxref{Properties and Annotations}). | |
1529 | ||
1530 | @lisp | |
1531 | (dbus-set-property | |
1532 | :session "org.freedesktop.TextEditor" "/org/freedesktop/TextEditor" | |
1533 | "org.freedesktop.TextEditor" "version" "23.1.50") | |
1534 | ||
1535 | @result{} "23.1.50" | |
1536 | ||
1537 | (dbus-get-property | |
1538 | :session "org.freedesktop.TextEditor" "/org/freedesktop/TextEditor" | |
1539 | "org.freedesktop.TextEditor" "version") | |
1540 | ||
1541 | @result{} "23.1.50" | |
1542 | @end lisp | |
1543 | @end defun | |
1544 | ||
1545 | @defun dbus-unregister-object object | |
1546 | Unregister @var{object} from the D-Bus. @var{object} must be the | |
1547 | result of a preceding @code{dbus-register-method}, | |
1548 | @code{dbus-register-property} or @code{dbus-register-signal} call | |
1549 | (@pxref{Signals}). It returns @code{t} if @var{object} has been | |
1550 | unregistered, @code{nil} otherwise. | |
1551 | ||
1552 | When @var{object} identifies the last method or property, which is | |
1553 | registered for the respective service, Emacs releases its association | |
1554 | to the service from D-Bus. | |
1555 | @end defun | |
977640ed | 1556 | |
addb7f2e | 1557 | |
22d8ac3a MA |
1558 | @node Signals |
1559 | @chapter Sending and receiving signals. | |
1560 | @cindex signals | |
1561 | ||
1562 | Signals are broadcast messages. They carry input parameters, which | |
1563 | are received by all objects which have registered for such a signal. | |
1564 | ||
0ce574ef | 1565 | @defun dbus-send-signal bus service path interface signal &rest args |
22d8ac3a MA |
1566 | This function is similar to @code{dbus-call-method}. The difference |
1567 | is, that there are no returning output parameters. | |
1568 | ||
1569 | The function emits @var{signal} on the D-Bus @var{bus}. @var{bus} is | |
1570 | either the symbol @code{:system} or the symbol @code{:session}. It | |
1571 | doesn't matter whether another object has registered for @var{signal}. | |
1572 | ||
1573 | @var{service} is the D-Bus service name of the object the signal is | |
1574 | emitted from. @var{path} is the corresponding D-Bus object path, | |
1575 | @var{service} is registered at. @var{interface} is an interface | |
1576 | offered by @var{service}. It must provide @var{signal}. | |
1577 | ||
1578 | All other arguments args are passed to @var{signal} as arguments. | |
1579 | They are converted into D-Bus types as described in @ref{Type | |
1580 | Conversion}. Example: | |
1581 | ||
06c0751a | 1582 | @lisp |
22d8ac3a | 1583 | (dbus-send-signal |
ace706d1 MA |
1584 | :session dbus-service-emacs dbus-path-emacs |
1585 | (concat dbus-service-emacs ".FileManager") "FileModified" | |
1586 | "/home/albinus/.emacs") | |
06c0751a | 1587 | @end lisp |
22d8ac3a MA |
1588 | @end defun |
1589 | ||
9b7993b4 | 1590 | @defun dbus-register-signal bus service path interface signal handler &rest args |
22d8ac3a MA |
1591 | With this function, an application registers for @var{signal} on the |
1592 | D-Bus @var{bus}. | |
1593 | ||
1594 | @var{bus} is either the symbol @code{:system} or the symbol | |
1595 | @code{:session}. | |
1596 | ||
a4397af9 MA |
1597 | @var{service} is the D-Bus service name used by the sending D-Bus |
1598 | object. It can be either a known name or the unique name of the D-Bus | |
1599 | object sending the signal. In case of a unique name, signals won't be | |
1600 | received any longer once the object owning this unique name has | |
1601 | disappeared, and a new queued object has replaced it. | |
1602 | ||
1603 | When @var{service} is @code{nil}, related signals from all D-Bus | |
1604 | objects shall be accepted. | |
1605 | ||
1606 | @var{path} is the corresponding D-Bus object path, @var{service} is | |
1607 | registered at. It can also be @code{nil} if the path name of incoming | |
1608 | signals shall not be checked. | |
1609 | ||
1610 | @var{interface} is an interface offered by @var{service}. It must | |
1611 | provide @var{signal}. | |
22d8ac3a MA |
1612 | |
1613 | @var{handler} is a Lisp function to be called when the @var{signal} is | |
1614 | received. It must accept as arguments the output parameters | |
9b7993b4 MA |
1615 | @var{signal} is sending. |
1616 | ||
1617 | All other arguments @var{args}, if specified, must be strings. They | |
1618 | stand for the respective arguments of @var{signal} in their order, and | |
1619 | are used for filtering as well. A @code{nil} argument might be used | |
1620 | to preserve the order. | |
1621 | ||
1622 | @code{dbus-register-signal} returns a Lisp object, which can be used | |
1623 | as argument in @code{dbus-unregister-object} for removing the | |
1624 | registration for @var{signal}. Example: | |
22d8ac3a | 1625 | |
06c0751a | 1626 | @lisp |
22d8ac3a MA |
1627 | (defun my-dbus-signal-handler (device) |
1628 | (message "Device %s added" device)) | |
1629 | ||
0ce574ef MA |
1630 | @result{} my-dbus-signal-handler |
1631 | ||
22d8ac3a | 1632 | (dbus-register-signal |
0ce574ef MA |
1633 | :system "org.freedesktop.Hal" "/org/freedesktop/Hal/Manager" |
1634 | "org.freedesktop.Hal.Manager" "DeviceAdded" | |
22d8ac3a MA |
1635 | 'my-dbus-signal-handler) |
1636 | ||
cd71c3ef MA |
1637 | @result{} ((:system "org.freedesktop.Hal.Manager" "DeviceAdded") |
1638 | ("org.freedesktop.Hal" "/org/freedesktop/Hal/Manager" | |
1639 | my-signal-handler)) | |
06c0751a | 1640 | @end lisp |
22d8ac3a | 1641 | |
cd71b9ae MA |
1642 | As we know from the introspection data of interface |
1643 | @samp{org.freedesktop.Hal.Manager}, the signal @samp{DeviceAdded} | |
22d8ac3a MA |
1644 | provides one single parameter, which is mapped into a Lisp string. |
1645 | The callback function @code{my-dbus-signal-handler} must define one | |
1646 | single string argument therefore. Plugging an USB device to your | |
cd71b9ae | 1647 | machine, when registered for signal @samp{DeviceAdded}, will show you |
22d8ac3a | 1648 | which objects the GNU/Linux @code{hal} daemon adds. |
22d8ac3a MA |
1649 | @end defun |
1650 | ||
22d8ac3a | 1651 | |
7457f7b6 MA |
1652 | @node Alternative Buses |
1653 | @chapter Alternative buses. | |
1654 | @cindex bus names | |
1655 | @cindex UNIX domain socket | |
1656 | ||
1657 | Until now, we have spoken about the system and the session buses, | |
1658 | which are the default buses to be connected to. However, it is | |
1659 | possible to connect to any bus, from which the address is known. This | |
1660 | is a UNIX domain socket. Everywhere, where a @var{bus} is mentioned | |
1661 | as argument of a function (the symbol @code{:system} or the symbol | |
1662 | @code{:session}), this address can be used instead. The connection to | |
1663 | this bus must be initialized first. | |
1664 | ||
1665 | @defun dbus-init-bus bus | |
1666 | Establish the connection to D-Bus @var{bus}. | |
1667 | ||
1668 | @var{bus} can be either the symbol @code{:system} or the symbol | |
1669 | @code{:session}, or it can be a string denoting the address of the | |
1670 | corresponding bus. For the system and session busses, this function | |
1671 | is called when loading @file{dbus.el}, there is no need to call it | |
1672 | again. | |
1673 | ||
1674 | Example: You open another session bus in a terminal window on your host: | |
1675 | ||
1676 | @example | |
1677 | # eval `dbus-launch --auto-syntax` | |
1678 | # echo $DBUS_SESSION_BUS_ADDRESS | |
1679 | ||
1680 | @print{} unix:abstract=/tmp/dbus-JoFtAVG92w,guid=2f320a1ebe50b7ef58e | |
1681 | @end example | |
1682 | ||
1683 | In Emacs, you can access to this bus via its address: | |
1684 | ||
1685 | @lisp | |
1686 | (setq my-bus | |
1687 | "unix:abstract=/tmp/dbus-JoFtAVG92w,guid=2f320a1ebe50b7ef58e") | |
1688 | ||
1689 | @result{} "unix:abstract=/tmp/dbus-JoFtAVG92w,guid=2f320a1ebe50b7ef58e" | |
1690 | ||
1691 | (dbus-init-bus my-bus) | |
1692 | ||
1693 | @result{} nil | |
1694 | ||
1695 | (dbus-get-unique-name my-bus) | |
1696 | ||
1697 | @result{} ":1.0" | |
1698 | @end lisp | |
1699 | @end defun | |
1700 | ||
1701 | ||
22d8ac3a MA |
1702 | @node Errors and Events |
1703 | @chapter Errors and events. | |
5bd55c3c | 1704 | @cindex debugging |
22d8ac3a MA |
1705 | @cindex errors |
1706 | @cindex events | |
1707 | ||
5bd55c3c MA |
1708 | The internal actions can be traced by running in a debug mode. |
1709 | ||
1710 | @defvar dbus-debug | |
1711 | If this variable is non-@code{nil}, D-Bus specific debug messages are raised. | |
1712 | @end defvar | |
1713 | ||
21956b56 MA |
1714 | Input parameters of @code{dbus-call-method}, |
1715 | @code{dbus-call-method-non-blocking}, | |
1716 | @code{dbus-call-method-asynchronously}, and | |
6a31c819 MA |
1717 | @code{dbus-register-signal} are checked for correct D-Bus types. If |
1718 | there is a type mismatch, the Lisp error @code{wrong-type-argument} | |
1719 | @code{D-Bus ARG} is raised. | |
1720 | ||
22d8ac3a | 1721 | All errors raised by D-Bus are signaled with the error symbol |
d2e4a6c9 MA |
1722 | @code{dbus-error}. If possible, error messages from D-Bus are |
1723 | appended to the @code{dbus-error}. | |
1724 | ||
1725 | @defspec dbus-ignore-errors forms@dots{} | |
1726 | This executes @var{forms} exactly like a @code{progn}, except that | |
1727 | @code{dbus-error} errors are ignored during the @var{forms}. These | |
5bd55c3c | 1728 | errors can be made visible when @code{dbus-debug} is set to @code{t}. |
d2e4a6c9 | 1729 | @end defspec |
22d8ac3a | 1730 | |
5794c2a5 MA |
1731 | Incoming D-Bus messages are handled as Emacs events, see @pxref{Misc |
1732 | Events, , , elisp}. They are retrieved only, when Emacs runs in | |
1733 | interactive mode. The generated event has this form: | |
22d8ac3a | 1734 | |
06c0751a | 1735 | @lisp |
21956b56 MA |
1736 | (dbus-event @var{bus} @var{type} @var{serial} @var{service} @var{path} @var{interface} @var{member} @var{handler} |
1737 | &rest @var{args}) | |
06c0751a | 1738 | @end lisp |
22d8ac3a | 1739 | |
21956b56 | 1740 | @var{bus} identifies the D-Bus the message is coming from. It is |
a4397af9 | 1741 | either the symbol @code{:system} or the symbol @code{:session}. |
22d8ac3a | 1742 | |
21956b56 MA |
1743 | @var{type} is the D-Bus message type which has caused the event. It |
1744 | can be @code{dbus-message-type-invalid}, | |
1745 | @code{dbus-message-type-method-call}, | |
1746 | @code{dbus-message-type-method-return}, | |
1747 | @code{dbus-message-type-error}, or @code{dbus-message-type-signal}. | |
1748 | @var{serial} is the serial number of the received D-Bus message. | |
addb7f2e | 1749 | |
22d8ac3a | 1750 | @var{service} and @var{path} are the unique name and the object path |
addb7f2e MA |
1751 | of the D-Bus object emitting the message. @var{interface} and |
1752 | @var{member} denote the message which has been sent. | |
22d8ac3a | 1753 | |
0ce574ef | 1754 | @var{handler} is the callback function which has been registered for |
addb7f2e | 1755 | this message (see @pxref{Signals}). When a @code{dbus-event} event |
0ce574ef MA |
1756 | arrives, @var{handler} is called with @var{args} as arguments. |
1757 | ||
22d8ac3a MA |
1758 | In order to inspect the @code{dbus-event} data, you could extend the |
1759 | definition of the callback function in @ref{Signals}: | |
1760 | ||
06c0751a | 1761 | @lisp |
22d8ac3a MA |
1762 | (defun my-dbus-signal-handler (&rest args) |
1763 | (message "my-dbus-signal-handler: %S" last-input-event)) | |
06c0751a | 1764 | @end lisp |
22d8ac3a MA |
1765 | |
1766 | There exist convenience functions which could be called inside a | |
1767 | callback function in order to retrieve the information from the event. | |
1768 | ||
1769 | @defun dbus-event-bus-name event | |
22d8ac3a MA |
1770 | Returns the bus name @var{event} is coming from. |
1771 | The result is either the symbol @code{:system} or the symbol @code{:session}. | |
1772 | @end defun | |
1773 | ||
21956b56 MA |
1774 | @defun dbus-event-message-type event |
1775 | Returns the message type of the corresponding D-Bus message. The | |
5bd55c3c | 1776 | result is a natural number. |
21956b56 MA |
1777 | @end defun |
1778 | ||
addb7f2e MA |
1779 | @defun dbus-event-serial-number event |
1780 | Returns the serial number of the corresponding D-Bus message. | |
5bd55c3c | 1781 | The result is a natural number. |
addb7f2e MA |
1782 | @end defun |
1783 | ||
22d8ac3a | 1784 | @defun dbus-event-service-name event |
22d8ac3a MA |
1785 | Returns the unique name of the D-Bus object @var{event} is coming from. |
1786 | @end defun | |
1787 | ||
1788 | @defun dbus-event-path-name event | |
22d8ac3a MA |
1789 | Returns the object path of the D-Bus object @var{event} is coming from. |
1790 | @end defun | |
1791 | ||
1792 | @defun dbus-event-interface-name event | |
74fc5047 | 1793 | Returns the interface name of the D-Bus object @var{event} is coming from. |
22d8ac3a MA |
1794 | @end defun |
1795 | ||
1796 | @defun dbus-event-member-name event | |
74fc5047 | 1797 | Returns the member name of the D-Bus object @var{event} is coming |
22d8ac3a MA |
1798 | from. It is either a signal name or a method name. |
1799 | @end defun | |
1800 | ||
c9ecb5a7 MA |
1801 | D-Bus errors are not propagated during event handling, because it is |
1802 | usually not desired. D-Bus errors in events can be made visible by | |
e7433508 MA |
1803 | setting the variable @code{dbus-debug} to @code{t}. They can also be |
1804 | handled by a hook function. | |
1805 | ||
1806 | @defvar dbus-event-error-hooks | |
1807 | This hook variable keeps a list of functions, which are called when a | |
1808 | D-Bus error happens in the event handler. Every function must accept | |
74fc5047 MA |
1809 | two arguments, the event and the error variable catched in |
1810 | @code{condition-case} by @code{dbus-error}. | |
1811 | ||
1812 | Such functions can be used the adapt the error signal to be raised. | |
1813 | Example: | |
e7433508 MA |
1814 | |
1815 | @lisp | |
74fc5047 MA |
1816 | (defun my-dbus-event-error-handler (event error) |
1817 | (when (string-equal (concat dbus-service-emacs ".FileManager") | |
1818 | (dbus-event-interface-name event)) | |
1819 | (message "my-dbus-event-error-handler: %S %S" event error) | |
1820 | (signal 'file-error (cdr error)))) | |
e7433508 MA |
1821 | |
1822 | (add-hook 'dbus-event-error-hooks 'my-dbus-event-error-handler) | |
1823 | @end lisp | |
1824 | @end defvar | |
c9ecb5a7 | 1825 | |
74fc5047 MA |
1826 | Hook functions shall take into account, that there might be other |
1827 | D-Bus applications running. Therefore, they shall check carefully, | |
1828 | whether a given D-Bus error is related to them. | |
1829 | ||
22d8ac3a | 1830 | |
5bd55c3c MA |
1831 | @node Index |
1832 | @unnumbered Index | |
1833 | ||
1834 | @printindex cp | |
1835 | ||
1836 | ||
22d8ac3a MA |
1837 | @node GNU Free Documentation License |
1838 | @appendix GNU Free Documentation License | |
1839 | @include doclicense.texi | |
1840 | ||
22d8ac3a | 1841 | @bye |