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1 | ;;; HTTP request objects |
2 | ||
3 | ;; Copyright (C) 2010 Free Software Foundation, Inc. | |
4 | ||
5 | ;; This library is free software; you can redistribute it and/or | |
6 | ;; modify it under the terms of the GNU Lesser General Public | |
7 | ;; License as published by the Free Software Foundation; either | |
8 | ;; version 3 of the License, or (at your option) any later version. | |
9 | ;; | |
10 | ;; This library is distributed in the hope that it will be useful, | |
11 | ;; but WITHOUT ANY WARRANTY; without even the implied warranty of | |
12 | ;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
13 | ;; Lesser General Public License for more details. | |
14 | ;; | |
15 | ;; You should have received a copy of the GNU Lesser General Public | |
16 | ;; License along with this library; if not, write to the Free Software | |
17 | ;; Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA | |
18 | ;; 02110-1301 USA | |
19 | ||
20 | ;;; Code: | |
21 | ||
22 | (define-module (web request) | |
23 | #:use-module (rnrs bytevectors) | |
24 | #:use-module (rnrs io ports) | |
25 | #:use-module (ice-9 rdelim) | |
26 | #:use-module (srfi srfi-9) | |
27 | #:use-module (web uri) | |
28 | #:use-module (web http) | |
29 | #:export (request? | |
30 | request-method | |
31 | request-uri | |
32 | request-version | |
33 | request-headers | |
34 | request-port | |
35 | ||
36 | read-request | |
37 | build-request | |
38 | write-request | |
39 | ||
40 | read-request-body/latin-1 | |
41 | write-request-body/latin-1 | |
42 | ||
43 | read-request-body/bytevector | |
44 | write-request-body/bytevector | |
45 | ||
46 | ;; General headers | |
47 | ;; | |
48 | request-cache-control | |
49 | request-connection | |
50 | request-date | |
51 | request-pragma | |
52 | request-trailer | |
53 | request-transfer-encoding | |
54 | request-upgrade | |
55 | request-via | |
56 | request-warning | |
57 | ||
58 | ;; Entity headers | |
59 | ;; | |
60 | request-allow | |
61 | request-content-encoding | |
62 | request-content-language | |
63 | request-content-length | |
64 | request-content-location | |
65 | request-content-md5 | |
66 | request-content-range | |
67 | request-content-type | |
68 | request-expires | |
69 | request-last-modified | |
70 | ||
71 | ;; Request headers | |
72 | ;; | |
73 | request-accept | |
74 | request-accept-charset | |
75 | request-accept-encoding | |
76 | request-accept-language | |
77 | request-authorization | |
78 | request-expect | |
79 | request-from | |
80 | request-host | |
81 | request-if-match | |
82 | request-if-modified-since | |
83 | request-if-none-match | |
84 | request-if-range | |
85 | request-if-unmodified-since | |
86 | request-max-forwards | |
87 | request-proxy-authorization | |
88 | request-range | |
89 | request-referer | |
90 | request-te | |
91 | request-user-agent | |
92 | ||
93 | ;; Misc | |
94 | request-absolute-uri)) | |
95 | ||
96 | ||
97 | ;;; {Character Encodings, Strings, and Bytevectors} | |
98 | ;;; | |
99 | ;;; Requests are read from over the wire, and as such have to be treated | |
100 | ;;; very carefully. | |
101 | ;;; | |
102 | ;;; The header portion of the message is defined to be in a subset of | |
103 | ;;; ASCII, and may be processed either byte-wise (using bytevectors and | |
104 | ;;; binary I/O) or as characters in a single-byte ASCII-compatible | |
105 | ;;; encoding. | |
106 | ;;; | |
107 | ;;; We choose the latter, processing as strings in the latin-1 | |
108 | ;;; encoding. This allows us to use all the read-delimited machinery, | |
109 | ;;; character sets, and regular expressions, shared substrings, etc. | |
110 | ;;; | |
111 | ;;; The characters in the header values may themselves encode other | |
112 | ;;; bytes or characters -- basically each header has its own parser. We | |
113 | ;;; leave that as a header-specific topic. | |
114 | ;;; | |
115 | ;;; The body is present if the content-length header is present. Its | |
116 | ;;; format and, if textual, encoding is determined by the headers, but | |
117 | ;;; its length is encoded in bytes. So we just slurp that number of | |
118 | ;;; characters in latin-1, knowing that the number of characters | |
119 | ;;; corresponds to the number of bytes, and then convert to a | |
120 | ;;; bytevector, perhaps for later decoding. | |
121 | ;;; | |
122 | ||
123 | (define-record-type <request> | |
124 | (make-request method uri version headers port) | |
125 | request? | |
126 | (method request-method) | |
127 | (uri request-uri) | |
128 | (version request-version) | |
129 | (headers request-headers) | |
130 | (port request-port)) | |
131 | ||
132 | (define (bad-request message . args) | |
133 | (throw 'bad-request message args)) | |
134 | ||
135 | (define (non-negative-integer? n) | |
136 | (and (number? n) (>= n 0) (exact? n) (integer? n))) | |
137 | ||
138 | (define (validate-headers headers) | |
139 | (if (pair? headers) | |
140 | (let ((h (car headers))) | |
141 | (if (pair? h) | |
142 | (let ((k (car h)) (v (cdr h))) | |
143 | (if (symbol? k) | |
144 | (if (not (valid-header? k v)) | |
145 | (bad-request "Bad value for header ~a: ~s" k v)) | |
146 | (if (not (and (string? k) (string? v))) | |
147 | (bad-request "Unknown header not a pair of strings: ~s" | |
148 | h))) | |
149 | (validate-headers (cdr headers))) | |
150 | (bad-request "Header not a pair: ~a" h))) | |
151 | (if (not (null? headers)) | |
152 | (bad-request "Headers not a list: ~a" headers)))) | |
153 | ||
154 | (define* (build-request #:key (method 'GET) uri (version '(1 . 1)) | |
155 | (headers '()) port (validate-headers? #t)) | |
156 | (cond | |
157 | ((not (and (pair? version) | |
158 | (non-negative-integer? (car version)) | |
159 | (non-negative-integer? (cdr version)))) | |
160 | (bad-request "Bad version: ~a" version)) | |
161 | ((not (uri? uri)) | |
162 | (bad-request "Bad uri: ~a" uri)) | |
163 | ((and (not port) (memq method '(POST PUT))) | |
164 | (bad-request "Missing port for message ~a" method)) | |
165 | (else | |
166 | (if validate-headers? | |
167 | (validate-headers headers)))) | |
168 | (make-request method uri version headers port)) | |
169 | ||
170 | (define (read-request port) | |
171 | (set-port-encoding! port "ISO-8859-1") | |
172 | (call-with-values (lambda () (read-request-line port)) | |
173 | (lambda (method uri version) | |
174 | (make-request method uri version (read-headers port) port)))) | |
175 | ||
176 | (define (write-request r port) | |
177 | (write-request-line (request-method r) (request-uri r) | |
178 | (request-version r) port) | |
179 | (write-headers (request-headers r) port) | |
180 | (display "\r\n" port) | |
181 | (if (eq? port (request-port r)) | |
182 | r | |
183 | (make-request (request-method r) (request-uri r) (request-version r) | |
184 | (request-headers r) port))) | |
185 | ||
186 | ;; Probably not what you want to use "in production". Relies on one byte | |
187 | ;; per char because we are in latin-1 encoding. | |
188 | ;; | |
189 | (define (read-request-body/latin-1 r) | |
190 | (let ((nbytes (request-content-length r))) | |
191 | (and nbytes | |
192 | (let ((buf (make-string nbytes))) | |
193 | (read-delimited! "" buf (request-port r)) | |
194 | buf)))) | |
195 | ||
196 | ;; Likewise, assumes that body can be written in the latin-1 encoding, | |
197 | ;; and that the latin-1 encoding is what is expected by the server. | |
198 | ;; | |
199 | (define (write-request-body/latin-1 r body) | |
200 | (display body (request-port r))) | |
201 | ||
202 | (define (read-request-body/bytevector r) | |
203 | (let ((nbytes (request-content-length r))) | |
204 | (and nbytes | |
205 | (let ((bv (get-bytevector-n (request-port r) nbytes))) | |
206 | (if (= (bytevector-length bv) nbytes) | |
207 | bv | |
208 | (bad-request "EOF while reading request body: ~a bytes of ~a" | |
209 | (bytevector-length bv) nbytes)))))) | |
210 | ||
211 | (define (write-request-body/bytevector r bv) | |
212 | (put-bytevector (request-port r) bv)) | |
213 | ||
214 | (define-syntax define-request-accessor | |
215 | (lambda (x) | |
216 | (syntax-case x () | |
217 | ((_ field) | |
218 | #'(define-request-accessor field #f)) | |
219 | ((_ field def) (identifier? #'field) | |
220 | #`(define* (#,(datum->syntax | |
221 | #'field | |
222 | (symbol-append 'request- (syntax->datum #'field))) | |
223 | request | |
224 | #:optional (default def)) | |
225 | (cond | |
226 | ((assq 'field (request-headers request)) => cdr) | |
227 | (else default))))))) | |
228 | ||
229 | ;; General headers | |
230 | ;; | |
231 | (define-request-accessor cache-control '()) | |
232 | (define-request-accessor connection '()) | |
233 | (define-request-accessor date #f) | |
234 | (define-request-accessor pragma '()) | |
235 | (define-request-accessor trailer '()) | |
236 | (define-request-accessor transfer-encoding '()) | |
237 | (define-request-accessor upgrade '()) | |
238 | (define-request-accessor via '()) | |
239 | (define-request-accessor warning '()) | |
240 | ||
241 | ;; Entity headers | |
242 | ;; | |
243 | (define-request-accessor allow '()) | |
244 | (define-request-accessor content-encoding '()) | |
245 | (define-request-accessor content-language '()) | |
246 | (define-request-accessor content-length #f) | |
247 | (define-request-accessor content-location #f) | |
248 | (define-request-accessor content-md5 #f) | |
249 | (define-request-accessor content-range #f) | |
250 | (define-request-accessor content-type #f) | |
251 | (define-request-accessor expires #f) | |
252 | (define-request-accessor last-modified #f) | |
253 | ||
254 | ;; Request headers | |
255 | ;; | |
256 | (define-request-accessor accept '()) | |
257 | (define-request-accessor accept-charset '()) | |
258 | (define-request-accessor accept-encoding '()) | |
259 | (define-request-accessor accept-language '()) | |
260 | (define-request-accessor authorization #f) | |
261 | (define-request-accessor expect '()) | |
262 | (define-request-accessor from #f) | |
263 | (define-request-accessor host #f) | |
264 | ;; Absence of an if-directive appears to be different from `*'. | |
265 | (define-request-accessor if-match #f) | |
266 | (define-request-accessor if-modified-since #f) | |
267 | (define-request-accessor if-none-match #f) | |
268 | (define-request-accessor if-range #f) | |
269 | (define-request-accessor if-unmodified-since #f) | |
270 | (define-request-accessor max-forwards #f) | |
271 | (define-request-accessor proxy-authorization #f) | |
272 | (define-request-accessor range #f) | |
273 | (define-request-accessor referer #f) | |
274 | (define-request-accessor te '()) | |
275 | (define-request-accessor user-agent #f) | |
276 | ||
277 | ;; Misc accessors | |
278 | (define* (request-absolute-uri r #:optional default-host default-port) | |
279 | (let ((uri (request-uri r))) | |
280 | (if (uri-host uri) | |
281 | uri | |
282 | (let ((host | |
283 | (or (request-host r) | |
284 | (if default-host | |
285 | (cons default-host default-port) | |
286 | (bad-request | |
287 | "URI not absolute, no Host header, and no default: ~s" | |
288 | uri))))) | |
289 | (build-uri (uri-scheme uri) | |
290 | #:host (car host) | |
291 | #:port (cdr host) | |
292 | #:path (uri-path uri) | |
293 | #:query (uri-query uri) | |
294 | #:fragment (uri-fragment uri)))))) |