aboutsummaryrefslogtreecommitdiff
path: root/src/mhd/mhd_responses.c
blob: 45a9932d309d003528e084b2552cb49b859d2cc6 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
/*
  This file is part of TALER
  Copyright (C) 2014-2020 Taler Systems SA

  TALER is free software; you can redistribute it and/or modify it under the
  terms of the GNU Affero General Public License as published by the Free Software
  Foundation; either version 3, or (at your option) any later version.

  TALER is distributed in the hope that it will be useful, but WITHOUT ANY
  WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR
  A PARTICULAR PURPOSE.  See the GNU Affero General Public License for more details.

  You should have received a copy of the GNU Affero General Public License along with
  TALER; see the file COPYING.  If not, see <http://www.gnu.org/licenses/>
*/
/**
 * @file mhd_responses.c
 * @brief API for generating HTTP replies
 * @author Florian Dold
 * @author Benedikt Mueller
 * @author Christian Grothoff
 */
#include "platform.h"
#include <zlib.h>
#include "taler_util.h"
#include "taler_mhd_lib.h"


/**
 * Global options for response generation.
 */
static enum TALER_MHD_GlobalOptions TM_go;


/**
 * Set global options for response generation
 * within libtalermhd.
 *
 * @param go global options to use
 */
void
TALER_MHD_setup (enum TALER_MHD_GlobalOptions go)
{
  TM_go = go;
}


/**
 * Add headers we want to return in every response.
 * Useful for testing, like if we want to always close
 * connections.
 *
 * @param response response to modify
 */
void
TALER_MHD_add_global_headers (struct MHD_Response *response)
{
  if (0 != (TM_go & TALER_MHD_GO_FORCE_CONNECTION_CLOSE))
    GNUNET_break (MHD_YES ==
                  MHD_add_response_header (response,
                                           MHD_HTTP_HEADER_CONNECTION,
                                           "close"));
  /* The wallet, operating from a background page, needs CORS to
     be disabled otherwise browsers block access. */
  GNUNET_break (MHD_YES ==
                MHD_add_response_header (response,
                                         MHD_HTTP_HEADER_ACCESS_CONTROL_ALLOW_ORIGIN,
                                         "*"));
}


/**
 * Is HTTP body deflate compression supported by the client?
 *
 * @param connection connection to check
 * @return #MHD_YES if 'deflate' compression is allowed
 *
 * Note that right now we're ignoring q-values, which is technically
 * not correct, and also do not support "*" anywhere but in a line by
 * itself.  This should eventually be fixed, see also
 * https://www.w3.org/Protocols/rfc2616/rfc2616-sec14.html
 */
MHD_RESULT
TALER_MHD_can_compress (struct MHD_Connection *connection)
{
  const char *ae;
  const char *de;

  if (0 != (TM_go & TALER_MHD_GO_DISABLE_COMPRESSION))
    return MHD_NO;
  ae = MHD_lookup_connection_value (connection,
                                    MHD_HEADER_KIND,
                                    MHD_HTTP_HEADER_ACCEPT_ENCODING);
  if (NULL == ae)
    return MHD_NO;
  if (0 == strcmp (ae,
                   "*"))
    return MHD_YES;
  de = strstr (ae,
               "deflate");
  if (NULL == de)
    return MHD_NO;
  if ( ( (de == ae) ||
         (de[-1] == ',') ||
         (de[-1] == ' ') ) &&
       ( (de[strlen ("deflate")] == '\0') ||
         (de[strlen ("deflate")] == ',') ||
         (de[strlen ("deflate")] == ';') ) )
    return MHD_YES;
  return MHD_NO;
}


/**
 * Try to compress a response body.  Updates @a buf and @a buf_size.
 *
 * @param[in,out] buf pointer to body to compress
 * @param[in,out] buf_size pointer to initial size of @a buf
 * @return #MHD_YES if @a buf was compressed
 */
MHD_RESULT
TALER_MHD_body_compress (void **buf,
                         size_t *buf_size)
{
  Bytef *cbuf;
  uLongf cbuf_size;
  MHD_RESULT ret;

  cbuf_size = compressBound (*buf_size);
  cbuf = malloc (cbuf_size);
  if (NULL == cbuf)
    return MHD_NO;
  ret = compress (cbuf,
                  &cbuf_size,
                  (const Bytef *) *buf,
                  *buf_size);
  if ( (Z_OK != ret) ||
       (cbuf_size >= *buf_size) )
  {
    /* compression failed */
    free (cbuf);
    return MHD_NO;
  }
  free (*buf);
  *buf = (void *) cbuf;
  *buf_size = (size_t) cbuf_size;
  return MHD_YES;
}


/**
 * Make JSON response object.
 *
 * @param json the json object
 * @return MHD response object
 */
struct MHD_Response *
TALER_MHD_make_json (const json_t *json)
{
  struct MHD_Response *response;
  char *json_str;

  json_str = json_dumps (json,
                         JSON_INDENT (2));
  if (NULL == json_str)
  {
    GNUNET_break (0);
    return NULL;
  }
  response = MHD_create_response_from_buffer (strlen (json_str),
                                              json_str,
                                              MHD_RESPMEM_MUST_FREE);
  if (NULL == response)
  {
    free (json_str);
    GNUNET_break (0);
    return NULL;
  }
  TALER_MHD_add_global_headers (response);
  GNUNET_break (MHD_YES ==
                MHD_add_response_header (response,
                                         MHD_HTTP_HEADER_CONTENT_TYPE,
                                         "application/json"));
  return response;
}


/**
 * Send JSON object as response.
 *
 * @param connection the MHD connection
 * @param json the json object
 * @param response_code the http response code
 * @return MHD result code
 */
MHD_RESULT
TALER_MHD_reply_json (struct MHD_Connection *connection,
                      const json_t *json,
                      unsigned int response_code)
{
  struct MHD_Response *response;
  void *json_str;
  size_t json_len;
  MHD_RESULT is_compressed;

  json_str = json_dumps (json,
                         JSON_INDENT (2));
  if (NULL == json_str)
  {
    /**
     * This log helps to figure out which
     * function called this one and assert-failed.
     */
    TALER_LOG_ERROR ("Aborting json-packing for HTTP code: %u\n",
                     response_code);

    GNUNET_assert (0);
    return MHD_NO;
  }
  json_len = strlen (json_str);
  /* try to compress the body */
  is_compressed = MHD_NO;
  if (MHD_YES ==
      TALER_MHD_can_compress (connection))
    is_compressed = TALER_MHD_body_compress (&json_str,
                                             &json_len);
  response = MHD_create_response_from_buffer (json_len,
                                              json_str,
                                              MHD_RESPMEM_MUST_FREE);
  if (NULL == response)
  {
    free (json_str);
    GNUNET_break (0);
    return MHD_NO;
  }
  TALER_MHD_add_global_headers (response);
  GNUNET_break (MHD_YES ==
                MHD_add_response_header (response,
                                         MHD_HTTP_HEADER_CONTENT_TYPE,
                                         "application/json"));
  if (MHD_YES == is_compressed)
  {
    /* Need to indicate to client that body is compressed */
    if (MHD_NO ==
        MHD_add_response_header (response,
                                 MHD_HTTP_HEADER_CONTENT_ENCODING,
                                 "deflate"))
    {
      GNUNET_break (0);
      MHD_destroy_response (response);
      return MHD_NO;
    }
  }

  {
    MHD_RESULT ret;

    ret = MHD_queue_response (connection,
                              response_code,
                              response);
    MHD_destroy_response (response);
    return ret;
  }
}


/**
 * Send back a "204 No Content" response with headers
 * for the CORS pre-flight request.
 *
 * @param connection the MHD connection
 * @return MHD result code
 */
MHD_RESULT
TALER_MHD_reply_cors_preflight (struct MHD_Connection *connection)
{
  struct MHD_Response *response;

  response = MHD_create_response_from_buffer (0,
                                              NULL,
                                              MHD_RESPMEM_PERSISTENT);
  if (NULL == response)
    return MHD_NO;
  /* This adds the Access-Control-Allow-Origin header.
   * All endpoints of the exchange allow CORS. */
  TALER_MHD_add_global_headers (response);
  GNUNET_break (MHD_YES ==
                MHD_add_response_header (response,
                                         /* Not available as MHD constant yet */
                                         "Access-Control-Allow-Headers",
                                         "*"));

  {
    MHD_RESULT ret;

    ret = MHD_queue_response (connection,
                              MHD_HTTP_NO_CONTENT,
                              response);
    MHD_destroy_response (response);
    return ret;
  }
}


/**
 * Function to call to handle the request by building a JSON
 * reply from a format string and varargs.
 *
 * @param connection the MHD connection to handle
 * @param response_code HTTP response code to use
 * @param fmt format string for pack
 * @param ... varargs
 * @return MHD result code
 */
MHD_RESULT
TALER_MHD_reply_json_pack (struct MHD_Connection *connection,
                           unsigned int response_code,
                           const char *fmt,
                           ...)
{
  json_t *json;
  json_error_t jerror;

  {
    va_list argp;

    va_start (argp,
              fmt);
    json = json_vpack_ex (&jerror,
                          0,
                          fmt,
                          argp);
    va_end (argp);
  }

  if (NULL == json)
  {
    GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
                "Failed to pack JSON with format `%s': %s\n",
                fmt,
                jerror.text);
    GNUNET_break (0);
    return MHD_NO;
  }

  {
    MHD_RESULT ret;

    ret = TALER_MHD_reply_json (connection,
                                json,
                                response_code);
    json_decref (json);
    return ret;
  }
}


/**
 * Make JSON response object.
 *
 * @param fmt format string for pack
 * @param ... varargs
 * @return MHD response object
 */
struct MHD_Response *
TALER_MHD_make_json_pack (const char *fmt,
                          ...)
{
  json_t *json;
  json_error_t jerror;

  {
    va_list argp;

    va_start (argp, fmt);
    json = json_vpack_ex (&jerror,
                          0,
                          fmt,
                          argp);
    va_end (argp);
  }

  if (NULL == json)
  {
    GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
                "Failed to pack JSON with format `%s': %s\n",
                fmt,
                jerror.text);
    GNUNET_break (0);
    return MHD_NO;
  }

  {
    struct MHD_Response *response;

    response = TALER_MHD_make_json (json);
    json_decref (json);
    return response;
  }
}


/**
 * Create a response indicating an internal error.
 *
 * @param ec error code to return
 * @param hint hint about the internal error's nature
 * @return a MHD response object
 */
struct MHD_Response *
TALER_MHD_make_error (enum TALER_ErrorCode ec,
                      const char *hint)
{
  return TALER_MHD_make_json_pack ("{s:I, s:s}",
                                   "code", (json_int_t) ec,
                                   "hint", hint);
}


/**
 * Send a response indicating an error.
 *
 * @param connection the MHD connection to use
 * @param ec error code uniquely identifying the error
 * @param http_status HTTP status code to use
 * @param hint human readable hint about the error
 * @return a MHD result code
 */
MHD_RESULT
TALER_MHD_reply_with_error (struct MHD_Connection *connection,
                            unsigned int http_status,
                            enum TALER_ErrorCode ec,
                            const char *hint)
{
  return TALER_MHD_reply_json_pack (connection,
                                    http_status,
                                    "{s:I, s:s}",
                                    "code", (json_int_t) ec,
                                    "hint", hint);
}


/**
 * Send a response indicating that the request was too big.
 *
 * @param connection the MHD connection to use
 * @return a MHD result code
 */
MHD_RESULT
TALER_MHD_reply_request_too_large (struct MHD_Connection *connection)
{
  struct MHD_Response *response;

  response = MHD_create_response_from_buffer (0,
                                              NULL,
                                              MHD_RESPMEM_PERSISTENT);
  if (NULL == response)
    return MHD_NO;
  TALER_MHD_add_global_headers (response);

  {
    MHD_RESULT ret;

    ret = MHD_queue_response (connection,
                              MHD_HTTP_REQUEST_ENTITY_TOO_LARGE,
                              response);
    MHD_destroy_response (response);
    return ret;
  }
}


/**
 * Function to call to handle the request by sending
 * back a redirect to the AGPL source code.
 *
 * @param connection the MHD connection to handle
 * @param url where to redirect for the sources
 * @return MHD result code
 */
MHD_RESULT
TALER_MHD_reply_agpl (struct MHD_Connection *connection,
                      const char *url)
{
  const char *agpl =
    "This server is licensed under the Affero GPL. You will now be redirected to the source code.";
  struct MHD_Response *response;

  response = MHD_create_response_from_buffer (strlen (agpl),
                                              (void *) agpl,
                                              MHD_RESPMEM_PERSISTENT);
  if (NULL == response)
  {
    GNUNET_break (0);
    return MHD_NO;
  }
  TALER_MHD_add_global_headers (response);
  GNUNET_break (MHD_YES ==
                MHD_add_response_header (response,
                                         MHD_HTTP_HEADER_CONTENT_TYPE,
                                         "text/plain"));
  if (MHD_NO ==
      MHD_add_response_header (response,
                               MHD_HTTP_HEADER_LOCATION,
                               url))
  {
    GNUNET_break (0);
    MHD_destroy_response (response);
    return MHD_NO;
  }

  {
    MHD_RESULT ret;

    ret = MHD_queue_response (connection,
                              MHD_HTTP_FOUND,
                              response);
    MHD_destroy_response (response);
    return ret;
  }
}


/**
 * Function to call to handle the request by sending
 * back static data.
 *
 * @param connection the MHD connection to handle
 * @param http_status status code to return
 * @param mime_type content-type to use
 * @param body response payload
 * @param body_size number of bytes in @a body
 * @return MHD result code
 */
MHD_RESULT
TALER_MHD_reply_static (struct MHD_Connection *connection,
                        unsigned int http_status,
                        const char *mime_type,
                        const char *body,
                        size_t body_size)
{
  struct MHD_Response *response;

  response = MHD_create_response_from_buffer (body_size,
                                              (void *) body,
                                              MHD_RESPMEM_PERSISTENT);
  if (NULL == response)
  {
    GNUNET_break (0);
    return MHD_NO;
  }
  TALER_MHD_add_global_headers (response);
  if (NULL != mime_type)
    GNUNET_break (MHD_YES ==
                  MHD_add_response_header (response,
                                           MHD_HTTP_HEADER_CONTENT_TYPE,
                                           mime_type));
  {
    MHD_RESULT ret;

    ret = MHD_queue_response (connection,
                              http_status,
                              response);
    MHD_destroy_response (response);
    return ret;
  }
}


/* end of mhd_responses.c */