include/neon/ne_request.h

   1 /*
   2    HTTP Request Handling
   3    Copyright (C) 1999-2005, Joe Orton <joe@manyfish.co.uk>
   4
   5    This library is free software; you can redistribute it and/or
   6    modify it under the terms of the GNU Library General Public
   7    License as published by the Free Software Foundation; either
   8    version 2 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    Library General Public License for more details.
  14
  15    You should have received a copy of the GNU Library General Public
  16    License along with this library; if not, write to the Free
  17    Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,
  18    MA 02111-1307, USA
  19
  20 */
  21
  22 #ifndef NE_REQUEST_H
  23 #define NE_REQUEST_H
  24
  25 #include "ne_utils.h" /* For ne_status */
  26 #include "ne_string.h" /* For ne_buffer */
  27 #include "ne_session.h"
  28
  29 BEGIN_NEON_DECLS
  30
  31 #define NE_OK (0) /* Success */
  32 #define NE_ERROR (1) /* Generic error; use ne_get_error(session) for message */
  33 #define NE_LOOKUP (2) /* Server or proxy hostname lookup failed */
  34 #define NE_AUTH (3) /* User authentication failed on server */
  35 #define NE_PROXYAUTH (4) /* User authentication failed on proxy */
  36 #define NE_CONNECT (5) /* Could not connect to server */
  37 #define NE_TIMEOUT (6) /* Connection timed out */
  38 #define NE_FAILED (7) /* The precondition failed */
  39 #define NE_RETRY (8) /* Retry request (ne_end_request ONLY) */
  40 #define NE_REDIRECT (9) /* See ne_redirect.h */
  41
  42 /* Opaque object representing a single HTTP request. */
  43 typedef struct ne_request_s ne_request;
  44
  45 /***** Request Handling *****/
  46
  47 /* Create a request in session 'sess', with given method and path.
  48  * 'path' must conform to the 'abs_path' grammar in RFC2396, with an
  49  * optional "? query" part, and MUST be URI-escaped by the caller. */
  50 ne_request *ne_request_create(ne_session *sess,
  51                               const char *method, const char *path);
  52
  53 /* The request body will be taken from 'size' bytes of 'buffer'. */
  54 void ne_set_request_body_buffer(ne_request *req, const char *buffer,
  55                                 size_t size);
  56
  57 /* The request body will be taken from 'length' bytes read from the
  58  * file descriptor 'fd', starting from file offset 'offset'. */
  59 void ne_set_request_body_fd(ne_request *req, int fd,
  60                             off_t offset, off_t length);
  61
  62 #ifdef NE_LFS
  63 /* Alternate version of ne_set_request_body_fd taking off64_t
  64  * offset type for systems supporting _LARGEFILE64_SOURCE. */
  65 void ne_set_request_body_fd64(ne_request *req, int fd,
  66                               off64_t offset, off64_t length);
  67 #endif
  68
  69 /* "Pull"-based request body provider: a callback which is invoked to
  70  * provide blocks of request body on demand.
  71  *
  72  * Before each time the body is provided, the callback will be called
  73  * once with buflen == 0.  The body may have to be provided >1 time
  74  * per request (for authentication retries etc.).
  75  *
  76  * For a call with buflen == 0, the callback must return zero on success
  77  * or non-zero on error; the session error string must be set on error.
  78  * For a call with buflen > 0, the callback must return:
  79  *        <0           : error, abort request; session error string must be set.
  80  *         0           : ignore 'buffer' contents, end of body.
  81  *     0 < x <= buflen : buffer contains x bytes of body data.  */
  82 typedef ssize_t (*ne_provide_body)(void *userdata,
  83                                    char *buffer, size_t buflen);
  84
  85 /* Install a callback which is invoked as needed to provide the
  86  * request body, a block at a time.  The total size of the request
  87  * body is 'length'; the callback must ensure that it returns no more
  88  * than 'length' bytes in total. */
  89 void ne_set_request_body_provider(ne_request *req, off_t length,
  90                                   ne_provide_body provider, void *userdata);
  91
  92 #ifdef NE_LFS
  93 /* Duplicate version of ne_set_request_body_provider, taking an off64_t
  94  * offset. */
  95 void ne_set_request_body_provider64(ne_request *req, off64_t length,
  96                                     ne_provide_body provider, void *userdata);
  97 #endif
  98
  99 /* Handling response bodies; two callbacks must be provided:
 100  *
 101  * 1) 'acceptance' callback: determines whether you want to handle the
 102  * response body given the response-status information, e.g., if you
 103  * only want 2xx responses, say so here.
 104  *
 105  * 2) 'reader' callback: passed blocks of the response-body as they
 106  * arrive, if the acceptance callback returned non-zero.  */
 107
 108 /* 'acceptance' callback type. Return non-zero to accept the response,
 109  * else zero to ignore it. */
 110 typedef int (*ne_accept_response)(void *userdata, ne_request *req,
 111                                   const ne_status *st);
 112
 113 /* An 'acceptance' callback which only accepts 2xx-class responses.
 114  * Ignores userdata. */
 115 int ne_accept_2xx(void *userdata, ne_request *req, const ne_status *st);
 116
 117 /* An acceptance callback which accepts all responses.  Ignores
 118  * userdata. */
 119 int ne_accept_always(void *userdata, ne_request *req, const ne_status *st);
 120
 121 /* Callback for reading a block of data.  Returns zero on success, or
 122  * non-zero on error.  If returning an error, the response will be
 123  * aborted and the callback will not be invoked again.  The request
 124  * dispatch (or ne_read_response_block call) will fail with NE_ERROR;
 125  * the session error string should have been set by the callback. */
 126 typedef int (*ne_block_reader)(void *userdata, const char *buf, size_t len);
 127
 128 /* Add a response reader for the given request, with the given
 129  * acceptance function. userdata is passed as the first argument to
 130  * the acceptance + reader callbacks.
 131  *
 132  * The acceptance callback is called once each time the request is
 133  * sent: it may be sent >1 time because of authentication retries etc.
 134  * For each time the acceptance callback is called, if it returns
 135  * non-zero, blocks of the response body will be passed to the reader
 136  * callback as the response is read.  After all the response body has
 137  * been read, the callback will be called with a 'len' argument of
 138  * zero.  */
 139 void ne_add_response_body_reader(ne_request *req, ne_accept_response accpt,
 140                                  ne_block_reader reader, void *userdata);
 141
 142 /* Retrieve the value of the response header field with given name;
 143  * returns NULL if no response header with given name was found.  The
 144  * return value is valid only until the next call to either
 145  * ne_request_destroy or ne_begin_request for this request. */
 146 const char *ne_get_response_header(ne_request *req, const char *name);
 147
 148 /* Iterator interface for response headers: if passed a NULL cursor,
 149  * returns the first header; if passed a non-NULL cursor pointer,
 150  * returns the next header.  The return value is a cursor pointer: if
 151  * it is non-NULL, *name and *value are set to the name and value of
 152  * the header field.  If the return value is NULL, no more headers are
 153  * found, *name and *value are undefined.
 154  *
 155  * The order in which response headers is returned is undefined.  Both
 156  * the cursor and name/value pointers are valid only until the next
 157  * call to either ne_request_destroy or ne_begin_request for this
 158  * request. */
 159 void *ne_response_header_iterate(ne_request *req, void *cursor,
 160                                  const char **name, const char **value);
 161
 162 /* Adds a header to the request with given name and value. */
 163 void ne_add_request_header(ne_request *req, const char *name,
 164                            const char *value);
 165 /* Adds a header to the request with given name, using printf-like
 166  * format arguments for the value. */
 167 void ne_print_request_header(ne_request *req, const char *name,
 168                              const char *format, ...)
 169     ne_attribute((format(printf, 3, 4)));
 170
 171 /* ne_request_dispatch: Sends the given request, and reads the
 172  * response.  Returns:
 173  *  - NE_OK if the request was sent and response read successfully
 174  *  - NE_AUTH, NE_PROXYAUTH for a server or proxy server authentication error
 175  *  - NE_CONNECT if connection could not be established
 176  *  - NE_TIMEOUT if an timeout occurred sending or reading from the server
 177  *  - NE_ERROR for other fatal dispatch errors
 178  * On any error, the session error string is set.  On success or
 179  * authentication error, the actual response-status can be retrieved using
 180  * ne_get_status(). */
 181 int ne_request_dispatch(ne_request *req);
 182
 183 /* Returns a pointer to the response status information for the given
 184  * request; pointer is valid until request object is destroyed. */
 185 const ne_status *ne_get_status(const ne_request *req) ne_attribute((const));
 186
 187 /* Returns pointer to session associated with request. */
 188 ne_session *ne_get_session(const ne_request *req) ne_attribute((const));
 189
 190 /* Destroy memory associated with request pointer */
 191 void ne_request_destroy(ne_request *req);
 192
 193 /* "Caller-pulls" request interface.  This is an ALTERNATIVE interface
 194  * to ne_request_dispatch: either use that, or do all this yourself:
 195  *
 196  * caller must call:
 197  *  1. ne_begin_request (fail if returns non-NE_OK)
 198  *  2. while(ne_read_response_block(...) > 0) ... loop ...;
 199  *     (fail if ne_read_response_block returns <0)
 200  *  3. ne_end_request
 201  *
 202  * ne_end_request and ne_begin_request both return an NE_* code; if
 203  * ne_end_request returns NE_RETRY, you must restart the loop from (1)
 204  * above. */
 205 int ne_begin_request(ne_request *req);
 206 int ne_end_request(ne_request *req);
 207
 208 /* Read a block of the response into the passed buffer of size 'buflen'.
 209  *
 210  * Returns:
 211  *  <0 - error, stop reading.
 212  *   0 - end of response
 213  *  >0 - number of bytes read into buffer.
 214  */
 215 ssize_t ne_read_response_block(ne_request *req, char *buffer, size_t buflen);
 216
 217 /* Read response blocks until end of response; exactly equivalent to
 218  * calling ne_read_response_block() until it returns 0.  Returns
 219  * non-zero on error. */
 220 int ne_discard_response(ne_request *req);
 221
 222 /* Read response blocks until end of response, writing content to the
 223  * given file descriptor.  Returns NE_ERROR on error. */
 224 int ne_read_response_to_fd(ne_request *req, int fd);
 225
 226 /* If 'flag' is non-zer, enable the HTTP/1.1 "Expect: 100-continue"
 227  * feature for the request, which allows the server to send an error
 228  * response before the request body is sent.  This should only be used
 229  * if the server is known to support the feature (not all HTTP/1.1
 230  * servers do); the request will time out and fail otherwise. */
 231 void ne_set_request_expect100(ne_request *req, int flag);
 232
 233 /**** Request hooks handling *****/
 234
 235 typedef void (*ne_free_hooks)(void *cookie);
 236
 237 /* Hook called when a create is created; passed the request method,
 238  * and the string used as the Request-URI (which may be an abs_path,
 239  * or an absoluteURI, depending on whether an HTTP proxy is in
 240  * use).  */
 241 typedef void (*ne_create_request_fn)(ne_request *req, void *userdata,
 242                                      const char *method, const char *requri);
 243 void ne_hook_create_request(ne_session *sess,
 244                             ne_create_request_fn fn, void *userdata);
 245
 246 /* Hook called before the request is sent.  'header' is the raw HTTP
 247  * header before the trailing CRLF is added: add in more here. */
 248 typedef void (*ne_pre_send_fn)(ne_request *req, void *userdata,
 249                                ne_buffer *header);
 250 void ne_hook_pre_send(ne_session *sess, ne_pre_send_fn fn, void *userdata);
 251
 252 /* Hook called after the request is dispatched (request sent, and
 253  * the entire response read).  If an error occurred reading the response,
 254  * this hook will not run.  May return:
 255  *  NE_OK     everything is okay
 256  *  NE_RETRY  try sending the request again.
 257  * anything else signifies an error, and the request is failed. The return
 258  * code is passed back the _dispatch caller, so the session error must
 259  * also be set appropriately (ne_set_error).
 260  */
 261 typedef int (*ne_post_send_fn)(ne_request *req, void *userdata,
 262                                const ne_status *status);
 263 void ne_hook_post_send(ne_session *sess, ne_post_send_fn fn, void *userdata);
 264
 265 /* Hook called when the function is destroyed. */
 266 typedef void (*ne_destroy_req_fn)(ne_request *req, void *userdata);
 267 void ne_hook_destroy_request(ne_session *sess,
 268                              ne_destroy_req_fn fn, void *userdata);
 269
 270 typedef void (*ne_destroy_sess_fn)(void *userdata);
 271 /* Hook called when the session is destroyed. */
 272 void ne_hook_destroy_session(ne_session *sess,
 273                              ne_destroy_sess_fn fn, void *userdata);
 274
 275 /* Store an opaque context for the request, 'priv' is returned by a
 276  * call to ne_request_get_private with the same ID. */
 277 void ne_set_request_private(ne_request *req, const char *id, void *priv);
 278 void *ne_get_request_private(ne_request *req, const char *id);
 279
 280 END_NEON_DECLS
 281
 282 #endif /* NE_REQUEST_H */