jscoverage/trunk/http-exchange.c

/*
    http-exchange.c - HTTP request/response exchange
    Copyright (C) 2008 siliconforks.com

    This program is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation; either version 2 of the License, or
    (at your option) any later version.

    This program 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 General Public License for more details.

    You should have received a copy of the GNU General Public License along
    with this program; if not, write to the Free Software Foundation, Inc.,
    51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
*/

#include <config.h>

#include "http-server.h"

#include <assert.h>
#include <ctype.h>
#include <string.h>

#include "util.h"

struct HTTPExchange {
  HTTPConnection * connection;

  HTTPMessage * request_message;

  char * method;
  char * request_uri;
  char * request_http_version;

  char * host;
  uint16_t port;
  char * abs_path;
  char * query;

  HTTPMessage * response_message;

  uint16_t status_code;
  char * response_http_version;
};

static const struct {
  const int status_code;
  const char * const reason_phrase;
} reason_phrases[] = {
  {100, "Continue"},
  {101, "Switching Protocols"},
  {200, "OK"},
  {201, "Created"},
  {202, "Accepted"},
  {203, "Non-Authoritative Information"},
  {204, "No Content"},
  {205, "Reset Content"},
  {206, "Partial Content"},
  {301, "Moved Permanently"},
  {302, "Found"},
  {303, "See Other"},
  {304, "Not Modified"},
  {305, "Use Proxy"},
  {307, "Temporary Redirect"},
  {400, "Bad Request"},
  {401, "Unauthorized"},
  {402, "Payment Required"},
  {403, "Forbidden"},
  {404, "Not Found"},
  {405, "Method Not Allowed"},
  {406, "Not Acceptable"},
  {407, "Proxy Authentication Required"},
  {408, "Request Time-out"},
  {409, "Conflict"},
  {410, "Gone"},
  {411, "Length Required"},
  {412, "Precondition Failed"},
  {413, "Request Entity Too Large"},
  {414, "Request-URI Too Large"},
  {415, "Unsupported Media Type"},
  {416, "Requested range not satisfiable"},
  {417, "Expectation Failed"},
  {500, "Internal Server Error"},
  {501, "Not Implemented"},
  {502, "Bad Gateway"},
  {503, "Service Unavailable"},
  {504, "Gateway Time-out"},
  {505, "HTTP Version not supported"},
};

HTTPExchange * HTTPExchange_new(HTTPConnection * connection) {
  HTTPExchange * exchange = xmalloc(sizeof(HTTPExchange));

  exchange->connection = connection;

  exchange->request_message = HTTPMessage_new(connection);
  exchange->method = NULL;
  exchange->request_uri = NULL;
  exchange->request_http_version = NULL;
  exchange->host = NULL;
  exchange->port = 0;
  exchange->abs_path = NULL;
  exchange->query = NULL;

  exchange->response_message = HTTPMessage_new(connection);
  exchange->response_http_version = NULL;
  exchange->status_code = 0;

  return exchange;
}

void HTTPExchange_delete(HTTPExchange * exchange) {
  HTTPMessage_delete(exchange->response_message);
  free(exchange->response_http_version);

  HTTPMessage_delete(exchange->request_message);
  free(exchange->method);
  free(exchange->request_uri);
  free(exchange->request_http_version);
  free(exchange->host);
  free(exchange->abs_path);
  free(exchange->query);

  free(exchange);
}

int HTTPExchange_get_peer(const HTTPExchange * exchange, struct sockaddr_in * peer) {
  return HTTPConnection_get_peer(exchange->connection, peer);
}

HTTPMessage * HTTPExchange_get_request_message(const HTTPExchange * exchange) {
  return exchange->request_message;
}

const char * HTTPExchange_get_request_line(const HTTPExchange * exchange) {
  return HTTPMessage_get_start_line(exchange->request_message);
}

const char * HTTPExchange_get_method(const HTTPExchange * exchange) {
  return exchange->method;
}

const char * HTTPExchange_get_request_uri(const HTTPExchange * exchange) {
  return exchange->request_uri;
}

const char * HTTPExchange_get_request_http_version(const HTTPExchange * exchange) {
  return exchange->request_http_version;
}

const char * HTTPExchange_get_host(const HTTPExchange * exchange) {
  return exchange->host;
}

uint16_t HTTPExchange_get_port(const HTTPExchange * exchange) {
  return exchange->port;
}

const char * HTTPExchange_get_abs_path(const HTTPExchange * exchange) {
  return exchange->abs_path;
}

void HTTPExchange_set_method(HTTPExchange * exchange, const char * method) {
  free(exchange->method);
  exchange->method = xstrdup(method);
}

void HTTPExchange_set_request_uri(HTTPExchange * exchange, const char * request_uri) {
  free(exchange->request_uri);
  exchange->request_uri = xstrdup(request_uri);
}

const HTTPHeader * HTTPExchange_get_request_headers(const HTTPExchange * exchange) {
  return HTTPMessage_get_headers(exchange->request_message);
}

const char * HTTPExchange_find_request_header(const HTTPExchange * exchange, const char * name) {
  return HTTPMessage_find_header(exchange->request_message, name);
}

void HTTPExchange_add_request_header(HTTPExchange * exchange, const char * name, const char * value) {
  HTTPMessage_add_header(exchange->request_message, name, value);
}

void HTTPExchange_set_request_header(HTTPExchange * exchange, const char * name, const char * value) {
  HTTPMessage_set_header(exchange->request_message, name, value);
}

void HTTPExchange_set_request_content_length(HTTPExchange * exchange, size_t value) {
  HTTPMessage_set_content_length(exchange->request_message, value);
}

int HTTPExchange_read_request_headers(HTTPExchange * exchange) {
  int result = 0;

  result = HTTPMessage_read_start_line_and_headers(exchange->request_message);
  if (result != 0) {
    return result;
  }

  /* parse the Request-Line */
  const char * request_line = HTTPMessage_get_start_line(exchange->request_message);
  const char * p = request_line;

  /* parse the Method */
  while (*p != ' ') {
    if (*p == '\0') {
      return -1;
    }
    p++;
  }
  if (p == request_line) {
    return -1;
  }
  exchange->method = xstrndup(request_line, p - request_line);

  /* skip over space */
  p++;

  /* parse the Request-URI */
  const char * start = p;
  while (*p != ' ') {
    if (*p == '\0') {
      return -1;
    }
    p++;
  }
  if (p == start) {
    return -1;
  }
  exchange->request_uri = xstrndup(start, p - start);

  /* skip over space */
  p++;

  /* parse the HTTP-Version */
  start = p;
  while (*p != '\r' && *p != '\n') {
    if (*p == '\0') {
      return -1;
    }
    p++;
  }
  if (p == start) {
    return -1;
  }
  exchange->request_http_version = xstrndup(start, p - start);

  /* uri elements */
  /* RFC 2616 5.1.2: the Request-URI can be an `absoluteURI' or an `abs_path' */
  result = URL_parse(exchange->request_uri, &(exchange->host), &(exchange->port),
                                            &(exchange->abs_path), &(exchange->query));
  if (result != 0) {
    return result;
  }

  if (exchange->host == NULL) {
    /* abs_path */
    const char * h = HTTPMessage_find_header(exchange->request_message, HTTP_HOST);
    if (h == NULL) {
      /* this must be an HTTP/1.0 client */
    }
    else {
      result = URL_parse_host_and_port(h, &(exchange->host), &(exchange->port));
      if (result != 0) {
        return result;
      }
    }
  }

  return 0;
}

int HTTPExchange_write_request_headers(HTTPExchange * exchange) {
  if (HTTPMessage_has_sent_headers(exchange->request_message)) {
    return 0;
  }

  /* set the Request-Line */
  if (HTTPMessage_get_start_line(exchange->request_message) == NULL) {
    if (exchange->method == NULL) {
      exchange->method = xstrdup("GET");
    }
    assert(exchange->request_uri != NULL);
    char * request_line;
    xasprintf(&request_line, "%s %s HTTP/1.1\r\n", exchange->method, exchange->request_uri);
    HTTPMessage_set_start_line(exchange->request_message, request_line);
    free(request_line);
  }

  /* set the Host, if necessary */
  if (! str_starts_with(exchange->request_uri, "http://")) {
    const char * host = HTTPMessage_find_header(exchange->request_message, HTTP_HOST);
    if (host == NULL) {
      struct sockaddr_in peer;
      int result = HTTPConnection_get_peer(exchange->connection, &peer);
      if (result != 0) {
        return result;
      }
      const char * a = inet_ntoa(peer.sin_addr);
      char * value;
      xasprintf(&value, "%s:%u", a, ntohs(peer.sin_port));
      HTTPMessage_add_header(exchange->request_message, HTTP_HOST, value);
      free(value);
    }
  }

  return HTTPMessage_write_start_line_and_headers(exchange->request_message);
}

bool HTTPExchange_request_has_body(const HTTPExchange * exchange) {
  /*
  RFC 2616 4.3: a request has a body iff the request has a Content-Length or Transfer-Encoding header
  */
  return HTTPMessage_find_header(exchange->request_message, HTTP_CONTENT_LENGTH) != NULL || 
         HTTPMessage_find_header(exchange->request_message, HTTP_TRANSFER_ENCODING) != NULL;
}

int HTTPExchange_read_entire_request_entity_body(HTTPExchange * exchange, Stream * stream) {
  return HTTPMessage_read_entire_entity_body(exchange->request_message, stream);
}

int HTTPExchange_flush_request(HTTPExchange * exchange) {
  return HTTPMessage_flush(exchange->request_message);
}

/* response methods */

HTTPMessage * HTTPExchange_get_response_message(const HTTPExchange * exchange) {
  return exchange->response_message;
}

const char * HTTPExchange_get_response_http_version(const HTTPExchange * exchange) {
  return exchange->response_http_version;
}

uint16_t HTTPExchange_get_status_code(const HTTPExchange * exchange) {
  return exchange->status_code;
}

void HTTPExchange_set_status_code(HTTPExchange * exchange, uint16_t status_code) {
  exchange->status_code = status_code;
}

const HTTPHeader * HTTPExchange_get_response_headers(const HTTPExchange * exchange) {
  return HTTPMessage_get_headers(exchange->response_message);
}

const char * HTTPExchange_find_response_header(const HTTPExchange * exchange, const char * name) {
  return HTTPMessage_find_header(exchange->response_message, name);
}

void HTTPExchange_add_response_header(HTTPExchange * exchange, const char * name, const char * value) {
  HTTPMessage_add_header(exchange->response_message, name, value);
}

void HTTPExchange_set_response_header(HTTPExchange * exchange, const char * name, const char * value) {
  HTTPMessage_set_header(exchange->response_message, name, value);
}

void HTTPExchange_set_response_content_length(HTTPExchange * exchange, size_t value) {
  HTTPMessage_set_content_length(exchange->response_message, value);
}

static void skip_digits(const char ** p) {
  while (**p != '\0' && isdigit(**p)) {
    (*p)++;
  }
}

int HTTPExchange_read_response_headers(HTTPExchange * exchange) {
  /* make sure the request went through before we try to read stuff */
  int result = HTTPExchange_flush_request(exchange);
  if (result != 0) {
    return result;
  }

  result = HTTPMessage_read_start_line_and_headers(exchange->response_message);
  if (result != 0) {
    return result;
  }

  /* parse the Status-Line (RFC 2616 6.1) */
  const char * status_line = HTTPMessage_get_start_line(exchange->response_message);
  const char * p = status_line;

  /* read the HTTP-Version */
  if (! str_starts_with(p, "HTTP/")) {
    return -1;
  }
  p += 5;
  const char * start = p;
  skip_digits(&p);
  if (start == p) {
    return -1;
  }
  if (*p != '.') {
    return -1;
  }
  p++;
  start = p;
  skip_digits(&p);
  if (start == p) {
    return -1;
  }
  if (*p != ' ') {
    return -1;
  }
  exchange->response_http_version = xstrndup(status_line, p - status_line);

  /* skip over the space */
  p++;

  /* read the Status-Code */
  start = p;
  skip_digits(&p);
  if (p - start != 3) {
    return -1;
  }
  if (*p != ' ') {
    return -1;
  }
  exchange->status_code = strtoul(start, NULL, 10);

  return 0;
}

int HTTPExchange_write_response_headers(HTTPExchange * exchange) {
  if (HTTPMessage_has_sent_headers(exchange->response_message)) {
    return 0;
  }

  /* set the Status-Line (RFC 2616 6.1) */
  if (exchange->status_code == 0) {
    exchange->status_code = 200;
  }
  const char * reason_phrase = NULL;
  size_t num_reason_phrases = sizeof(reason_phrases) / sizeof(reason_phrases[0]);
  for (size_t i = 0; i < num_reason_phrases; i++) {
    if (reason_phrases[i].status_code == exchange->status_code) {
      reason_phrase = reason_phrases[i].reason_phrase;
      break;
    }
  }
  assert(reason_phrase != NULL);
  char * status_line;
  xasprintf(&status_line, "HTTP/1.1 %u %s\r\n", exchange->status_code, reason_phrase);
  HTTPMessage_set_start_line(exchange->response_message, status_line);
  free(status_line);

  /* set the Content-Type, if necessary */
  const char * content_type = HTTPMessage_find_header(exchange->response_message, HTTP_CONTENT_TYPE);
  if (content_type == NULL) {
    HTTPMessage_set_header(exchange->response_message, HTTP_CONTENT_TYPE, "text/html");
  }

  return HTTPMessage_write_start_line_and_headers(exchange->response_message);
}

bool HTTPExchange_response_has_body(const HTTPExchange * exchange) {
  /*
  RFC 2616 4.3: a response has a body iff the request is not HEAD and the response is not 1xx, 204, 304
  */
  const char * request_method = HTTPExchange_get_method(exchange);
  assert(request_method != NULL);
  return strcmp(request_method, "HEAD") != 0 &&
         exchange->status_code != 304 &&
         exchange->status_code != 204 &&
         exchange->status_code / 100 != 1;
}

int HTTPExchange_read_entire_response_entity_body(HTTPExchange * exchange, Stream * stream) {
  return HTTPMessage_read_entire_entity_body(exchange->response_message, stream);
}

int HTTPExchange_write_response(HTTPExchange * exchange, const void * p, size_t size) {
  int result = HTTPExchange_write_response_headers(exchange);
  if (result != 0) {
    return result;
  }
  return HTTPMessage_write(exchange->response_message, p, size);
}

int HTTPExchange_flush_response(HTTPExchange * exchange) {
  int result = HTTPExchange_write_response_headers(exchange);
  if (result != 0) {
    return result;
  }
  return HTTPMessage_flush(exchange->response_message);
}
1	siliconforks	116	/*
2			http-exchange.c - HTTP request/response exchange
3			Copyright (C) 2008 siliconforks.com
4
5			This program is free software; you can redistribute it and/or modify
6			it under the terms of the GNU General Public License as published by
7			the Free Software Foundation; either version 2 of the License, or
8			(at your option) any later version.
9
10			This program 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
13			GNU General Public License for more details.
14
15			You should have received a copy of the GNU General Public License along
16			with this program; if not, write to the Free Software Foundation, Inc.,
17			51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
18			*/
19
20			#include <config.h>
21
22			#include "http-server.h"
23
24			#include <assert.h>
25			#include <ctype.h>
26			#include <string.h>
27
28			#include "util.h"
29
30			struct HTTPExchange {
31			HTTPConnection * connection;
32
33			HTTPMessage * request_message;
34
35			char * method;
36			char * request_uri;
37			char * request_http_version;
38
39			char * host;
40			uint16_t port;
41			char * abs_path;
42			char * query;
43
44			HTTPMessage * response_message;
45
46			uint16_t status_code;
47			char * response_http_version;
48			};
49
50			static const struct {
51			const int status_code;
52			const char * const reason_phrase;
53			} reason_phrases[] = {
54			{100, "Continue"},
55			{101, "Switching Protocols"},
56			{200, "OK"},
57			{201, "Created"},
58			{202, "Accepted"},
59			{203, "Non-Authoritative Information"},
60			{204, "No Content"},
61			{205, "Reset Content"},
62			{206, "Partial Content"},
63			{301, "Moved Permanently"},
64			{302, "Found"},
65			{303, "See Other"},
66			{304, "Not Modified"},
67			{305, "Use Proxy"},
68			{307, "Temporary Redirect"},
69			{400, "Bad Request"},
70			{401, "Unauthorized"},
71			{402, "Payment Required"},
72			{403, "Forbidden"},
73			{404, "Not Found"},
74			{405, "Method Not Allowed"},
75			{406, "Not Acceptable"},
76			{407, "Proxy Authentication Required"},
77			{408, "Request Time-out"},
78			{409, "Conflict"},
79			{410, "Gone"},
80			{411, "Length Required"},
81			{412, "Precondition Failed"},
82			{413, "Request Entity Too Large"},
83			{414, "Request-URI Too Large"},
84			{415, "Unsupported Media Type"},
85			{416, "Requested range not satisfiable"},
86			{417, "Expectation Failed"},
87			{500, "Internal Server Error"},
88			{501, "Not Implemented"},
89			{502, "Bad Gateway"},
90			{503, "Service Unavailable"},
91			{504, "Gateway Time-out"},
92			{505, "HTTP Version not supported"},
93			};
94
95			HTTPExchange * HTTPExchange_new(HTTPConnection * connection) {
96			HTTPExchange * exchange = xmalloc(sizeof(HTTPExchange));
97
98			exchange->connection = connection;
99
100			exchange->request_message = HTTPMessage_new(connection);
101			exchange->method = NULL;
102			exchange->request_uri = NULL;
103			exchange->request_http_version = NULL;
104			exchange->host = NULL;
105			exchange->port = 0;
106			exchange->abs_path = NULL;
107			exchange->query = NULL;
108
109			exchange->response_message = HTTPMessage_new(connection);
110			exchange->response_http_version = NULL;
111			exchange->status_code = 0;
112
113			return exchange;
114			}
115
116			void HTTPExchange_delete(HTTPExchange * exchange) {
117			HTTPMessage_delete(exchange->response_message);
118			free(exchange->response_http_version);
119
120			HTTPMessage_delete(exchange->request_message);
121			free(exchange->method);
122			free(exchange->request_uri);
123			free(exchange->request_http_version);
124			free(exchange->host);
125			free(exchange->abs_path);
126			free(exchange->query);
127
128			free(exchange);
129			}
130
131			int HTTPExchange_get_peer(const HTTPExchange * exchange, struct sockaddr_in * peer) {
132			return HTTPConnection_get_peer(exchange->connection, peer);
133			}
134
135			HTTPMessage * HTTPExchange_get_request_message(const HTTPExchange * exchange) {
136			return exchange->request_message;
137			}
138
139			const char * HTTPExchange_get_request_line(const HTTPExchange * exchange) {
140			return HTTPMessage_get_start_line(exchange->request_message);
141			}
142
143			const char * HTTPExchange_get_method(const HTTPExchange * exchange) {
144			return exchange->method;
145			}
146
147			const char * HTTPExchange_get_request_uri(const HTTPExchange * exchange) {
148			return exchange->request_uri;
149			}
150
151			const char * HTTPExchange_get_request_http_version(const HTTPExchange * exchange) {
152			return exchange->request_http_version;
153			}
154
155			const char * HTTPExchange_get_host(const HTTPExchange * exchange) {
156			return exchange->host;
157			}
158
159			uint16_t HTTPExchange_get_port(const HTTPExchange * exchange) {
160			return exchange->port;
161			}
162
163			const char * HTTPExchange_get_abs_path(const HTTPExchange * exchange) {
164			return exchange->abs_path;
165			}
166
167			void HTTPExchange_set_method(HTTPExchange * exchange, const char * method) {
168			free(exchange->method);
169			exchange->method = xstrdup(method);
170			}
171
172			void HTTPExchange_set_request_uri(HTTPExchange * exchange, const char * request_uri) {
173			free(exchange->request_uri);
174			exchange->request_uri = xstrdup(request_uri);
175			}
176
177			const HTTPHeader * HTTPExchange_get_request_headers(const HTTPExchange * exchange) {
178			return HTTPMessage_get_headers(exchange->request_message);
179			}
180
181			const char * HTTPExchange_find_request_header(const HTTPExchange * exchange, const char * name) {
182			return HTTPMessage_find_header(exchange->request_message, name);
183			}
184
185			void HTTPExchange_add_request_header(HTTPExchange * exchange, const char * name, const char * value) {
186			HTTPMessage_add_header(exchange->request_message, name, value);
187			}
188
189			void HTTPExchange_set_request_header(HTTPExchange * exchange, const char * name, const char * value) {
190			HTTPMessage_set_header(exchange->request_message, name, value);
191			}
192
193			void HTTPExchange_set_request_content_length(HTTPExchange * exchange, size_t value) {
194			HTTPMessage_set_content_length(exchange->request_message, value);
195			}
196
197			int HTTPExchange_read_request_headers(HTTPExchange * exchange) {
198			int result = 0;
199
200			result = HTTPMessage_read_start_line_and_headers(exchange->request_message);
201			if (result != 0) {
202			return result;
203			}
204
205			/* parse the Request-Line */
206			const char * request_line = HTTPMessage_get_start_line(exchange->request_message);
207			const char * p = request_line;
208
209			/* parse the Method */
210			while (*p != ' ') {
211			if (*p == '\0') {
212			return -1;
213			}
214			p++;
215			}
216			if (p == request_line) {
217			return -1;
218			}
219			exchange->method = xstrndup(request_line, p - request_line);
220
221			/* skip over space */
222			p++;
223
224			/* parse the Request-URI */
225			const char * start = p;
226			while (*p != ' ') {
227			if (*p == '\0') {
228			return -1;
229			}
230			p++;
231			}
232			if (p == start) {
233			return -1;
234			}
235			exchange->request_uri = xstrndup(start, p - start);
236
237			/* skip over space */
238			p++;
239
240			/* parse the HTTP-Version */
241			start = p;
242			while (p != '\r' && p != '\n') {
243			if (*p == '\0') {
244			return -1;
245			}
246			p++;
247			}
248			if (p == start) {
249			return -1;
250			}
251			exchange->request_http_version = xstrndup(start, p - start);
252
253			/* uri elements */
254			/* RFC 2616 5.1.2: the Request-URI can be an `absoluteURI' or an `abs_path' */
255			result = URL_parse(exchange->request_uri, &(exchange->host), &(exchange->port),
256			&(exchange->abs_path), &(exchange->query));
257			if (result != 0) {
258			return result;
259			}
260
261			if (exchange->host == NULL) {
262			/* abs_path */
263			const char * h = HTTPMessage_find_header(exchange->request_message, HTTP_HOST);
264			if (h == NULL) {
265			/* this must be an HTTP/1.0 client */
266			}
267			else {
268			result = URL_parse_host_and_port(h, &(exchange->host), &(exchange->port));
269			if (result != 0) {
270			return result;
271			}
272			}
273			}
274
275			return 0;
276			}
277
278			int HTTPExchange_write_request_headers(HTTPExchange * exchange) {
279			if (HTTPMessage_has_sent_headers(exchange->request_message)) {
280			return 0;
281			}
282
283			/* set the Request-Line */
284			if (HTTPMessage_get_start_line(exchange->request_message) == NULL) {
285			if (exchange->method == NULL) {
286			exchange->method = xstrdup("GET");
287			}
288			assert(exchange->request_uri != NULL);
289			char * request_line;
290			xasprintf(&request_line, "%s %s HTTP/1.1\r\n", exchange->method, exchange->request_uri);
291			HTTPMessage_set_start_line(exchange->request_message, request_line);
292			free(request_line);
293			}
294
295			/* set the Host, if necessary */
296			if (! str_starts_with(exchange->request_uri, "http://")) {
297			const char * host = HTTPMessage_find_header(exchange->request_message, HTTP_HOST);
298			if (host == NULL) {
299			struct sockaddr_in peer;
300			int result = HTTPConnection_get_peer(exchange->connection, &peer);
301			if (result != 0) {
302			return result;
303			}
304			const char * a = inet_ntoa(peer.sin_addr);
305			char * value;
306			xasprintf(&value, "%s:%u", a, ntohs(peer.sin_port));
307			HTTPMessage_add_header(exchange->request_message, HTTP_HOST, value);
308			free(value);
309			}
310			}
311
312			return HTTPMessage_write_start_line_and_headers(exchange->request_message);
313			}
314
315			bool HTTPExchange_request_has_body(const HTTPExchange * exchange) {
316			/*
317			RFC 2616 4.3: a request has a body iff the request has a Content-Length or Transfer-Encoding header
318			*/
319			return HTTPMessage_find_header(exchange->request_message, HTTP_CONTENT_LENGTH) != NULL \|\|
320			HTTPMessage_find_header(exchange->request_message, HTTP_TRANSFER_ENCODING) != NULL;
321			}
322
323			int HTTPExchange_read_entire_request_entity_body(HTTPExchange * exchange, Stream * stream) {
324			return HTTPMessage_read_entire_entity_body(exchange->request_message, stream);
325			}
326
327			int HTTPExchange_flush_request(HTTPExchange * exchange) {
328			return HTTPMessage_flush(exchange->request_message);
329			}
330
331			/* response methods */
332
333			HTTPMessage * HTTPExchange_get_response_message(const HTTPExchange * exchange) {
334			return exchange->response_message;
335			}
336
337			const char * HTTPExchange_get_response_http_version(const HTTPExchange * exchange) {
338			return exchange->response_http_version;
339			}
340
341			uint16_t HTTPExchange_get_status_code(const HTTPExchange * exchange) {
342			return exchange->status_code;
343			}
344
345			void HTTPExchange_set_status_code(HTTPExchange * exchange, uint16_t status_code) {
346			exchange->status_code = status_code;
347			}
348
349			const HTTPHeader * HTTPExchange_get_response_headers(const HTTPExchange * exchange) {
350			return HTTPMessage_get_headers(exchange->response_message);
351			}
352
353			const char * HTTPExchange_find_response_header(const HTTPExchange * exchange, const char * name) {
354			return HTTPMessage_find_header(exchange->response_message, name);
355			}
356
357			void HTTPExchange_add_response_header(HTTPExchange * exchange, const char * name, const char * value) {
358			HTTPMessage_add_header(exchange->response_message, name, value);
359			}
360
361			void HTTPExchange_set_response_header(HTTPExchange * exchange, const char * name, const char * value) {
362			HTTPMessage_set_header(exchange->response_message, name, value);
363			}
364
365			void HTTPExchange_set_response_content_length(HTTPExchange * exchange, size_t value) {
366			HTTPMessage_set_content_length(exchange->response_message, value);
367			}
368
369			static void skip_digits(const char ** p) {
370			while (p != '\0' && isdigit(p)) {
371			(*p)++;
372			}
373			}
374
375			int HTTPExchange_read_response_headers(HTTPExchange * exchange) {
376			/* make sure the request went through before we try to read stuff */
377			int result = HTTPExchange_flush_request(exchange);
378			if (result != 0) {
379			return result;
380			}
381
382			result = HTTPMessage_read_start_line_and_headers(exchange->response_message);
383			if (result != 0) {
384			return result;
385			}
386
387			/* parse the Status-Line (RFC 2616 6.1) */
388			const char * status_line = HTTPMessage_get_start_line(exchange->response_message);
389			const char * p = status_line;
390
391			/* read the HTTP-Version */
392			if (! str_starts_with(p, "HTTP/")) {
393			return -1;
394			}
395			p += 5;
396			const char * start = p;
397			skip_digits(&p);
398			if (start == p) {
399			return -1;
400			}
401			if (*p != '.') {
402			return -1;
403			}
404			p++;
405			start = p;
406			skip_digits(&p);
407			if (start == p) {
408			return -1;
409			}
410			if (*p != ' ') {
411			return -1;
412			}
413			exchange->response_http_version = xstrndup(status_line, p - status_line);
414
415			/* skip over the space */
416			p++;
417
418			/* read the Status-Code */
419			start = p;
420			skip_digits(&p);
421			if (p - start != 3) {
422			return -1;
423			}
424			if (*p != ' ') {
425			return -1;
426			}
427			exchange->status_code = strtoul(start, NULL, 10);
428
429			return 0;
430			}
431
432			int HTTPExchange_write_response_headers(HTTPExchange * exchange) {
433			if (HTTPMessage_has_sent_headers(exchange->response_message)) {
434			return 0;
435			}
436
437			/* set the Status-Line (RFC 2616 6.1) */
438			if (exchange->status_code == 0) {
439			exchange->status_code = 200;
440			}
441			const char * reason_phrase = NULL;
442			size_t num_reason_phrases = sizeof(reason_phrases) / sizeof(reason_phrases[0]);
443			for (size_t i = 0; i < num_reason_phrases; i++) {
444			if (reason_phrases[i].status_code == exchange->status_code) {
445			reason_phrase = reason_phrases[i].reason_phrase;
446			break;
447			}
448			}
449			assert(reason_phrase != NULL);
450			char * status_line;
451			xasprintf(&status_line, "HTTP/1.1 %u %s\r\n", exchange->status_code, reason_phrase);
452			HTTPMessage_set_start_line(exchange->response_message, status_line);
453			free(status_line);
454
455			/* set the Content-Type, if necessary */
456			const char * content_type = HTTPMessage_find_header(exchange->response_message, HTTP_CONTENT_TYPE);
457			if (content_type == NULL) {
458			HTTPMessage_set_header(exchange->response_message, HTTP_CONTENT_TYPE, "text/html");
459			}
460
461			return HTTPMessage_write_start_line_and_headers(exchange->response_message);
462			}
463
464			bool HTTPExchange_response_has_body(const HTTPExchange * exchange) {
465			/*
466			RFC 2616 4.3: a response has a body iff the request is not HEAD and the response is not 1xx, 204, 304
467			*/
468			const char * request_method = HTTPExchange_get_method(exchange);
469			assert(request_method != NULL);
470			return strcmp(request_method, "HEAD") != 0 &&
471			exchange->status_code != 304 &&
472			exchange->status_code != 204 &&
473			exchange->status_code / 100 != 1;
474			}
475
476			int HTTPExchange_read_entire_response_entity_body(HTTPExchange * exchange, Stream * stream) {
477			return HTTPMessage_read_entire_entity_body(exchange->response_message, stream);
478			}
479
480			int HTTPExchange_write_response(HTTPExchange * exchange, const void * p, size_t size) {
481			int result = HTTPExchange_write_response_headers(exchange);
482			if (result != 0) {
483			return result;
484			}
485			return HTTPMessage_write(exchange->response_message, p, size);
486			}
487
488			int HTTPExchange_flush_response(HTTPExchange * exchange) {
489			int result = HTTPExchange_write_response_headers(exchange);
490			if (result != 0) {
491			return result;
492			}
493			return HTTPMessage_flush(exchange->response_message);
494			}