http_req.c

完整实现http协议源代码（WINDOWS或LINUX平台均可移植使用）,我在VC++上(不调用WINDOWS的HTTP的API)可实现XML文件下载等.

/*
 * http_req.c -- Functions for making http requests
 * Created: Christopher Blizzard <[e-mail]>, 6-Aug-1998
 *
 * Copyright (C) 1998 Free Software Foundation
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Library General Public
 * License as published by the Free Software Foundation; either
 * version 2 of the License, or (at your option) any later version.
 *
 * This library 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
 * Library General Public License for more details.
 *
 * You should have received a copy of the GNU Library General Public
 * License along with this library; if not, write to the Free
 * Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 */

#include <string.h>
#include <stdlib.h>
#include "http_req.h"
#include "http_trans.h"
#include "http_global.h"

const char *
http_req_type_char[] = {
  "GET",
  "OPTIONS",
  "HEAD",
  "POST",
  "PUT",
  "DELETE",
  "TRACE",
  "CONNECT",
  "PROPFIND",
  "PROPPATCH",
  "MKCOL",
  "COPY",
  "MOVE",
  "LOCK",
  "UNLOCK",
  NULL
};

http_req *
http_req_new(void)
{
  http_req *l_return = NULL;
  
  l_return = (http_req *)malloc(sizeof(http_req));
  memset(l_return, 0, sizeof(http_req));
  /* default to 1.1 */
  l_return->http_ver = 1.1;
  l_return->headers = http_hdr_list_new();
  return l_return;
}

void
http_req_destroy(http_req *a_req)
{
  if (!a_req)
    return;
  if (a_req->headers)
    http_hdr_list_destroy(a_req->headers);
  free(a_req);
}

int
http_req_prepare(http_req *a_req)
{
  int l_return = 0;
  char l_buf[30];

  if (!a_req)
    return -1;
  memset(l_buf, 0, 30);
  /* set the host header */
  http_hdr_set_value(a_req->headers,
		     http_hdr_Host,
		     a_req->host);
  /* check to see if we have an entity body */
  if ((a_req->type == http_req_type_post) ||
      (a_req->type == http_req_type_put) ||
      (a_req->type == http_req_type_trace))
    {
      sprintf(l_buf, "%d", a_req->body_len);
      http_hdr_set_value(a_req->headers,
			 http_hdr_Content_Length,
			 l_buf);
    }
  /* if the user agent isn't set then set a default */
  if (http_hdr_get_value(a_req->headers, http_hdr_User_Agent) == NULL)
    http_hdr_set_value(a_req->headers, http_hdr_User_Agent,
		       "libghttp/1.0");
  return l_return;
}

int
http_req_send(http_req *a_req, http_trans_conn *a_conn)
{
  char       *l_request = NULL;
  int         l_request_len = 0;
  int         i = 0;
  int         l_len = 0;
  int         l_headers_len = 0;
  int         l_rv = 0;
  char       *l_content = NULL;

  /* see if we need to jump into the function somewhere */
  if (a_conn->sync == HTTP_TRANS_ASYNC)
    {
      if (a_req->state == http_req_state_sending_request)
	goto http_req_state_sending_request_jump;
      if (a_req->state == http_req_state_sending_headers)
	goto http_req_state_sending_headers_jump;
      if (a_req->state == http_req_state_sending_body)
	goto http_req_state_sending_body_jump;
    }
  /* enough for the request and the other little headers */
  l_request = malloc(30 + strlen(a_req->resource) + (a_conn->proxy_host ?
						     (strlen(a_req->host) + 20) : 0));
  memset(l_request, 0, 30 + strlen(a_req->resource) + (a_conn->proxy_host ?
						       (strlen(a_req->host) + 20) : 0));
  /* copy it into the buffer */
  if (a_conn->proxy_host)
    {
      l_request_len = sprintf(l_request,
			      "%s %s HTTP/%01.1f\r\n",
			      http_req_type_char[a_req->type],
			      a_req->full_uri,
			      a_req->http_ver);
    }
  else
    {
      l_request_len = sprintf(l_request,
			      "%s %s HTTP/%01.1f\r\n",
			      http_req_type_char[a_req->type],
			      a_req->resource,
			      a_req->http_ver);
    }
  /* set the request in the connection buffer */
  http_trans_append_data_to_buf(a_conn, l_request, l_request_len);
  /* free up the request - we don't need it anymore */
  free(l_request);
  l_request = NULL;
  /* set the state */
  a_req->state = http_req_state_sending_request;
 http_req_state_sending_request_jump:
  /* send the request */
  do {
    l_rv = http_trans_write_buf(a_conn);
    if ((a_conn->sync == HTTP_TRANS_ASYNC) && (l_rv == HTTP_TRANS_NOT_DONE))
      return HTTP_TRANS_NOT_DONE;
    if ((l_rv == HTTP_TRANS_DONE) && (a_conn->last_read == 0))
      return HTTP_TRANS_ERR;
  } while (l_rv == HTTP_TRANS_NOT_DONE);
  /* reset the buffer */
  http_trans_buf_reset(a_conn);
  /* set up all of the headers */
  for (i = 0; i < HTTP_HDRS_MAX; i++)
    {
      l_len = 0;
      if (a_req->headers->header[i])
	{
	  l_len = strlen(a_req->headers->header[i]);
	  if (l_len > 0)
	    {
	      http_trans_append_data_to_buf(a_conn, a_req->headers->header[i], l_len);
	      l_headers_len += l_len;
	      http_trans_append_data_to_buf(a_conn, ": ", 2);
	      l_headers_len += 2;
	      /* note, it's ok to have no value for a request */
	      if ((l_len = strlen(a_req->headers->value[i])) > 0)
		{
		  http_trans_append_data_to_buf(a_conn, a_req->headers->value[i], l_len);
		  l_headers_len += l_len;
		}
	      http_trans_append_data_to_buf(a_conn, "\r\n", 2);
	      l_headers_len += 2;
	    }
	}
    }
  http_trans_append_data_to_buf(a_conn, "\r\n", 2);
  l_headers_len += 2;
  /* set the state */
  a_req->state = http_req_state_sending_headers;
 http_req_state_sending_headers_jump:
  /* blast that out to the network */
  do {
    l_rv = http_trans_write_buf(a_conn);
    if ((a_conn->sync == HTTP_TRANS_ASYNC) && (l_rv == HTTP_TRANS_NOT_DONE))
      return HTTP_TRANS_NOT_DONE;
    if ((l_rv == HTTP_TRANS_DONE) && (a_conn->last_read == 0))
      return HTTP_TRANS_ERR;
  } while (l_rv == HTTP_TRANS_NOT_DONE);
  /* reset the buffer */
  http_trans_buf_reset(a_conn);
  l_content = http_hdr_get_value(a_req->headers, http_hdr_Content_Length);
  if (l_content)
    {
      /* append the information to the buffer */
      http_trans_append_data_to_buf(a_conn, a_req->body, a_req->body_len);
      a_req->state = http_req_state_sending_body;
    http_req_state_sending_body_jump:
      do {
	l_rv = http_trans_write_buf(a_conn);
	if ((a_conn->sync == HTTP_TRANS_ASYNC) && (l_rv == HTTP_TRANS_NOT_DONE))
	  return HTTP_TRANS_NOT_DONE;
	if ((l_rv == HTTP_TRANS_DONE) && (a_conn->last_read == 0))
	  return HTTP_TRANS_ERR;
      } while (l_rv == HTTP_TRANS_NOT_DONE);
      /* reset the buffer */
      http_trans_buf_reset(a_conn);
    }
  return HTTP_TRANS_DONE;
}