http.c

       so we return an error here */
    failf(data, "Empty reply from server");
    return CURLE_GOT_NOTHING;
  }

  return CURLE_OK;
}

void Curl_http_auth_stage(struct SessionHandle *data,
                          int stage)
{
  if(stage == 401)
    data->state.authwant = data->set.httpauth;
  else if(stage == 407)
    data->state.authwant = data->set.proxyauth;
  else
    return; /* bad input stage */
  data->state.authstage = stage;
  data->state.authavail = CURLAUTH_NONE;
}

CURLcode Curl_http(struct connectdata *conn)
{
  struct SessionHandle *data=conn->data;
  char *buf = data->state.buffer; /* this is a short cut to the buffer */
  CURLcode result=CURLE_OK;
  struct HTTP *http;
  struct Cookie *co=NULL; /* no cookies from start */
  char *ppath = conn->ppath; /* three previous function arguments */
  char *host = conn->name;
  const char *te = ""; /* tranfer-encoding */
  char *ptr;
  char *request;
  bool authdone=TRUE; /* if the authentication phase is done */
  Curl_HttpReq httpreq;  /* type of HTTP request */

  if(!conn->proto.http) {
    /* Only allocate this struct if we don't already have it! */

    http = (struct HTTP *)malloc(sizeof(struct HTTP));
    if(!http)
      return CURLE_OUT_OF_MEMORY;
    memset(http, 0, sizeof(struct HTTP));
    conn->proto.http = http;
  }
  else
    http = conn->proto.http;

  /* We default to persistant connections */
  conn->bits.close = FALSE;

  if ( (conn->protocol&(PROT_HTTP|PROT_FTP)) &&
       data->set.upload) {
    data->set.httpreq = HTTPREQ_PUT;
  }

  request = data->set.customrequest?
    data->set.customrequest:
    (data->set.no_body?(char *)"HEAD":
     ((HTTPREQ_POST == data->set.httpreq) ||
      (HTTPREQ_POST_FORM == data->set.httpreq))?(char *)"POST":
     (HTTPREQ_PUT == data->set.httpreq)?(char *)"PUT":(char *)"GET");
  
  /* The User-Agent string has been built in url.c already, because it might
     have been used in the proxy connect, but if we have got a header with
     the user-agent string specified, we erase the previously made string
     here. */
  if(checkheaders(data, "User-Agent:") && conn->allocptr.uagent) {
    free(conn->allocptr.uagent);
    conn->allocptr.uagent=NULL;
  }

  /* setup the authentication headers */
  result = http_auth_headers(conn, request, ppath, &authdone);
  if(result)
    return result;

  Curl_safefree(conn->allocptr.ref);
  if(data->change.referer && !checkheaders(data, "Referer:"))
    conn->allocptr.ref = aprintf("Referer: %s\015\012", data->change.referer);
  else
    conn->allocptr.ref = NULL;

  Curl_safefree(conn->allocptr.cookie);
  if(data->set.cookie && !checkheaders(data, "Cookie:"))
    conn->allocptr.cookie = aprintf("Cookie: %s\015\012", data->set.cookie);
  else
    conn->allocptr.cookie = NULL;

  if(!conn->bits.upload_chunky && (data->set.httpreq != HTTPREQ_GET)) {
    /* not a chunky transfer but data is to be sent */
    ptr = checkheaders(data, "Transfer-Encoding:");
    if(ptr) {
      /* Some kind of TE is requested, check if 'chunked' is chosen */
      if(Curl_compareheader(ptr, "Transfer-Encoding:", "chunked"))
        /* we have been told explicitly to upload chunky so deal with it! */
        conn->bits.upload_chunky = TRUE;
    }
  }

  if(conn->bits.upload_chunky) {
    /* RFC2616 section 4.4:
       Messages MUST NOT include both a Content-Length header field and a
       non-identity transfer-coding. If the message does include a non-
       identity transfer-coding, the Content-Length MUST be ignored. */

    if(!checkheaders(data, "Transfer-Encoding:")) {
      te = "Transfer-Encoding: chunked\r\n";
    }
    else {
      /* The "Transfer-Encoding:" header was already added. */
      te = "";
    }
  }

  ptr = checkheaders(data, "Host:");
  if(ptr) {
    /* If we have a given custom Host: header, we extract the host name
       in order to possibly use it for cookie reasons later on. */
    char *start = ptr+strlen("Host:");
    while(*start && isspace((int)*start ))
      start++;
    ptr = start; /* start host-scanning here */

    /* scan through the string to find the end (space or colon) */
    while(*ptr && !isspace((int)*ptr) && !(':'==*ptr))
      ptr++;
    
    if(ptr != start) {
      int len=ptr-start;
      conn->allocptr.cookiehost = malloc(len+1);
      if(!conn->allocptr.cookiehost)
        return CURLE_OUT_OF_MEMORY;
      memcpy(conn->allocptr.cookiehost, start, len);
      conn->allocptr.cookiehost[len]=0;
    }
  }    
  else {
    /* if ptr_host is already set, it is almost OK since we only re-use
       connections to the very same host and port, but when we use a HTTP
       proxy we have a persistant connect and yet we must change the Host:
       header! */

    if(conn->allocptr.host)
      free(conn->allocptr.host);

    /* When building Host: headers, we must put the host name within
       [brackets] if the host name is a plain IPv6-address. RFC2732-style. */
       
    if(((conn->protocol&PROT_HTTPS) && (conn->remote_port == PORT_HTTPS)) ||
       (!(conn->protocol&PROT_HTTPS) && (conn->remote_port == PORT_HTTP)) )
      /* If (HTTPS on port 443) OR (non-HTTPS on port 80) then don't include
         the port number in the host string */
      conn->allocptr.host = aprintf("Host: %s%s%s\r\n",
                                    conn->bits.ipv6_ip?"[":"",
                                    host,
                                    conn->bits.ipv6_ip?"]":"");
    else
      conn->allocptr.host = aprintf("Host: %s%s%s:%d\r\n",
                                    conn->bits.ipv6_ip?"[":"",
                                    host,
                                    conn->bits.ipv6_ip?"]":"",
                                    conn->remote_port);

    if(!conn->allocptr.host)
      /* without Host: we can't make a nice request */
      return CURLE_OUT_OF_MEMORY;
  }

  if(data->cookies) {
    Curl_share_lock(data, CURL_LOCK_DATA_COOKIE, CURL_LOCK_ACCESS_SINGLE);
    co = Curl_cookie_getlist(data->cookies,
                             conn->allocptr.cookiehost?
                             conn->allocptr.cookiehost:host, ppath,
                             (bool)(conn->protocol&PROT_HTTPS?TRUE:FALSE));
    Curl_share_unlock(data, CURL_LOCK_DATA_COOKIE);
  }

  if (conn->bits.httpproxy &&
      !data->set.tunnel_thru_httpproxy &&
      !(conn->protocol&PROT_HTTPS))  {
    /* The path sent to the proxy is in fact the entire URL */
    ppath = data->change.url;
  }
  if(HTTPREQ_POST_FORM == data->set.httpreq) {
    /* we must build the whole darned post sequence first, so that we have
       a size of the whole shebang before we start to send it */
     result = Curl_getFormData(&http->sendit, data->set.httppost,
                               &http->postsize);
     if(CURLE_OK != result) {
       /* Curl_getFormData() doesn't use failf() */
       failf(data, "failed creating formpost data");
       return result;
     }
  }


  if(!checkheaders(data, "Pragma:"))
    http->p_pragma = "Pragma: no-cache\r\n";

  if(!checkheaders(data, "Accept:"))
    http->p_accept = "Accept: image/gif, image/x-xbitmap, image/jpeg, image/pjpeg, */*\r\n";

  if(( (HTTPREQ_POST == data->set.httpreq) ||
       (HTTPREQ_POST_FORM == data->set.httpreq) ||
       (HTTPREQ_PUT == data->set.httpreq) ) &&
     conn->resume_from) {
    /**********************************************************************
     * Resuming upload in HTTP means that we PUT or POST and that we have
     * got a resume_from value set. The resume value has already created
     * a Range: header that will be passed along. We need to "fast forward"
     * the file the given number of bytes and decrease the assume upload
     * file size before we continue this venture in the dark lands of HTTP.
     *********************************************************************/
   
    if(conn->resume_from < 0 ) {
      /*
       * This is meant to get the size of the present remote-file by itself.
       * We don't support this now. Bail out!
       */
       conn->resume_from = 0;
    }

    if(conn->resume_from) {
      /* do we still game? */
      int passed=0;

      /* Now, let's read off the proper amount of bytes from the
         input. If we knew it was a proper file we could've just
         fseek()ed but we only have a stream here */
      do {
        int readthisamountnow = (conn->resume_from - passed);
        int actuallyread;

        if(readthisamountnow > BUFSIZE)
          readthisamountnow = BUFSIZE;

        actuallyread =
          data->set.fread(data->state.buffer, 1, readthisamountnow,
                          data->set.in);

        passed += actuallyread;
        if(actuallyread != readthisamountnow) {
          failf(data, "Could only read %d bytes from the input",
                passed);
          return CURLE_READ_ERROR;
        }
      } while(passed != conn->resume_from); /* loop until done */

      /* now, decrease the size of the read */
      if(data->set.infilesize>0) {
        data->set.infilesize -= conn->resume_from;

        if(data->set.infilesize <= 0) {
          failf(data, "File already completely uploaded");
          return CURLE_PARTIAL_FILE;
        }
      }
      /* we've passed, proceed as normal */
    }
  }
  if(conn->bits.use_range) {
    /*
     * A range is selected. We use different headers whether we're downloading
     * or uploading and we always let customized headers override our internal
     * ones if any such are specified.
     */
    if((data->set.httpreq == HTTPREQ_GET) &&
       !checkheaders(data, "Range:")) {
      /* if a line like this was already allocated, free the previous one */
      if(conn->allocptr.rangeline)
        free(conn->allocptr.rangeline);
      conn->allocptr.rangeline = aprintf("Range: bytes=%s\r\n", conn->range);
    }
    else if((data->set.httpreq != HTTPREQ_GET) &&
            !checkheaders(data, "Content-Range:")) {

      if(conn->resume_from) {
        /* This is because "resume" was selected */
        long total_expected_size= conn->resume_from + data->set.infilesize;
        conn->allocptr.rangeline = aprintf("Content-Range: bytes %s%ld/%ld\r\n",
                                      conn->range, total_expected_size-1,
                                      total_expected_size);
      }
      else {
        /* Range was selected and then we just pass the incoming range and 
           append total size */
        conn->allocptr.rangeline = aprintf("Content-Range: bytes %s/%d\r\n",
                                      conn->range, data->set.infilesize);
      }
    }
  }

  {
    /* Use 1.1 unless the use specificly asked for 1.0 */
    const char *httpstring=
      data->set.httpversion==CURL_HTTP_VERSION_1_0?"1.0":"1.1";

    send_buffer *req_buffer;
    struct curl_slist *headers=data->set.headers;
    size_t postsize;

    /* initialize a dynamic send-buffer */
    req_buffer = add_buffer_init();

    if(!req_buffer)
      return CURLE_OUT_OF_MEMORY;

    /* add the main request stuff */
    result =
      add_bufferf(req_buffer,
                  "%s " /* GET/HEAD/POST/PUT */
                  "%s HTTP/%s\r\n" /* path + HTTP version */
                  "%s" /* proxyuserpwd */
                  "%s" /* userpwd */
                  "%s" /* range */
                  "%s" /* user agent */
                  "%s" /* cookie */
                  "%s" /* host */
                  "%s" /* pragma */
                  "%s" /* accept */
                  "%s" /* accept-encoding */
                  "%s" /* referer */
                  "%s",/* transfer-encoding */

                request,
                ppath,
                httpstring,
                (conn->bits.httpproxy && conn->allocptr.proxyuserpwd)?
                conn->allocptr.proxyuserpwd:"",
                conn->allocptr.userpwd?conn->allocptr.userpwd:"",
                (conn->bits.use_range && conn->allocptr.rangeline)?
                conn->allocptr.rangeline:"",
                (data->set.useragent && *data->set.useragent && conn->allocptr.uagent)?
                conn->allocptr.uagent:"",
                (conn->allocptr.cookie?conn->allocptr.cookie:""), /* Cookie: <data> */
                (conn->allocptr.host?conn->allocptr.host:""), /* Host: host */
                http->p_pragma?http->p_pragma:"",
                http->p_accept?http->p_accept:"",
                (data->set.encoding && *data->set.encoding && conn->allocptr.accept_encoding)?
                conn->allocptr.accept_encoding:"", /* 08/28/02 jhrg */
                (data->change.referer && conn->allocptr.ref)?conn->allocptr.ref:"" /* Referer: <data> <CRLF> */,
                te
                );

    if(result)
      return result;

    if(co) {
      int count=0;
      struct Cookie *store=co;
      /* now loop through all cookies that matched */
      while(co) {
        if(co->value) {
          if(0 == count) {
            add_bufferf(req_buffer, "Cookie: ");
          }
          add_bufferf(req_buffer,
                      "%s%s=%s", count?"; ":"", co->name, co->value);
          count++;
        }
        co = co->next; /* next cookie please */
      }
      if(count) {
        add_buffer(req_buffer, "\r\n", 2);
      }
      Curl_cookie_freelist(store); /* free the cookie list */
      co=NULL;
    }

    if(data->set.timecondition) {
      struct tm *thistime;

      /* Phil Karn (Fri, 13 Apr 2001) pointed out that the If-Modified-Since
       * header family should have their times set in GMT as RFC2616 defines:
       * "All HTTP date/time stamps MUST be represented in Greenwich Mean Time
       * (GMT), without exception. For the purposes of HTTP, GMT is exactly
       * equal to UTC (Coordinated Universal Time)." (see page 20 of RFC2616).
       */

#ifdef HAVE_GMTIME_R
      /* thread-safe version */
      struct tm keeptime;
      thistime = (struct tm *)gmtime_r(&data->set.timevalue, &keeptime);
#else
      thistime = gmtime(&data->set.timevalue);
#endif

#ifdef HAVE_STRFTIME
      /* format: "Tue, 15 Nov 1994 12:45:26 GMT" */
      strftime(buf, BUFSIZE-1, "%a, %d %b %Y %H:%M:%S GMT", thistime);
#else
      /* TODO: Right, we *could* write a replacement here */
      strcpy(buf, "no strftime() support");
#endif
      switch(data->set.timecondition) {
      case CURL_TIMECOND_IFMODSINCE:
      default:
        add_bufferf(req_buffer,
                    "If-Modified-Since: %s\r\n", buf);
        break;
      case CURL_TIMECOND_IFUNMODSINCE:
        add_bufferf(req_buffer,
                    "If-Unmodified-Since: %s\r\n", buf);
        break;
      case CURL_TIMECOND_LASTMOD:
        add_bufferf(req_buffer,
                    "Last-Modified: %s\r\n", buf);
        break;
      }
    }

    while(headers) {
      ptr = strchr(headers->data, ':');
      if(ptr) {
        /* we require a colon for this to be a true header */

        ptr++; /* pass the colon */
        while(*ptr && isspace((int)*ptr))
          ptr++;

        if(*ptr) {
          /* only send this if the contents was non-blank */

          add_bufferf(req_buffer, "%s\r\n", headers->data);
        }
      }
      headers = headers->next;
    }

    http->postdata = NULL;  /* nothing to post at this point */
    Curl_pgrsSetUploadSize(data, 0); /* upload size is 0 atm */

    if(!authdone)
      /* until the auth is done, pretend we only do GET */
      httpreq = HTTPREQ_GET;
    else
      httpreq = data->set.httpreq;

    switch(httpreq) {

    case HTTPREQ_POST_FORM:
      if(Curl_FormInit(&http->form, http->sendit)) {
        failf(data, "Internal HTTP POST error!");
        return CURLE_HTTP_POST_ERROR;
      }

      /* set the read function to read from the generated form data */
      conn->fread = (curl_read_callback)Curl_FormReader;
      conn->fread_in = &http->form;

      http->sending = HTTPSEND_BODY;

      if(!conn->bits.upload_chunky)
        /* only add Content-Length if not uploading chunked */
        add_bufferf(req_buffer,
                    "Content-Length: %d\r\n", http->postsize);

      if(!checkheaders(data, "Expect:")) {
        /* if not disabled explicitly we add a Expect: 100-continue
           to the headers which actually speeds up post operations (as
           there is one packet coming back from the web server) */
        add_bufferf(req_buffer,
                    "Expect: 100-continue\r\n");
        data->set.expect100header = TRUE;
      }

      if(!checkheaders(data, "Content-Type:")) {
        /* Get Content-Type: line from Curl_FormReadOneLine, which happens
           to always be the first line. We can know this for sure since
           we always build the formpost linked list the same way!

           The Content-Type header line also contains the MIME boundary
           string etc why disabling this header is likely to not make things
           work, but we support it anyway.
        */
        char contentType[256];
        int linelength=0;
        linelength = Curl_FormReadOneLine (contentType,
                                           sizeof(contentType),
                                           1,
                                           (FILE *)&http->form);
        if(linelength == -1) {
          failf(data, "Could not get Content-Type header line!");
          return CURLE_HTTP_POST_ERROR;
        }
        add_buffer(req_buffer, contentType, linelength);
      }

      /* make the request end in a true CRLF */
      add_buffer(req_buffer, "\r\n", 2);

      /* set upload size to the progress meter */
      Curl_pgrsSetUploadSize(data, http->postsize);

      /* fire away the whole request to the server */
      result = add_buffer_send(req_buffer, conn, 
                               &data->info.request_size);
      if(result)
        failf(data, "Failed sending POST request");
      else
        /* setup variables for the upcoming transfer */
        result = Curl_Transfer(conn, FIRSTSOCKET, -1, TRUE,
                               &http->readbytecount,
                               FIRSTSOCKET,
                               &http->writebytecount);
      if(result) {
        Curl_formclean(http->sendit); /* free that whole lot */
        return result;
      }
      break;

    case HTTPREQ_PUT: /* Let's PUT the data to the server! */

      if((data->set.infilesize>0) && !conn->bits.upload_chunky)
        /* only add Content-Length if not uploading chunked */
        add_bufferf(req_buffer,
                    "Content-Length: %d\r\n", /* file size */
                    data->set.infilesize );

      add_bufferf(req_buffer, "\r\n");

      /* set the upload size to the progress meter */
      Curl_pgrsSetUploadSize(data, data->set.infilesize);

      /* this sends the buffer and frees all the buffer resources */
      result = add_buffer_send(req_buffer, conn,
                               &data->info.request_size);
      if(result)
        failf(data, "Failed sending POST request");
      else
        /* prepare for transfer */
        result = Curl_Transfer(conn, FIRSTSOCKET, -1, TRUE,
                               &http->readbytecount,
                               FIRSTSOCKET,
                               &http->writebytecount);
      if(result)
        return result;
      break;

    case HTTPREQ_POST:
      /* this is the simple POST, using x-www-form-urlencoded style */

      /* store the size of the postfields */
      postsize = data->set.postfieldsize?
        data->set.postfieldsize:
        (data->set.postfields?strlen(data->set.postfields):0);
      
      if(!conn->bits.upload_chunky) {
        /* We only set Content-Length and allow a custom Content-Length if
           we don't upload data chunked, as RFC2616 forbids us to set both
           kinds of headers (Transfer-Encoding: chunked and Content-Length) */

        if(!checkheaders(data, "Content-Length:"))
          /* we allow replacing this header, although it isn't very wise to
             actually set your own */
          add_bufferf(req_buffer, "Content-Length: %d\r\n", postsize);
      }

      if(!checkheaders(data, "Content-Type:"))
        add_bufferf(req_buffer,
                    "Content-Type: application/x-www-form-urlencoded\r\n");

      add_buffer(req_buffer, "\r\n", 2);

      if(data->set.postfields) {

        if(postsize < (100*1024)) {
          /* The post data is less than 100K, then append it to the header.
             This limit is no magic limit but only set to prevent really huge
             POSTs to get the data duplicated with malloc() and family. */

          if(!conn->bits.upload_chunky)
            /* We're not sending it 'chunked', append it to the request
               already now to reduce the number if send() calls */
            add_buffer(req_buffer, data->set.postfields, postsize);
          else {
            /* Append the POST data chunky-style */
            add_bufferf(req_buffer, "%x\r\n", postsize);
            add_buffer(req_buffer, data->set.postfields, postsize);
            add_buffer(req_buffer, "\r\n0\r\n", 5); /* end of a chunked
                                                       transfer stream */
          }
        }
        else {
          /* A huge POST coming up, do data separate from the request */
          http->postsize = postsize;
          http->postdata = data->set.postfields;

          http->sending = HTTPSEND_BODY;

          conn->fread = (curl_read_callback)readmoredata;
          conn->fread_in = (void *)conn;

          /* set the upload size to the progress meter */
          Curl_pgrsSetUploadSize(data, http->postsize);
        }
      }
      else {
        /* set the upload size to the progress meter */
        Curl_pgrsSetUploadSize(data, data->set.infilesize);

        /* set the pointer to mark that we will send the post body using
           the read callback */
        http->postdata = (char *)&http->postdata;
      }
      /* issue the request */
      result = add_buffer_send(req_buffer, conn,
                               &data->info.request_size);

      if(result)
        failf(data, "Failed sending HTTP POST request");
      else
        result =
          Curl_Transfer(conn, FIRSTSOCKET, -1, TRUE,
                        &http->readbytecount,
                        http->postdata?FIRSTSOCKET:-1,
                        http->postdata?&http->writebytecount:NULL);
      break;

    default:
      add_buffer(req_buffer, "\r\n", 2);
      
      /* issue the request */
      result = add_buffer_send(req_buffer, conn,
                               &data->info.request_size);

      if(result)
        failf(data, "Failed sending HTTP request");
      else
        /* HTTP GET/HEAD download: */
        result = Curl_Transfer(conn, FIRSTSOCKET, -1, TRUE,
                               &http->readbytecount,
                               http->postdata?FIRSTSOCKET:-1,
                               http->postdata?&http->writebytecount:NULL);
    }
    if(result)
      return result;
  }

  return CURLE_OK;
}
#endif