使用CURL上传文件curl_formadd的一个例子

 /*****************************************************************************
 *                                  _   _ ____  _    
 *  Project                     ___| | | |  _ /| |   
 *                             / __| | | | |_) | |   
 *                            | (__| |_| |  _ <| |___
 *                             /___|/___/|_| /_/_____|
 *
 * $Id: multi-post.c,v 1.1 2002/05/06 13:38:28 bagder Exp $
 *
 * This is an example application source code using the multi interface
 * to do a multipart formpost without "blocking".
 */
#include <stdio.h>
#include <string.h>
#include <time.h>
#include <winsock2.h>

#include "curl.h"

#define TOHEX(x) ((x)>9 ? (x)+55 : (x)+48)
void URLEncode(char* szIn, char** pOut);

int main(int argc, char *argv[])
{
  CURL *curl;
//  CURLcode res;

  CURLM *multi_handle;
  int still_running;

  struct HttpPost *formpost=NULL;
  struct HttpPost *lastptr=NULL;
  struct curl_slist *headerlist=NULL;
  char buf[] = "Expect:";

  char name[] = "进步.txt";
  char* pUrlName = NULL;
  URLEncode(name, &pUrlName);

  curl_formadd((curl_httppost**)&formpost,
               (curl_httppost**)&lastptr,
               CURLFORM_COPYNAME, "__VIEWSTATE",
               CURLFORM_COPYCONTENTS, "dDw4ODE3NDk3ODk7Oz7wjZQSjAs1UJPOWebtakpkNfcu/w==",//old
//               CURLFORM_COPYCONTENTS, "dDw4ODE3NDk3ODk7Oz5EO36hoeY0AjmXXbTuRliuM0KJ3w==",//new
//               CURLFORM_COPYCONTENTS, "dDw4ODE3NDk3ODk7Oz7PeymyMHBp1qNYBrSPBdI2MqFLRw==",//new
               CURLFORM_END);

  /* Fill in the file upload field */
  curl_formadd((curl_httppost**)&formpost,
               (curl_httppost**)&lastptr,
               CURLFORM_COPYNAME, "File1",
               CURLFORM_FILE, "d://进步.txt",
               CURLFORM_FILENAME, pUrlName,
               CURLFORM_END);

/*  curl_formadd((curl_httppost**)&formpost,
               (curl_httppost**)&lastptr,
               CURLFORM_COPYNAME, "filename",
               CURLFORM_FILENAME, "tt.bmp",
               CURLFORM_END);
*/
  /* Fill in the filename field */
  curl_formadd((curl_httppost**)&formpost,
               (curl_httppost**)&lastptr,
               CURLFORM_COPYNAME, "filename",
               CURLFORM_COPYCONTENTS, "tt.bmp",
               CURLFORM_END);

  /* Fill in the submit field too, even if this is rarely needed */
  curl_formadd((curl_httppost**)&formpost,
               (curl_httppost**)&lastptr,
               CURLFORM_COPYNAME, "CmdUpload",
               CURLFORM_COPYCONTENTS, "UpLoad",
               CURLFORM_END);

  curl = curl_easy_init();
  multi_handle = curl_multi_init();

  /* initalize custom header list (stating that Expect: 100-continue is not
     wanted */
  headerlist = curl_slist_append(headerlist, buf);
  if(curl && multi_handle) {
    int perform=0;

    /* what URL that receives this POST */
    curl_easy_setopt(curl, CURLOPT_URL,
                     "http://192.168.160.99/FileUploadDemo.aspx");

    curl_easy_setopt(curl, CURLOPT_VERBOSE, 1);

    curl_easy_setopt(curl, CURLOPT_HTTPHEADER, headerlist);
    curl_easy_setopt(curl, CURLOPT_HTTPPOST, formpost);

    curl_multi_add_handle(multi_handle, curl);

    while(CURLM_CALL_MULTI_PERFORM ==
          curl_multi_perform(multi_handle, &still_running));

    while(still_running) {
      struct timeval timeout;
      int rc; /* select() return code */

      fd_set fdread;
      fd_set fdwrite;
      fd_set fdexcep;
      int maxfd;

      FD_ZERO(&fdread);
      FD_ZERO(&fdwrite);
      FD_ZERO(&fdexcep);

      /* set a suitable timeout to play around with */
      timeout.tv_sec = 1;
      timeout.tv_usec = 0;

      /* get file descriptors from the transfers */
      curl_multi_fdset(multi_handle, &fdread, &fdwrite, &fdexcep, &maxfd);

      rc = select(maxfd+1, &fdread, &fdwrite, &fdexcep, &timeout);

      switch(rc) {
      case -1:
        /* select error */
        break;
      case 0:
        printf("timeout!/n");
      default:
        /* timeout or readable/writable sockets */
        printf("perform!/n");
        while(CURLM_CALL_MULTI_PERFORM ==
              curl_multi_perform(multi_handle, &still_running));
        printf("running: %d!/n", still_running);
        break;
   }
    }

    curl_multi_cleanup(multi_handle);

    /* always cleanup */
    curl_easy_cleanup(curl);

    /* then cleanup the formpost chain */
    curl_formfree((curl_httppost*)formpost);

    /* free slist */
    curl_slist_free_all (headerlist);
  }
  delete[] pUrlName;
  return 0;
}

void URLEncode(char* szIn, char** pOut)
{
 int nInLenth = strlen(szIn);
 int nFlag = 0;
 BYTE byte;
 *pOut = new char[nInLenth*3];
 char* szOut = *pOut;
 for (int i=0; i<nInLenth; i++)
 {
  byte = szIn[i];
  if (isalnum(byte))
  {
   szOut[nFlag++] = byte;
  }
  else
  {
   if (isspace(byte))
   {
    szOut[nFlag++] = '+';
   }
   else
   {
    szOut[nFlag++] = '%';
    szOut[nFlag++] = TOHEX(byte>>4);
    szOut[nFlag++] = TOHEX(byte%16);
   }
  }
 }
 szOut[nFlag] = '/0';
}


相关的html代码如下：

<%@Page Language="C#"%>
<HTML>
 <HEAD>
  <TITLE>
   File Uploading in ASP.Net Using C# - Demo
  </TITLE>
 </HEAD>
<BODY>
<script language="C#" runat="Server">
 //Event Handler for the upload button
 void UploadFile(object Sender,EventArgs E)
 {
  if (File1.PostedFile !=null) //Checking for valid file
  {  
   // Since the PostedFile.FileNameFileName gives the entire path we use Substring function to rip of the filename alone.
   string StrFileName = File1.PostedFile.FileName.Substring(File1.PostedFile.FileName.LastIndexOf("//") + 1) ;
   string StrFileType = File1.PostedFile.ContentType ;
   int IntFileSize =File1.PostedFile.ContentLength;
   //Checking for the length of the file. If length is 0 then file is not uploaded.
   if (IntFileSize <=0)
    Response.Write(" <font color='Red' size='2'>Uploading of file " + StrFileName + " failed </font>");
   else
   {
    File1.PostedFile.SaveAs(Server.MapPath(".//" + StrFileName));
    Response.Write("<font color='green' size='2'>Your file " + StrFileName + " oftype " + StrFileType + " and size " + IntFileSize.ToString() + " byteswas uploaded successfully</font>");
   }
  }
 }
</script>
<%if(!Page.IsPostBack)
{
%>
<H2 align="center">File uploading in ASP.Net using C# - Demo</H2>
<!-- Declaration of server side form. Note the enctype attribute of the form has to be set to multipart/form-data -->
<form id="FrmFileUploadDemo" name="FrmFileUploadDemo"  method="post" enctype="multipart/form-data" runat="server" >
 <TABLE align="center" bgcolor="lightyellow">
  <TR>
   <TD>
    <font size="2">Select a file to upload</font> <input type="file" id="File1" name="File1" runat="server">
   </TD>
  <TR>
  <TR>
   <TD align="center">
    <asp:button value="Upload" runat="server" id="CmdUpload" Text="UpLoad" onClick="UploadFile" />
   </TD>
  </TR>
 </TABLE>
</form>
<%}%>

<BR><BR><BR><BR><BR><BR><BR><BR><BR><BR><BR><BR>
<font size="2">
Please feel to contact the author <a href="mailto:[e-mail]">Sriram</a> for
your valuable suggestions and feedbacks.</font>

</BODY>
</HTML>