使用libcurl POST数据和上传文件

一时失言乱红尘 2022-08-05 00:34 267阅读 0赞

*  为了具有通用性，将文件的内容读到了fc变量中，fclen是fc的长度。fc也可以是任何其它内容。curl 是 libcurl句柄。演示省略了很多显而易见的步骤。
    
      
    
    
    1. 普通的post请求，这里用curl\_easy\_escape对fc做了编码
    
    std::string data("req=plain");
    
    data.append("&file=");
    
    char \*efc = curl\_easy\_escape(curl, fc, fclen);
    
    data.append(efc)
    
    curl\_free(encoded);
    
      
    
    
    curl\_easy\_setopt(curl, CURLOPT\_URL, PURGE\_URL);
    
    curl\_easy\_setopt(curl, CURLOPT\_POST, 1L);
    
    curl\_easy\_setopt(curl, CURLOPT\_POSTFIELDS, data.c\_str());
    
    curl\_easy\_setopt(curl, CURLOPT\_POSTFIELDSIZE, data.size());
    
      
    
    
    2. multipart/formdata请求
    
    struct curl\_httppost \*formpost = 0;
    
    struct curl\_httppost \*lastptr  = 0;
    
    curl\_formadd(&formpost, &lastptr, CURLFORM\_PTRNAME, "reqformat", CURLFORM\_PTRCONTENTS, "plain", CURLFORM\_END);
    
    curl\_formadd(&formpost, &lastptr, CURLFORM\_PTRNAME, "file", CURLFORM\_PTRCONTENTS, fc, CURLFORM\_CONTENTSLENGTH, fclen, CURLFORM\_END);
    
      
    
    
    curl\_easy\_setopt(curl, CURLOPT\_URL, URL);
    
    curl\_easy\_setopt(curl, CURLOPT\_HTTPPOST, formpost);
    
    curl\_easy\_perform(curl);
    
    curl\_formfree(formpost);
    
      
    
    
    3. multipart/formdata请求，不把文件读入fc，其它步骤相同
    
    curl\_formadd(&formpost, &lastptr, CURLFORM\_PTRNAME, "file", CURLFORM\_FILE, "/path/filename", CURLFORM\_END);
    
      
    
    
    4. 通过put上传文件
    
    curl\_easy\_setopt(curl, CURLOPT\_UPLOAD, 1L);
    
    curl\_easy\_setopt(curl, CURLOPT\_PUT, 1L);
    
    curl\_easy\_setopt(curl, CURLOPT\_READDATA, fp);   // FILE \*fp = fopen("/path/filename");
    
    curl\_easy\_setopt(curl, CURLOPT\_INFILESIZE\_LARGE, fsize);  // fsize = sizeof /path/filename
    
      
    
    
    5. 发送自己的Header
    
    struct curl\_slist \*slist = 0;
    
    slist = curl\_slist\_append(slist, "Blog-X-User: username");
    
    slist = curl\_slist\_append(slist, "Blog-X-Signature: signature");
    
    curl\_easy\_setopt(curl, CURLOPT\_HTTPHEADER, slist);
    
    curl\_slist\_free\_all(slist);