libcurl第七課 multipart/formdata表單使用

場景
         multipart/form-data是瀏覽器用表單上傳文件的方式。最多見的情境是：在寫郵件時，向郵件後添加附件，附件一般使用表單添加，也就是用multipart/form-data格式上傳到服務器。Http服務器定義了上傳數據的格式，接口地址 http://10.10.10.10:80/restful/personInfo，參數以下：
msg:{
   "name" : "fengyuzaitu",
   "data" : {
      "id" : "9191"
   },
   "sex" : "1",
   "type" : "worker"
}

代碼
int PostHttpFormDataByLibCurl()
{
 Json::Value root;
 root["type"] = "worker";
 root["sex"] = "1";
 root["name"] = "fengyuzaitu";
 Json::Value data;
 data["id"] = "9191";
 root["data"] = data;
 std::string strPostData = root.toStyledString();
 CURL *pCurlHandle = curl_easy_init();
 std::string strResponseData;
 curl_easy_setopt(pCurlHandle, CURLOPT_CUSTOMREQUEST, "POST");
 curl_easy_setopt(pCurlHandle, CURLOPT_URL, "http://10.10.10.10:80/restful/personInfo");
 curl_easy_setopt(pCurlHandle, CURLOPT_WRITEFUNCTION, WriteResponseBody);//設置回調函數
 curl_easy_setopt(pCurlHandle, CURLOPT_WRITEDATA, &strResponseData);//設置回調函數的參數,獲取反饋信息
 struct curl_httppost *pFormPost = 0;
 struct curl_httppost *pLastPtrFormPost = 0;
 curl_formadd(&pFormPost, &pLastPtrFormPost, CURLFORM_COPYNAME, "msg", CURLFORM_COPYCONTENTS, strPostData.c_str(), CURLFORM_END);
 curl_easy_setopt(pCurlHandle, CURLOPT_HTTPPOST, pFormPost);
 CURLcode nRet = curl_easy_perform(pCurlHandle);
 if (0 == nRet)
 {
  std::cout << strResponseData << std::endl;
 }
 curl_formfree(pFormPost);
 curl_easy_cleanup(pCurlHandle);
 return nRet;
}

報文
POST /restful/personInfo HTTP/1.1
Host: 10.10.10.10:80
Accept: */*
Content-Length: 254
Expect: 100-continue
Content-Type: multipart/form-data; boundary=------------------------2630a8c6c773b062
HTTP/1.1 100
--------------------------2630a8c6c773b062
Content-Disposition: form-data; name="msg"
{
   "name" : "fengyuzaitu",
   "data" : {
      "id" : "9191"
   },
   "sex" : "1",
   "type" : "worker"
}
--------------------------2630a8c6c773b062--

備註
        這種表單上傳數據的方式，也能夠經過Content-Type: application/x-www-form-urlencoded的方式進行上傳
代碼
int PostFormDataByUrlEncode()
{
 Json::Value root;
 root["type"] = "worker";
 root["sex"] = "1";
 root["name"] = "fengyuzaitu";
 Json::Value data;
 data["id"] = "9191";
 root["data"] = data;
 std::string strUrl = root.toStyledString();
 CURL *pCurlHandle = curl_easy_init();
 std::string strResponseData;
 curl_easy_setopt(pCurlHandle, CURLOPT_CUSTOMREQUEST, "POST");
 curl_easy_setopt(pCurlHandle, CURLOPT_URL, "http://10.10.10.10:80/restful/personInfo");
 struct curl_slist *pCurlList = NULL;
 //指定文本url編碼
 pCurlList = curl_slist_append(pCurlList, "Content-Type: application/x-www-form-urlencoded");
 curl_easy_setopt(pCurlHandle, CURLOPT_HTTPHEADER, headers);
 curl_easy_setopt(pCurlHandle, CURLOPT_WRITEFUNCTION, WriteResponseBody);//設置回調函數
 curl_easy_setopt(pCurlHandle, CURLOPT_WRITEDATA, &strResponseData);//設置回調函數的參數,獲取反饋信息
 char* pszEncodeAuth = curl_easy_escape(pCurlHandle, strUrl.c_str(), strUrl.length());
 std::string strEncodeAuth = pszEncodeAuth;
 //釋放申請的內存
 curl_free(pszEncodeAuth);
 std::string strPostUrlEncodeData = "msg=" + strEncodeAuth;
 curl_easy_setopt(pCurlHandle, CURLOPT_POSTFIELDS, strPostUrlEncodeData.c_str());
 CURLcode nRet = curl_easy_perform(pCurlHandle);
 std::cout << strResponseData << std::endl;
 curl_slist_free_all(pCurlList);
 curl_easy_cleanup(pCurlHandle);
 return nRet;
}

注意：
 std::string strPostUrlEncodeData = "msg=" + strEncodeAuth; 這裏的=不能使用：,不然沒法解析經過