C++、JsonCpp、libcurl 和 UTF-8 问题

Question

我在使用 libcurl 与 C++ JsonCpp 库一起工作时遇到了一些问题，经过大量研究，我想出了这段代码：

int post(const string& call, const string& key, const string& value) {
  // (...)

  char* char_data=NULL; 
  struct curl_slist *headers=NULL;

  headers = curl_slist_append(headers, "Content-Type: application/json; charset=UTF-8");

  Json::Value root;
  root[key] = value;

  Json::StyledWriter writer;
  string data = writer.write(root);

  char_data = (char*) malloc((strlen(data.c_str())+1) * sizeof(char));
  strcpy(char_data, data.c_str());

  curl_easy_setopt(curl, CURLOPT_HTTPHEADER, headers); 
  curl_easy_setopt(curl, CURLOPT_POSTFIELDS, char_data);
  curl_easy_setopt(curl, CURLOPT_POSTFIELDSIZE, (long)strlen(char_data));

  // (...)
}

只要 data (C++ std:: string 保存 JSON 字符串表示形式）没有任何非 ASCII 字符。当它发生时，我从后端收到一个错误（用 Rails 3 编写）：

Started POST "/deployments/4c904f607d7c4249cf00002c/log.json" for 67.23.79.89 at Wed Sep 15 00:45:40 -0400 2010
  Processing by DeploymentsController#log as JSON
  Parameters: {"log"=>"0 upgraded, 0 newly \214\211K########talled, 0 to remove and 46 not upgraded.\n", "id"=>"4c904f607d7c4249cf00002c"}
Completed   in 6ms

BSON::InvalidStringEncoding (String not valid UTF-8):
  app/models/deployment.rb:161:in `log'
  app/models/deployment.rb:160:in `each'
  app/models/deployment.rb:160:in `log'
  app/controllers/deployments_controller.rb:54:in `log'

What is the best way to take a C++ sstring (in this case data), and secure it conversion it UTF-8, and then to a *char 变量可以与 libcurl 配合使用吗？

Answer 1

我发现了问题。它不在代码的那部分。我实际上是在进行字符串拆分，导致了问题。