Question

我尝试使用cURL库下载zip文件。这是我用来发出请求的代码：

const char* RestClient::user_agent = VERSION;
/** initialize authentication variable */
std::string RestClient::user_pass =  std::string();
/** Authentication Methods implementation */
void RestClient::clearAuth(){
  RestClient::user_pass.clear();}
void RestClient::setAuth(const std::string& user,const std::string& password){
  RestClient::user_pass.clear();
  RestClient::user_pass += user+":"+password;}

/** @brief HTTP GET method  @param url to query @return response struct */

RestClient::response RestClient::get(const std::string& url){
  RestClient::response ret = {};
  CURL *curl = NULL;
  CURLcode res = CURLE_OK;

  curl = curl_easy_init();
  if (curl) {
    /** set basic authentication if present*/
    if(RestClient::user_pass.length()>0){
      curl_easy_setopt(curl, CURLOPT_HTTPAUTH, CURLAUTH_BASIC);
      curl_easy_setopt(curl, CURLOPT_USERPWD,RestClient::user_pass.c_str());
  }
  curl_easy_setopt(curl, CURLOPT_USERAGENT, RestClient::user_agent);
  curl_easy_setopt(curl, CURLOPT_URL, url.c_str());
  curl_easy_setopt(curl, CURLOPT_WRITEFUNCTION, RestClient::write_callback);
  curl_easy_setopt(curl, CURLOPT_WRITEDATA, &ret);
  curl_easy_setopt(curl, CURLOPT_HEADERFUNCTION, RestClient::header_callback);
  curl_easy_setopt(curl, CURLOPT_HEADERDATA, &ret);
  res = curl_easy_perform(curl);
  if (res != CURLE_OK)
  {
    ret.body = "Failed to query.";
    ret.code = -1;
    return ret;
  }
  long http_code = 0;
  curl_easy_getinfo(curl, CURLINFO_RESPONSE_CODE, &http_code);
  ret.code = static_cast<int>(http_code);

  curl_easy_cleanup(curl);
  curl_global_cleanup();}
return ret;}

write_callback：

 size_t RestClient::write_callback(void *data, size_t size, size_t nmemb,void *userdata)
{ RestClient::response* r;
  r = reinterpret_cast<RestClient::response*>(userdata);
  r->body.append(reinterpret_cast<char*>(data), size*nmemb);
  return (size * nmemb);}

HTTP请求应该是：

http://yourserver.com/zip/<filename>.zip?downloadKind=<original|preview>&assetIds=<comma-separated asset ids>

当我发送请求时：

RestClient::response response = RestClient::get("http://localhost:8080/zip/tesst.zip?downloadKind=original&assetIds=60ZRK8LQ4RW8CYeZSzFmi0");

我得到＆＃34; 200＆＃34;作为响应代码和＆＃34; PK＆＃34;作为回应机构。什么＆＃34; PK＆＃34;意思？我做错了什么？

Answer 1

好的，问题有点缺乏细节，但我会猜测。

您的body成员变量属于std::string类型，不适合存储二进制数据。碰巧，ZIP文件通常以字节50 4b 03 04 xx 00开头，所以如果你把它解释为C字符串，那么它们将以00字节结束。

您可以使用std::vector<char>作为body的类型而不是std::string。这将正确处理二进制数据。

PS：从技术上讲，std::string可以处理嵌入的NUL字符，但我敢打赌。无论如何，这不是工作的正确工具。

为什么我会得到＆＃34; PK＆＃34;尝试下载zip文件时在HTTP响应中？

1 个答案: