promise-cpp应用--02与REST SDK配合应用

参考：C++ REST SDK中的异步任务库PPLX

--------------------------

#include <iostream>
#include <future>
#include <string>
#include <sstream>
#include <stdexcept>
#include <functional>
#include <locale>
#include <codecvt>
//
#include "pplx/pplxtasks.h" // #include <ppltasks.h>
#include "cpprest/uri.h"
#include "cpprest/uri_builder.h"
#include "cpprest/http_client.h"
#include "cpprest/json.h"

//
#ifndef  PROMISE_HEADONLY
  #define  PROMISE_HEADONLY
#endif
#include "promise-cpp/promise.hpp"

-----------------------

//--------------------------------------------------------------------------------------------
static std::map<std::string, std::string> &headers2map(web::http::http_headers &headers)
{
  std::map<std::string, std::string> map;
  for (auto &header : headers)
  {
    // utility::conversions::to_string_t(header.first);
    map.emplace(utility::conversions::to_utf8string(header.first), utility::conversions::to_utf8string(header.second));
  }
  return std::move(map);
}

-----------------------

//--------------------------------------------------------------------------------------------
promise::Promise &loadWithXhr(std::string &url, std::string &responseType, std::string &method, std::string &data, const std::multimap<std::string, std::string> &headers, promise::Defer &deferred)
{
  // web::json::value &headersJson = multimap2json(headers);
  std::transform(method.begin(), method.end(), method.begin(), towupper); // towupper  towlower
  web::http::method methodPara = utility::conversions::to_string_t(method);
  //
  web::uri uri(utility::conversions::to_string_t(url));
  web::http::client::http_client client(uri);
  //
  web::http::http_request request;
  request.set_method(methodPara);
  request.set_request_uri(L"");
  web::http::http_headers &req_headers = request.headers();
  // request.headers().add(web::http::header_names::accept, L"application/json");
  for (auto &item : headers)
  {
    req_headers.add(utility::conversions::to_string_t(item.first), utility::conversions::to_string_t(item.second));
  }
  if (methodPara != web::http::methods::GET && methodPara != web::http::methods::HEAD)
  {
    if (data != "")
    {
      // web::json::value jvalue = web::json::value::string(utility::conversions::to_string_t(data));
      // request.set_body(jvalue);    //responseTask = client.request(methodPara, L"", jvalue);
      request.set_body(utility::conversions::to_string_t(data));
    }
  }
  // pplx::task<web::http::http_response> responseTask = client.request(request); // client.request(methodPara);
  client.request(request)
      .then([=](web::http::http_response &response)
            {
              web::http::status_code status = response.status_code();
              std::map<std::string, std::string> &headers = headers2map(response.headers());
              std::string browserResponseType = utility::conversions::to_utf8string(response.headers().content_type());
              //
              if ((status < 200 || status >= 300)) //  && !(localFile && xhr.status == 0)
              {
                std::exception ex("request error!!!");
                deferred.reject(ex);
                return;
              }
              std::string &value = response.extract_utf8string(true).get();
              // std::cout << value << std::endl;
              deferred.resolve(headers, value);
              //
            });
  return deferred.getPromise();
}

-----------------------

//--------------------------------------------------------------------------------------------
static promise::Promise HttpRequestPromise()
{
  std::string url = "https://learn.microsoft.com/zh-cn/previous-versions/jj950083(v=vs.120)"s;
  url = "https://www.cnblogs.com/gispathfinder/ajax/TopLists.aspx"s;
  url = "https://www.cnblogs.com/gispathfinder/ajax/TopLists-error.aspx"s;
  std::string responseType = ""s;
  std::string method = "GET"s;
  std::string data = ""s;
  std::multimap<std::string, std::string> headers{};

  //
  return promise::newPromise([&](promise::Defer &deferred)
                             {
                               loadWithXhr(url, responseType, method, data, headers, deferred);
                               //
                             })
      .then([](std::map<std::string, std::string> &headers, std::string &responseStr) //
            {                                                                         //
              std::cout << responseStr << std::endl;
            })
      .fail([](std::exception &ex) { //
        std::cout << "exception: " << ex.what() << std::endl;
      });

  // .then([](std::map<std::string, std::string> &headers, std::string &responseStr) //
  //       {                            //
  //         std::cout << responseStr << std::endl;
  //       },                        //
  //       [](std::exception &ex) { //
  //         std::cout << ex.what() << std::endl;
  //       });
}

-----------------------

//--------------------------------------------------------------------------------------------
void PromiseCommand::OnClick()
{
  //
  // requestDirectSDKAsync();
  // // HTTPStreamingAsync.wait();
  // testPromise();
  HttpRequestPromise();
}

-----------------------