C++ How to parse JSON response using cppRest Library? - c++

Question

I am trying to parse JSON response using cppRest Library, but an exception is raised instead the JSON object, here is the error that is show below:
Incorrect Content-Type: must be textual to extract_string, JSON to extract_json.
And here is my code that I have tried so far:
#include <iostream>
#include <cpprest/http_client.h>
using namespace web::http;
using namespace web::http::client;
using namespace web;
using namespace std;
int main()
{
uri url(L"http://www.7timer.info/bin/astro.php?lon=113.2&lat=23.1&ac=0&unit=metric&output=json&tzshift=0");
http_client client(url);
http_response response;
http_request req;
req.set_method(methods::GET);
req.headers().set_content_type(L"application/json");
response = client.request(req).get();
try
{
json::object json_object(response.extract_json().get().as_object());
}
catch (exception &e)
{
cout << e.what() << "\n";
}
return 0;
}

Answer 1

I solved my problem, looks like I need to set the response headers to get the received content type as json:
Updated my code:
#include <iostream>
#include <cpprest/http_client.h>
using namespace web::http;
using namespace web::http::client;
using namespace web;
using namespace std;
int main()
{
uri url(L"http://www.7timer.info/bin/astro.php?lon=113.2&lat=23.1&ac=0&unit=metric&output=json&tzshift=0");
http_client client(url);
http_request req;
req.set_method(methods::GET);
pplx::task<json::value> requestTask = client.request(req).then([](http_response response)
{
json::value jsonObject;
try
{
if ( response.status_code() == status_codes::OK )
{
response.headers().set_content_type(L"application/json"); // Set headers to receive content type as JSON
jsonObject = response.extract_json().get();
}
}
catch (const http_exception& e)
{
cout << e.error_code().message() << "\n";
}
return jsonObject; // returned a json value
});
json::array dataseries = requestTask.get().at(L"dataseries").as_array(); // We get the returned response here
for (size_t i = 0; i < dataseries.size(); i++)
{
auto timepoint = dataseries[i].at(L"timepoint");
wcout << timepoint << endl;
}
return 0;
}