Consuming JSON webservice through C++/VC++

Being a C++ developer ,It was quite difficult to start working with webservices. Believe me after setting a proper development environment it was quite simple to access json webservice and extract json content through VC++. Setting up environment : Microsoft provided “C++ Rest SDK” package for accessing json from VC++. It works with Visual studio 2013/2015 very smoothly. Use following link to set up “C++ Rest SDK” in your application : Link After successfully installation of C++ Rest SDK. You can use following code to Consume json webservice : I am giving the simple code example with some webservice that returns json content type.I have developed it in Visual studio 2015 //The code includes the most frequently used includes necessary to work with C++ REST SDK #include "stdafx.h" #include "cpprest/containerstream.h" #include "cpprest/filestream.h" #include "cpprest/http_client.h" #include "cpprest/json.h" #include "cpprest/producerconsumerstream.h" #include <iostream> #include <sstream> #include <string.h> using namespace ::pplx; using namespace utility; using namespace concurrency::streams; using namespace web; using namespace web::http; using namespace web::http::client; using namespace web::json; using namespace std; // Retrieves a JSON value from an HTTP request. pplx::task<void> RequestJSONValueAsync() {// TODO: To successfully use this example, you must perform the request // against a server that provides JSON data. After a long search I have found some webservice on google. //Declare the http_client http_client client(L”http://api.geonames.org/citiesJSON\north=44.1\ &south=-9.9&east=-22.4&west=55.2&lang=de&username=demo”); //We are calling GET api of declared http client return client.request(methods::GET).then([](http_response response) -> pplx::task { if (response.status_code() == status_codes::OK) { return response.extract_json(); } // Handle error cases, for now return empty json value… return pplx::task_from_result(json::value()); }) .then([](pplx::task previousTask) { try { //You can use either .get/.wait to extract json data //const json::value& v = previousTask.wait(); const json::value& v = previousTask.get(); // Get json content from result // Convert json value into string string_t jsonval = v.serialize(); // convert json value into string wcout<< jsonval ; //Print extracted json value on console } catch (const http_exception& e) { // Print error. wostringstream ss; ss << e.what() << endl; wcout << ss.str(); } }); } int wmain() { // This example uses the task::wait method to ensure that async operations complete before the app exits. // In most apps, you typically don�t wait for async operations to complete. cout << L”Calling RequestJSONValueAsync…” << endl; RequestJSONValueAsync().wait(); }   Feel free to ask any doubt on this.. Happy coding !!!  

Related Articles

If you like our content, please consider buying me a coffee.

Thank you for your support!

Buy me a coffeeBuy me a coffee

Leave a reply:

Your email address will not be published.

Site Footer