cpprestsdk

example of cpprestsdk using the gw2 rest api

What this example mainly offers:

This example of cpprestsdk offers a function for sending an http GET request to the given uri and extract the json from the http body

this function has the following prototype:

/// @brief:		send an http GET request to the given uri and extract the json from the http body
/// @arg0:		uri u		the uri the http GET request is being sent to
/// @return:	the ppl::task of template type web::json::value
pplx::task<web::json::value> json_request_task(uri u);

you can retrieve the pplx::task from the json_request_task-function with the following code snippet:

// retrieve the item-list from gw2 rest api
auto requested_task = json_request_task(builder.to_uri());

after retrieving the pplx::task this way you can add continuation chains with the .then method, like following code snippet:

.then([=](pplx::task<web::json::value> previousTask)	// capture all local vars into lambda
	{
		// get the JSON value from the task and display content from it
		const web::json::value& json_value = previousTask.get();	// web::json::value     // Wait for the tasks to finish 

		json_value.serialize(std::wcout);

		const web::json::array ar = json_value.as_array();

		// iterate over each items properties from gw2 rest api
		std::for_each(
			ar.cbegin(),
			ar.cend(),
			[&](web::json::value jv)
			{
				std::wout << jv.to_string() << std::endl;
			}
		);
	}
);

also exception handling can be handled in another chain contination:

.then([=]()
	{
		try
		{ 
			// exceptions from ascending tasks are passed down here for error handling
		}
		catch (json::json_exception &je)
		{
			std::cerr << "JSON exception occurred:" << je.what() << "\n";
		}
		catch (pplx::task_canceled &tc)
		{
			std::cerr << "Task canceled exception occurred:" << tc.what() << "\n";
		}
		catch (const std::exception &e)
		{
			std::cerr << "Error exception occurred:" << e.what() << "\n";
		}
	}
);