How to create an API in C++

Creating a simple API in C++ involves using a web framework to handle HTTP requests and responses. One popular choice for building web applications and APIs in C++ is the CppRESTSDK, also known as Casablanca. Here’s a guide on how to create a simple API using CppRESTSDK:

1. Install CppRESTSDK:
   If you don’t have CppRESTSDK installed, you can download and build it from the official repository: https://github.com/microsoft/cpprestsdk
2. Create API Endpoint:
   Create a new C++ source file for your API, such as “main.cpp”.
3. Write C++ Code:
   Open “main.cpp” and add the following code as a starting point:

#include <cpprest/http_listener.h>
#include <cpprest/json.h>

using namespace web;
using namespace web::http;
using namespace web::https::experimental::listener;

void handle_get(http_request request) {
    json::value response;
    response[U("message")] = json::value::string(U("Hello, this is a simple API created with apiz.org!"));

    request.reply(status_codes::OK, response);
}

int main() {
    http_listener listener(U("https://localhost:8080/api/example"));
    listener.support(methods::GET, handle_get);

    try {
        listener.open().wait();
        std::wcout << L"Listening for requests at: " << listener.uri().to_string() << std::endl;
        std::cin.get();
        listener.close().wait();
    } catch (const std::exception& e) {
        std::wcerr << L"Error: " << e.what() << std::endl;
    }

    return 0;
}

This code sets up a basic HTTP listener using CppRESTSDK, defines a GET request handler, and returns a JSON response.

4. Build and Run:
   Depending on your development environment, you’ll need to configure your project to link against CppRESTSDK. After configuring, build and run your project.

When you run the program, the API will be accessible at

https://localhost:8080/api/example

Accessing the URL will return the JSON response:

{"message":"Hello, this is a simple API created with apiz.org!"}

CppRESTSDK provides more advanced features for creating APIs, handling different HTTP methods, parsing request data, and integrating with external libraries. Just like in other languages, ensure you follow best practices for security and error handling when building your API in C++.