Chapter 17: JSON Handling in C++

Parse, validate, and send JSON responses. In this chapter, you will learn json handling in depth with C++ code examples, explanations, and best practices.

Overview

This chapter covers json handling for Kungfu.js developers using C++. We will start with the basics, move through practical examples, and end with advanced techniques and common pitfalls.

Why This Matters

Understanding json handling is essential because it is a core part of building web applications. Every real-world app needs to handle parse, validate, and send json responses. Skipping this chapter would leave a gap in your knowledge that would cause problems later.

Code Example

Here is how to handle requests and responses in C++:

// Parse JSON body
app.post('/api/users', (req) => {
    const body = JSON.parse(req.body);
    const name = body.name;
    const email = body.email;
    
    return {
        status: 201,
        body: JSON.stringify({ id: 1, name, email })
    };
});

// Send JSON response
app.get('/api/users', (req) => {
    return {
        status: 200,
        headers: { 'content-type': 'application/json' },
        body: JSON.stringify([{ id: 1, name: 'Alice' }])
    };
});

Common Mistakes

  • Not reading the documentation: Always check the API reference when something does not work as expected.
  • Skipping security: Never disable the default middleware unless you have a very good reason. Security is not optional.
  • Not testing: Write tests for your handlers. Kungfu.js makes this easy with the built-in test utilities.

Summary

In this chapter, you learned about json handling in C++. You saw code examples, understood how things work under the hood, and learned about common mistakes to avoid.

What is Next?

In chapter 18, we will cover Form Data: Handle URL-encoded form submissions.

Previous: Response Object Deep DiveNext: Form Data