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Create Scalable APIs Using AI

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  • Skill path

    AI-Assisted Back-End Development

    Learn back-end development with AI tools. Build APIs, work with Node.js, and manage databases using AI coding agents for faster workflows.
    • Includes 2 Courses
    • With Certificate
    • Intermediate.
      4 hours

Express.js Prompt Structure

When creating prompts for coding in Express.js, it’s essential to outline the requirements such as core behavior and error handling. Define constraints to ensure secure code and include integration details for coherent output. This structure guides developers in generating precise and reliable code.

// Example of a well-structured Express.js prompt
const express = require('express');
const app = express();


// Core Behavior: Simple GET request
app.get('/', (req, res) => {
  res.send('Hello World!');
});


// Error Handling: 404 for non-existing routes
app.use((req, res, next) => {
  res.status(404).send('Not Found');
});


// Start server
const PORT = process.env.PORT || 3000;
app.listen(PORT, () => {
  console.log(`Server running on port ${PORT}`);
});

REST API Contract

Understanding an API contract is crucial in REST API design. It details every endpoint’s request structure, including parameters, properties, and validation rules, alongside the response format and error handling. This provides a clear blueprint for developers, enhancing consistent communication.

{
  "request": {
    "path": "/users",
    "method": "POST",
    "body": {
      "name": "string",  // Required
      "email": "string", // Required
      "age": "integer"   // Optional
    }
  },
  "response": {
    "status": 201,
    "body": {
      "id": "string",
      "created_at": "datetime"
    }
  },
  "errors": [
    {
      "code": "400",
      "message": "Invalid 'email' format."
    }
  ]
}

Express.js Endpoint

An endpoint in Express.js acts as a route handler. It processes HTTP requests on specific paths by checking data validity, executing business logic, and returning a status-coded response. These endpoints form the core of any API developed using Express.js framework.

const express = require('express');
const app = express();


// Define an endpoint
app.get('/api/data', (req, res) => {
  const data = { message: 'Hello from the server!' };
  res.status(200).json(data);
});


app.listen(3000, () => {
  console.log('Server is running on port 3000');
});

Express.js Middleware

Middleware in Express.js acts as a request interceptor. It’s a function that processes incoming requests before they hit route handlers. Middleware can perform actions like logging details, parsing request bodies, or managing errors.

const express = require('express');
const app = express();


// Logging middleware
app.use((req, res, next) => {
  console.log(`${req.method} request for '${req.url}'`);
  next();
});


app.get('/', (req, res) => {
  res.send('Hello World!');
});


app.listen(3000, () => {
  console.log('Server is running on port 3000');
});

JWT Authentication

JWT or JSON Web Token is a compact, URL-safe way to represent claims between two parties. With a successful login, a user is issued a signed JWT which contains user information. This token is then verified by the server for its signature and expiration, ensuring secure access to protected resources.

// Example of verifying JWT in Node.js
const jwt = require('jsonwebtoken');


const token = "your_jwt_token_here";
const secret = "your_secret_key";


// Verifying the token
jwt.verify(token, secret, (err, decoded) => {
  if (err) {
    console.log('Token is not valid', err);
  } else {
    console.log('Token is valid', decoded);
  }
});

OpenAPI Overview

OpenAPI is a standardized format for detailing API endpoints, HTTP methods, request parameters, request body schemas, response schemas, and status codes. This format ensures consistency, making it easier to build and integrate APIs. OpenAPI documentation improves API usability by providing a clear, detailed blueprint for developers.

openapi: "3.0.0"
info: 
  title: Sample API
  description: A sample API to illustrate OpenAPI.
  version: "1.0.0"
paths:
  /items:
    get:
      summary: List all items
      responses:
        "200":
          description: A list of items
          content: 
            application/json:
              schema:
                type: array
                items: 
                  type: object
                  properties: 
                    id: 
                      type: integer
                    name: 
                      type: string

Learn more on Codecademy

  • Skill path

    AI-Assisted Back-End Development

    Learn back-end development with AI tools. Build APIs, work with Node.js, and manage databases using AI coding agents for faster workflows.
    • Includes 2 Courses
    • With Certificate
    • Intermediate.
      4 hours
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