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Postman

In this session, we will explore Postman, a powerful tool for testing and interacting with your Node.js APIs. Postman makes it easy to send requests, inspect responses, and test your API endpoints.

What is Postman?​

Postman is a popular API client that allows you to:

  • Send HTTP requests: You can send GET, POST, PUT, DELETE, and other HTTP requests to your Node.js server.

  • Inspect responses: Postman displays the response data in a user-friendly format, making it easy to understand the server's response.

  • Test API endpoints: You can create tests to automate the validation of API responses.

  • Organize requests: Postman lets you organize your requests into collections, making it easy to manage and share them.

Installation​

First, you need to install Postman. You can download it from the official website.

Sending a GET Request​

Let's start with a simple example. We will send a GET request to a sample Node.js server running on your local machine.

Live Code Example:

// Sample Node.js server
const express = require('express');
const app = express();

app.get('/api/data', (req, res) => {
  res.json({ message: 'Hello from Node.js' });
});

app.listen(3000, () => {
  console.log('Server is running on port 3000');
});
  1. Open Postman.
  2. Create a new request.
  3. Set the request type to GET.
  4. Enter the URL: http://localhost:3000/api/data.
  5. Click "Send."

You should receive a response with the message "Hello from Node.js."

Testing an API Endpoint​

Postman allows you to write tests to verify the responses from your API. Let's create a simple test:

Live Code Example:

// Sample Node.js server response
const response = {
  message: 'Hello from Node.js',
};

// Postman test script
tests["Response status is 200"] = responseCode.code === 200;
tests["Response contains 'Hello from Node.js'"] = responseBody.has('Hello from Node.js');
  1. In Postman, go to the "Tests" tab of your request.
  2. Enter the test script as shown above.
  3. Click "Send."

Postman will run the tests and display the results.

This is just the beginning of what you can do with Postman. You can explore more features like environment variables, collections, and automation to streamline your API development and testing process.

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Postman - API Testing and Documentation​

Introduction to Postman​

  • What is Postman?
  • Why is Postman essential for API development?
  • Installation and setup of Postman.

Sending GET Requests​

  • Using Postman to send GET requests to a REST API.
  • Explanation of GET requests and their use cases.
  • Live example: Retrieve data from a public API (e.g., JSONPlaceholder).

Sending POST Requests​

  • Creating and sending POST requests to add data.
  • Explaining the concept of POST requests for data creation.
  • Live example: Create a new resource in your Node.js application using Postman.

Sending PUT Requests​

  • Using Postman to send PUT requests to update existing data.
  • Understanding the purpose of PUT requests in RESTful APIs.
  • Live example: Update an existing resource in your Node.js application using Postman.

Sending DELETE Requests​

  • How to send DELETE requests using Postman to remove data.
  • Discussing DELETE requests and their significance.
  • Live example: Delete a resource in your Node.js application using Postman.

Authentication in Postman​

  • Configuring authentication in Postman for secured APIs.
  • Explaining different authentication methods (e.g., Basic Auth, Bearer Token).
  • Live example: Testing authenticated routes in your Node.js application.

Writing Tests in Postman​

  • Creating tests in Postman to automate API testing.
  • Demonstrating how to write test scripts using JavaScript in Postman.
  • Live example: Writing a test script to verify API responses.

Documenting APIs with Postman​

  • How to use Postman for API documentation.
  • Generating and sharing documentation with team members.
  • Live example: Creating API documentation for your Node.js project.

Collection and Environment Variables​

  • Managing collections and environment variables in Postman.
  • Streamlining testing and development workflows with variables.
  • Live example: Using variables to switch between development and production environments.