Why building HTTP servers matters in Node.js - Challenge Your Understanding

Challenge - 5 Problems

🧠 Conceptual

intermediate

Why do we use HTTP servers in Node.js?

Which of the following best explains why building HTTP servers is important in Node.js?

A HTTP servers are only used to send emails from Node.js.

B HTTP servers allow Node.js to listen for and respond to web requests, enabling web applications to work.

C HTTP servers are used to store files on the computer permanently.

D HTTP servers help Node.js to run desktop applications faster.

💡 Hint

Think about what happens when you open a website in your browser.

HTTP servers listen for requests from browsers or other clients and send back responses like web pages or data. This is how websites and web apps work.

❓ component_behavior

intermediate

What happens when a Node.js HTTP server receives a request?

Consider a simple Node.js HTTP server. What does the server do when it receives a request from a browser?

A It processes the request and sends back a response like a web page or data.

B It immediately shuts down to save resources.

C It ignores the request and waits for a different type of input.

D It sends the request to the operating system to handle.

💡 Hint

Think about what a web server's job is when you visit a website.

The server listens for requests, processes them, and sends back responses so the browser can show the web page or data.

📝 Syntax

advanced

Identify the correct way to create a basic HTTP server in Node.js

Which code snippet correctly creates a simple HTTP server that responds with 'Hello World'?

Node.js

const http = require('http');

// Choose the correct server creation code below

A const server = http.createServer((req, res) => { res.write('Hello World'); res.end(); });

B const server = http.createServer((req, res) => { res.send('Hello World'); });

C const server = http.createServer((request, response) => { response.writeHead(200); response.end('Hello World'); });

D const server = http.createServer((req, res) => { res.write('Hello World'); })

💡 Hint

Remember to send a status code and end the response properly.

Option C correctly sets the status code with writeHead and ends the response with the message. Option C misses the status code. Option C uses a method not available on the response object. Option C does not end the response, so the client waits forever.

🔧 Debug

advanced

Why does this Node.js HTTP server code cause the browser to hang?

Look at this code snippet: const http = require('http'); const server = http.createServer((req, res) => { res.write('Loading...'); }); server.listen(3000); Why does the browser keep loading and never show the response?

A Because the callback function is missing the request parameter.

B Because the server.listen port is incorrect.

C Because res.write() cannot be used in HTTP servers.

D Because res.end() is missing, so the response never finishes.

💡 Hint

Think about how HTTP responses are completed.

The response must be ended with res.end() to tell the browser the message is complete. Without it, the browser waits forever.

❓ state_output

expert

What is the output when multiple requests hit this Node.js HTTP server?

Consider this server code: const http = require('http'); let count = 0; const server = http.createServer((req, res) => { count++; res.writeHead(200, {'Content-Type': 'text/plain'}); res.end(`Request number: ${count}`); }); server.listen(3000); If three requests come in one after another, what will the third request receive as a response?

A "Request number: 3"

B "Request number: 1"

C "Request number: 0"

D An error because count is not reset

💡 Hint

Think about how the variable count changes with each request.

The variable count increments with each request, so the third request gets the value 3.