Node.js Web Server Basics

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Questions and Answers

What does req.url provide when logging an incoming request?

The entire HTTP request data
The HTTP method used in the request
The URL path of the request (correct)
The headers of the request

Which of the following methods would be used to send response body data in Node.js?

res.output()
res.display()
res.send()
res.write() (correct)

What purpose does res.setHeader() serve when sending a response?

To log the response to the server console
To inform the browser about the type of content (correct)
To end the response prematurely
To add new data to the response body

What will happen if you try to write to the response after calling res.end()?

An error will occur (B) Signup and view all the answers

Which output can you expect when navigating to http://localhost:3000 after starting the server?

Hello from my Node.js Server! (A) Signup and view all the answers

In web applications, what does a route represent?

A specific URL path and HTTP method (D) Signup and view all the answers

Which HTTP method would typically not be used with res.write() when creating a route?

CONNECT (C) Signup and view all the answers

What does the req.headers object contain?

An object with the request headers (C) Signup and view all the answers

What should the server do when it receives a request to a URL path that is not '/'?

Return a default HTML page (D) Signup and view all the answers

What is the purpose of routes in a web application?

They represent different endpoints that users can request. (D) Signup and view all the answers

How does the server indicate that the response content type is HTML?

By setting the Content-Type header to text/html (B) Signup and view all the answers

What method should be used to capture the part of the URL after the hostname in a Node.js server?

req.url (A) Signup and view all the answers

What is the purpose of calling res.end() in the server's response?

To end the response and send it back to the client (D) Signup and view all the answers

Which method is used to handle only POST requests to the /message route?

if statement checking url and method (A) Signup and view all the answers

What does the action attribute of the HTML form indicate?

The destination route for the form data. (D) Signup and view all the answers

What status code is set to indicate a redirect to the user?

302 (D) Signup and view all the answers

What HTTP method does the HTML form use to send data to the /message route?

POST (D) Signup and view all the answers

What should be checked to execute specific code for the home route?

req.url is equal to '/' (B) Signup and view all the answers

What Node.js module is necessary for writing data to a file?

fs (B) Signup and view all the answers

What does the example suggest should be returned after sending the HTML response in a Node.js server?

return res.end() (B) Signup and view all the answers

What command is used to start the server in the terminal?

node app.js (A) Signup and view all the answers

What would happen if the URL path does not match '/' in the server code?

The code will continue executing to the next route check. (C) Signup and view all the answers

What does the writeFileSync method do in the context of file handling?

Creates a new file or overwrites an existing one (D) Signup and view all the answers

What type of content is being sent in response to a request to the root route?

HTML Form (B) Signup and view all the answers

What is the purpose of restarting the server after making changes to the code?

To ensure that the new code is executed. (C) Signup and view all the answers

How does Node.js handle incoming data from HTTP requests?

It processes data in small chunks using streams. (B) Signup and view all the answers

What is the role of the 'on(data)' event listener in Node.js?

To capture incoming data chunks as they arrive. (D) Signup and view all the answers

What happens when all data chunks have been received in Node.js?

The end event is triggered, indicating all data has been captured. (C) Signup and view all the answers

What does the Buffer.concat() method accomplish in Node.js?

It combines multiple chunks into a single buffer for processing. (B) Signup and view all the answers

Which method is used to initiate the handling of incoming data chunks in Node.js?

req.on('data', ...) (C) Signup and view all the answers

What does the 'body' array represent in the handling of data chunks?

An array collecting incoming data chunks. (C) Signup and view all the answers

What is the primary advantage of stream processing in Node.js for large payloads?

It enables processing to begin before the entire payload is received. (D) Signup and view all the answers

What is the primary purpose of the requestHandler function in routes.js?

To manage routing and handle requests in the Node.js server. (D) Signup and view all the answers

What does the server respond with when a POST request is sent to the '/message' route?

The server saves the message to a file and redirects to the home page. (D) Signup and view all the answers

Which Node.js method is used to read the data chunks sent in a POST request?

req.on('data') (D) Signup and view all the answers

What should be the content type of the response when handling a request that does not match any specific route?

text/html (A) Signup and view all the answers

Which line of code properly exports the requestHandler function for use in other files?

module.exports = requestHandler; (A) Signup and view all the answers

What does the server.listen(3000) line do in app.js?

It specifies the port number the server will listen to for incoming connections. (A) Signup and view all the answers

What will happen if the Buffer.concat(body).toString() method is not correctly used in the POST handling?

Data will not be read from the request body properly. (A) Signup and view all the answers

What message is displayed to the user when accessing the root URL ('/') of the server?

Enter Message (C) Signup and view all the answers

Study Notes

Logging Incoming Requests

req.url logs the URL path of the incoming request.
req.method logs the HTTP method of the incoming request.
req.headers logs an object containing the headers of the incoming request.

Sending Responses

res.setHeader('Content-Type', 'text/html'): sets the Content-Type header to text/html, informing the browser that the response contains HTML content.
res.write(): sends chunks of data as part of the response body.
res.end(): signals to Node.js that the response is complete and can be sent back to the client.

Routing

Routes are specific endpoints that a web application can respond to.
Routes represent a specific URL path and HTTP method.
Routes act as entry points to the application and determine how it responds to client requests to particular endpoints.

Handling Requests

req.url is used to capture the part of the URL after the hostname.
If statements are used to check the URL path and determine which route to handle.

Serving HTML Form

An HTML form is sent to the root route (/).
The form uses POST method to send data to the '/message' route.

Redirecting Requests

res.statusCode = 302: sets the status code to 302, indicating a redirect.
res.setHeader('Location', '/'): sets the Location header to '/', redirecting the user to the root route.

Writing Data to a File

fs.writeFileSync: creates a new file or overwrites an existing one.
fs.writeFile: writes data to a file.

Handling Incoming Data with Streams and Buffers

Streams: Node.js handles incoming data as a stream, processing it in small chunks.
Buffers: act as temporary holding areas for data chunks and collect them until ready for processing.
Buffer.concat(): combines all data chunks into a single buffer.

Node Modules System

require: import a file from another file.
module.exports: exports a function or variable to be used by other files.
File Structure: Separate code into multiple files for better organization and maintainability.

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Description

This quiz covers the fundamental concepts of handling incoming requests and sending responses in Node.js. You'll explore how to log request details, set response headers, and implement routing effectively. Test your knowledge on the key components that make up a basic web server using Node.js.