Why routing maps URLs to logic in Laravel

Introduction

Routing connects website addresses (URLs) to the code that runs when you visit them. It helps the app know what to do for each URL.

When you want different pages or actions for different website addresses.

When you need to show a user profile page based on their ID in the URL.

When you want to handle form submissions at a specific URL.

When you want to organize your app so each URL triggers specific code.

When you want to create clean and readable URLs for your website.

Syntax

Laravel

Route::get('/url', function () {
    // logic to run
});

Use Route::get for URLs accessed with a browser (GET requests).

The first argument is the URL path, the second is the code to run.

Examples

This runs code to show 'Welcome page' when visiting the home URL.

Laravel

Route::get('/', function () {
    return 'Welcome page';
});

This captures the user ID from the URL and shows it.

Laravel

Route::get('/user/{id}', function ($id) {
    return "User ID: $id";
});

This runs code when a form sends data to '/submit' using POST.

Laravel

Route::post('/submit', function () {
    // handle form submission
});

Sample Program

This example shows three routes: home, about, and a user profile with an ID. Each URL runs different code to show a message.

Laravel

<?php
use Illuminate\Support\Facades\Route;

Route::get('/', function () {
    return 'Home page';
});

Route::get('/about', function () {
    return 'About us page';
});

Route::get('/user/{id}', function ($id) {
    return "User profile for user $id";
});

Important Notes

Routes should be defined in the routes/web.php file in Laravel.

Use curly braces {} to capture parts of the URL as variables.

Routing helps keep your app organized and easy to understand.

Summary

Routing links URLs to the code that runs for them.

It lets you create different pages and actions for different URLs.

Laravel uses simple syntax to define routes with Route::get or Route::post.

Practice

1. What is the main purpose of routing in Laravel?

easy

A. To store user data in the database

B. To connect URLs to the code that should run

C. To style the webpage with CSS

D. To send emails automatically

Solution

1. Step 1: Understand routing role

   Routing connects a web address (URL) to the specific code that runs when that address is visited.

2. Step 2: Compare options

   Only To connect URLs to the code that should run describes this linking of URLs to code. Other options describe unrelated tasks.

3. Final Answer:

   To connect URLs to the code that should run -> Option B

4. Quick Check:

   Routing = URL to code link [OK]

Hint: Routing links URLs to code, not data or styles [OK]

Common Mistakes:

• Confusing routing with database storage
• Thinking routing styles pages
• Assuming routing sends emails

2. Which of the following is the correct Laravel syntax to define a route for a GET request to '/home'?

easy

A. Route::post('/home', function () { return 'Home'; });

B. Route::delete('/home', function () { return 'Home'; });

C. Route::put('/home', function () { return 'Home'; });

D. Route::get('/home', function () { return 'Home'; });

Solution

1. Step 1: Identify HTTP method for route

   GET requests retrieve data or pages, so Route::get is used for '/home'.

2. Step 2: Check syntax correctness

   Route::get('/home', function () { return 'Home'; }); uses Route::get with a closure returning 'Home', which is correct syntax.

3. Final Answer:

   Route::get('/home', function () { return 'Home'; }); -> Option D

4. Quick Check:

   GET route syntax = Route::get('/home', function () { return 'Home'; }); [OK]

Hint: Use Route::get for GET URLs, not post/put/delete [OK]

Common Mistakes:

• Using Route::post for GET requests
• Mixing HTTP methods and routes
• Incorrect closure syntax

3. Given this route definition:

Route::get('/greet', function () { return 'Hello, Laravel!'; });

What will a user see when visiting the URL '/greet'?

medium

A. A blank page

B. 404 Not Found error

C. Hello, Laravel!

D. An internal server error

Solution

1. Step 1: Analyze route action

   The route returns the string 'Hello, Laravel!' when '/greet' is visited.

2. Step 2: Determine output on visiting URL

   Visiting '/greet' triggers the route and shows the returned string as page content.

3. Final Answer:

   Hello, Laravel! -> Option C

4. Quick Check:

   Route returns string = 'Hello, Laravel!' [OK]

Hint: Route returns string shown on page at URL [OK]

Common Mistakes:

• Expecting a 404 error for defined route
• Thinking route returns blank page
• Confusing server error with route output

4. Identify the error in this Laravel route:

Route::get('/user', function { return 'User page'; });

medium

A. Missing parentheses after function keyword

B. Route URL should be '/users' not '/user'

C. Return statement cannot be used in routes

D. Route::get should be Route::post for pages

Solution

1. Step 1: Check function syntax

   Anonymous functions require parentheses after 'function', even if empty.

2. Step 2: Identify syntax error

   The code misses '()' after 'function', causing a syntax error.

3. Final Answer:

   Missing parentheses after function keyword -> Option A

4. Quick Check:

   Anonymous function needs () after function [OK]

Hint: Always add () after function keyword in closures [OK]

Common Mistakes:

• Omitting parentheses after function
• Changing URL unnecessarily
• Misunderstanding return usage in routes

5. You want to create two routes: one for showing a form at '/form' and one for processing the form submission at '/submit'. Which routing setup correctly maps URLs to logic in Laravel?

hard

A. Route::get('/form', function () { return view('form'); });\nRoute::post('/submit', function () { return 'Form submitted'; });

B. Route::post('/form', function () { return view('form'); });\nRoute::get('/submit', function () { return 'Form submitted'; });

C. Route::get('/submit', function () { return view('form'); });\nRoute::post('/form', function () { return 'Form submitted'; });

D. Route::get('/form', function () { return 'Form submitted'; });\nRoute::post('/submit', function () { return view('form'); });

Solution

1. Step 1: Identify HTTP methods for form pages

   The form page is shown with GET (to display), and submission uses POST (to send data).

2. Step 2: Match routes to URLs and methods

   Route::get('/form', function () { return view('form'); });\nRoute::post('/submit', function () { return 'Form submitted'; }); correctly uses Route::get for '/form' to show the form view, and Route::post for '/submit' to handle submission.

3. Final Answer:

   Route::get('/form', function () { return view('form'); }); Route::post('/submit', function () { return 'Form submitted'; }); -> Option A

4. Quick Check:

   GET shows form, POST submits form [OK]

Hint: Use GET for showing forms, POST for submitting forms [OK]

Common Mistakes:

• Using POST to show form page
• Using GET to submit form data
• Mixing URLs and HTTP methods incorrectly