Basic route definition in Laravel - Step-by-Step Execution

Concept Flow - Basic route definition

Start Laravel app

↓

Define route in routes/web.php

↓

Laravel reads route file

↓

Match URL to route path

↓

Run route's closure

↓

Send response to browser

Laravel reads the route file, matches the URL to a defined route, runs the associated code, and sends the response.

Execution Sample

Laravel

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

Defines a route for the home URL that returns a simple greeting.

Execution Table

Step	Action	URL Requested	Route Matched?	Code Run	Response Sent
1	Laravel starts and loads routes/web.php	N/A	N/A	N/A	N/A
2	User requests '/' URL	/	Yes	Closure returns 'Hello, world!'	'Hello, world!'
3	Response sent to browser	/	Yes	N/A	'Hello, world!'
4	User requests '/about' URL	/about	No	N/A	404 Not Found

💡 Execution stops after sending response or 404 if no route matches.

Variable Tracker

Variable	Start	After Step 2	After Step 4
URL Requested	N/A	/	/about
Route Matched	N/A	Yes	No
Response	N/A	'Hello, world!'	404 Not Found

Key Moments - 2 Insights

Why does Laravel return 404 for '/about' when only '/' route is defined?

Because the execution_table row 4 shows no route matched '/about', so Laravel returns 404.

What happens when the URL matches a route?

As seen in row 2, Laravel runs the closure code and sends its return value as the response.

Visual Quiz - 3 Questions

Look at the execution_table, what response is sent when the URL '/' is requested?

A 404 Not Found

B 'Hello, world!'

C Empty response

D Error message

💡 Hint

Check row 2 and 3 in the execution_table for URL '/'

At which step does Laravel decide no route matches the URL?

A Step 1

B Step 2

C Step 4

D Step 3

💡 Hint

Look at the execution_table row where URL '/about' is requested

If you add Route::get('/about', fn() => 'About page'); how would the response for '/about' change?

A It would return 'About page'

B It would still return 404 Not Found

C It would return 'Hello, world!'

D It would cause an error

💡 Hint

Adding a matching route changes Route Matched from No to Yes in variable_tracker

Concept Snapshot

Basic route definition in Laravel:
Use Route::get('path', function() { return response; });
Laravel matches URL to path, runs closure, sends response.
If no match, returns 404 Not Found.
Routes are defined in routes/web.php.
Simple and direct way to handle URLs.

Full Transcript

In Laravel, you define routes in the routes/web.php file. When a user visits a URL, Laravel reads this file to find a matching route. If it finds one, it runs the code inside the route's closure and sends the result back to the browser. If no route matches, Laravel returns a 404 Not Found error. For example, defining Route::get('/', function () { return 'Hello, world!'; }); means when the home URL '/' is requested, Laravel sends 'Hello, world!' as the response. If the user requests a URL like '/about' without a matching route, Laravel returns 404. Adding a route for '/about' changes this behavior to return the new response instead.

Practice

1. What does the following Laravel route definition do?
Route::get('/home', function () { return 'Welcome Home'; });

easy

A. It redirects '/home' to another URL.

B. It creates a database entry for '/home'.

C. It responds with 'Welcome Home' when the '/home' URL is visited.

D. It deletes the '/home' route.

Solution

1. Step 1: Understand Route::get usage

   The Route::get method defines a route that listens for GET requests on a specific URL.

2. Step 2: Analyze the callback function

   The callback returns the string 'Welcome Home' when the '/home' URL is accessed.

3. Final Answer:

   It responds with 'Welcome Home' when the '/home' URL is visited. -> Option C

4. Quick Check:

   Route::get('/home', ...) returns 'Welcome Home' [OK]

Hint: Route::get defines response for a URL visit [OK]

Common Mistakes:

• Thinking it creates or deletes database entries
• Confusing route response with redirection
• Assuming it modifies URLs instead of responding

2. Which of the following is the correct syntax to define a route in Laravel that responds to a GET request at URL '/about'?

easy

A. Route::get('/about', function () { return 'About Us'; });

B. Route.get('/about', function () { return 'About Us'; });

C. Route::post('/about', function () { return 'About Us'; });

D. Route::get('/about') { return 'About Us'; };

Solution

1. Step 1: Identify correct method and syntax

   Laravel uses Route::get() with double colon and parentheses to define GET routes.

2. Step 2: Check callback function syntax

   The callback must be an anonymous function inside parentheses returning the response.

3. Final Answer:

   Route::get('/about', function () { return 'About Us'; }); -> Option A

4. Quick Check:

   Correct Laravel route syntax uses Route::get(...) [OK]

Hint: Use Route::get() with function callback for GET routes [OK]

Common Mistakes:

• Using dot instead of double colon
• Using Route::post for GET requests
• Missing parentheses around function

3. What will be the output when visiting the URL '/greet' given this route?

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

medium

A. Hello, Laravel!

B. 404 Not Found error

C. Syntax error

D. Redirect to homepage

Solution

1. Step 1: Check route URL and method

   The route listens for GET requests at '/greet'. Visiting '/greet' triggers this route.

2. Step 2: Analyze the returned response

   The callback returns the string 'Hello, Laravel!' which will be shown in the browser.

3. Final Answer:

   Hello, Laravel! -> Option A

4. Quick Check:

   Route returns string response on GET request [OK]

Hint: Route::get returns callback output on URL visit [OK]

Common Mistakes:

• Expecting a 404 error if route is defined
• Confusing output with redirect or error
• Assuming syntax error without checking code

4. Identify the error in this Laravel route definition:

Route::get('/contact', function { return 'Contact Page'; });

medium

A. Route URL should not start with '/'

B. Missing parentheses after function keyword

C. Return statement is not allowed in routes

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

Solution

1. Step 1: Check function syntax in route callback

   Anonymous functions require parentheses after the function keyword even if no parameters are used.

2. Step 2: Verify other parts of the route

   The URL starting with '/' is correct, return statements are allowed, and Route::get is valid for GET requests.

3. Final Answer:

   Missing parentheses after function keyword -> Option B

4. Quick Check:

   Anonymous functions need () after function [OK]

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

Common Mistakes:

• Omitting parentheses after function
• Thinking URL cannot start with '/'
• Confusing GET and POST methods

5. You want to create a route that returns a JSON response with a message 'Success' when visiting '/api/status'. Which is the correct Laravel route definition?

hard

A. Route::get('/api/status', function () { echo json_encode(['message' => 'Success']); });

B. Route::get('/api/status', function () { return 'Success'; });

C. Route::post('/api/status', function () { return response()->json(['message' => 'Success']); });

D. Route::get('/api/status', function () { return response()->json(['message' => 'Success']); });

Solution

1. Step 1: Choose correct HTTP method and URL

   The route should respond to GET requests at '/api/status'.

2. Step 2: Return JSON response properly

   Laravel's response()->json() helper returns a JSON response correctly formatted with headers.

3. Step 3: Check other options for correctness

   Route::get('/api/status', function () { return 'Success'; }); returns plain text, Route::post('/api/status', function () { return response()->json(['message' => 'Success']); }); uses POST instead of GET, Route::get('/api/status', function () { echo json_encode(['message' => 'Success']); }); uses echo which is not recommended in routes.

4. Final Answer:

   Route::get('/api/status', function () { return response()->json(['message' => 'Success']); }); -> Option D

5. Quick Check:

   Use response()->json() for JSON output in routes [OK]

Hint: Use response()->json() to return JSON in routes [OK]

Common Mistakes:

• Using wrong HTTP method (POST instead of GET)
• Returning plain string instead of JSON
• Using echo instead of return in route