Route parameters in Laravel - Practice Problems & Coding Challenges

Challenge - 5 Problems

❓ component_behavior

intermediate

What is the output of this Laravel route with parameter?

Consider this Laravel route definition:

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

What will be the output when visiting URL /user/42?

Laravel

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

A User ID: 42

B User ID: {id}

C User ID: $id

D 404 Not Found

💡 Hint

Route parameters are passed as variables to the callback function.

The {id} in the route URL is captured and passed as the $id argument to the closure. So visiting /user/42 sets $id to 42, which is returned in the string.

📝 Syntax

intermediate

Which route definition correctly uses an optional parameter?

In Laravel, how do you define a route with an optional parameter named page?

A Route::get('/posts/{page}', function ($page = 1) { return $page; });

B Route::get('/posts/{page?}', function ($page = 1) { return $page; });

C Route::get('/posts/{page?}', function ($page) { return $page; });

D Route::get('/posts/{page?}', function () { return $page; });

💡 Hint

Optional parameters use a question mark and default value in the function.

The question mark after {page} makes it optional. The function must provide a default value for $page to avoid errors when the parameter is missing.

🔧 Debug

advanced

Why does this route cause an error?

Given this route:

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

What error will occur when visiting /product/5?

Laravel

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

A Syntax error due to missing parameter

B 404 Not Found error

C Undefined variable $id error

D No error, outputs 'Product ID: 5'

💡 Hint

Check if the route parameter is passed to the function.

The route expects a parameter {id}, but the closure does not accept any arguments. So $id is undefined inside the function, causing an error.

🧠 Conceptual

advanced

What happens if two routes conflict with parameters?

Consider these two routes:

Route::get('/user/{name}', function ($name) { return "User: $name"; });
Route::get('/user/profile', function () { return "Profile page"; });

What will happen when visiting /user/profile?

A Laravel throws a route conflict error

B The second route matches and outputs 'Profile page'

C 404 Not Found error

D The first route matches and outputs 'User: profile'

💡 Hint

Routes are matched in the order they are defined.

The first route with {name} matches any string after /user/, including 'profile'. So it captures 'profile' as $name and returns 'User: profile'. The second route is never reached.

❓ state_output

expert

What is the output of this route with multiple parameters and constraints?

Given this route:

Route::get('/order/{id}/{status}', function ($id, $status) { return "Order $id is $status"; })->where(['id' => '[0-9]+', 'status' => 'pending|shipped']);

What is the output when visiting /order/123/shipped and /order/abc/pending respectively?

Laravel

Route::get('/order/{id}/{status}', function ($id, $status) { return "Order $id is $status"; })->where(['id' => '[0-9]+', 'status' => 'pending|shipped']);

A First URL: 'Order 123 is shipped', Second URL: 404 Not Found

B First URL: 404 Not Found, Second URL: 'Order abc is pending'

C Both URLs output the order status string

D Both URLs return 404 Not Found

💡 Hint

Route constraints limit which URLs match the route.

The 'id' must be digits only, so '123' matches but 'abc' does not. The 'status' must be 'pending' or 'shipped'. So the first URL matches and returns the string. The second URL does not match the constraints and returns 404.

Practice

1. What is the purpose of route parameters in Laravel?

easy

A. To define middleware for routes

B. To capture dynamic values from the URL

C. To set HTTP methods for routes

D. To create static pages only

Solution

1. Step 1: Understand route parameters

   Route parameters are placeholders in the URL that capture dynamic values.

2. Step 2: Identify their use

   They allow the app to receive values from the URL to use in controllers or views.

3. Final Answer:

   To capture dynamic values from the URL -> Option B

4. Quick Check:

   Route parameters = dynamic URL values [OK]

Hint: Route parameters capture values inside {} in URLs [OK]

Common Mistakes:

• Confusing parameters with middleware
• Thinking parameters set HTTP methods
• Assuming parameters create static pages

2. Which of the following is the correct syntax to define a required route parameter named id in Laravel?

easy

A. Route::get('/user/{id}', function ($id) {});

B. Route::get('/user/:id', function ($id) {});

C. Route::get('/user/[id]', function ($id) {});

D. Route::get('/user/<id>', function ($id) {});

Solution

1. Step 1: Recall Laravel route parameter syntax

   Laravel uses curly braces {} to define route parameters.

2. Step 2: Match syntax with options

   Only Route::get('/user/{id}', function ($id) {}); uses curly braces correctly: '/user/{id}'.

3. Final Answer:

   Route::get('/user/{id}', function ($id) {}); -> Option A

4. Quick Check:

   Curly braces = route parameters [OK]

Hint: Use curly braces {} for parameters in routes [OK]

Common Mistakes:

• Using colon : instead of curly braces
• Using square brackets [] or angle brackets <>
• Forgetting to pass parameter to callback

3. Given the route definition Route::get('/post/{postId}', function ($postId) { return 'Post ID: ' . $postId; });, what will be the output when visiting /post/42?

medium

A. Post ID:

B. Post ID: {postId}

C. Post ID: 42

D. Error: Missing parameter

Solution

1. Step 1: Understand parameter passing

   The URL segment '42' matches the {postId} parameter and is passed to the function as $postId.

2. Step 2: Evaluate the return statement

   The function returns 'Post ID: ' concatenated with the value of $postId, which is '42'.

3. Final Answer:

   Post ID: 42 -> Option C

4. Quick Check:

   URL value passed to parameter = output [OK]

Hint: URL value replaces parameter in function automatically [OK]

Common Mistakes:

• Expecting literal {postId} in output
• Thinking parameter is optional by default
• Forgetting to concatenate parameter value

4. What is wrong with this route definition? Route::get('/product/{id?}', function () { return 'Product ID: ' . $id; });

medium

A. The parameter $id is missing in the function signature

B. Optional parameters cannot be used in routes

C. Curly braces should be replaced with parentheses

D. Route URL should not contain parameters

Solution

1. Step 1: Check function parameters

   The route URL defines an optional parameter {id?}, but the function does not accept $id as an argument.

2. Step 2: Understand parameter passing

   Laravel passes route parameters to the function, so $id must be declared to use it.

3. Final Answer:

   The parameter $id is missing in the function signature -> Option A

4. Quick Check:

   Function must accept route parameters [OK]

Hint: Function must list all route parameters as arguments [OK]

Common Mistakes:

• Omitting parameters in function
• Thinking optional parameters are disallowed
• Using wrong syntax for optional parameters

5. How can you define a route with an optional parameter category that defaults to 'all' if not provided, and use it inside the route callback?

hard

A. Route::get('/items/{category?}', function ($category) { return 'Category: ' . $category; });

B. Route::get('/items/{category}', function () { return 'Category: all'; });

C. Route::get('/items', function ($category = 'all') { return 'Category: ' . $category; });

D. Route::get('/items/{category?}', function ($category = 'all') { return 'Category: ' . $category; });

Solution

1. Step 1: Define optional parameter in route

   Use curly braces with a question mark {category?} to make the parameter optional.

2. Step 2: Set default value in function

   Assign a default value 'all' to $category in the function signature to handle missing parameter.

3. Final Answer:

   Route::get('/items/{category?}', function ($category = 'all') { return 'Category: ' . $category; }); -> Option D

4. Quick Check:

   Optional parameter + default value = Route::get('/items/{category?}', function ($category = 'all') { return 'Category: ' . $category; }); [OK]

Hint: Use {param?} and default value in function for optional params [OK]

Common Mistakes:

• Not setting default value in function
• Omitting ? in route parameter
• Defining parameter but not using it