Query parameters in Laravel - Practice Problems & Coding Challenges

Challenge - 5 Problems

❓ component_behavior

intermediate

How does Laravel handle query parameters in routes?

Consider a Laravel route defined as Route::get('/search', function (Request $request) { return $request->query('q'); });. What will be the output if the URL is /search?q=books?

Laravel

Route::get('/search', function (Request $request) { return $request->query('q'); });

A "books"

B "q=books"

C null

D An error is thrown

💡 Hint

Think about how Laravel's query() method extracts values from the URL.

The query('q') method returns the value of the query parameter named 'q'. Since the URL has ?q=books, it returns "books".

📝 Syntax

intermediate

Which code correctly retrieves multiple query parameters in Laravel?

Given a URL /filter?category=books&sort=asc, which code snippet correctly retrieves both parameters?

A $params = $request->input(['category', 'sort']);

B $category = $request->query('category'); $sort = $request->query('sort');

C $category = $request->get('category'); $sort = $request->get('sort');

D $params = $request->query(); $category = $params['category']; $sort = $params['sort'];

💡 Hint

Remember that query() is the recommended method to get query parameters.

Option B uses query() to get each parameter individually, which is the correct and clear way. Option B uses input() which also works but is less specific. Option B uses get(), which also works but is less specific. Option B tries to get all parameters but then accesses them as an array which is valid but less direct.

🔧 Debug

advanced

Why does this Laravel code fail to get the query parameter?

Given the route and controller method below, why does $request->query('page') return null when accessing /items?page=2?

Route::get('/items', [ItemController::class, 'index']);

public function index(Request $request) {
    $page = $request->query('page');
    return $page;
}

A The route is missing a name, so query parameters are ignored.

B The query method only works for POST requests, not GET.

C The Request object is not imported or type-hinted correctly.

D The query parameter 'page' is not passed because the URL is malformed.

💡 Hint

Check if the Request class is properly imported and used.

If the Request class is not imported or the parameter is not type-hinted as Illuminate\Http\Request, Laravel won't inject the request object properly, so $request->query('page') returns null.

❓ state_output

advanced

What is the output of this Laravel controller method?

Consider this controller method:

public function show(Request $request) {
    $filters = $request->query();
    return json_encode($filters);
}

What is the output when accessing /show?color=red&size=medium?

A A JSON array: ["color", "red", "size", "medium"]

B An empty JSON object: "{}"

C A syntax error occurs

D {"color":"red","size":"medium"}

💡 Hint

Recall what $request->query() returns when called without arguments.

The query() method without arguments returns all query parameters as an associative array. Encoding it to JSON produces a JSON object with keys and values matching the URL parameters.

🧠 Conceptual

expert

Which statement about Laravel query parameters is true?

Choose the correct statement about how Laravel handles query parameters in HTTP requests.

A Laravel automatically merges query parameters and POST data, so <code>$request->input()</code> returns both.

B Query parameters can only be accessed via <code>$request->input()</code> and not <code>$request->query()</code>.

C The <code>$request->query()</code> method only returns query parameters if the route uses a GET method.

D Query parameters are not accessible in controller methods unless explicitly passed as route parameters.

💡 Hint

Think about how Laravel combines input sources.

Laravel's $request->input() method returns data from all input sources including query parameters and POST data. The query() method returns only query parameters. This merging happens regardless of the HTTP method.