Controller methods and actions in Laravel - Practice Problems & Coding Challenges

Challenge - 5 Problems

❓ component_behavior

intermediate

What is the output of this Laravel controller method?

Consider this controller method in Laravel:

public function show($id) {
    return response()->json(['id' => $id, 'status' => 'found']);
}

What will be the JSON response when calling show(5)?

Laravel

public function show($id) {
    return response()->json(['id' => $id, 'status' => 'found']);
}

A {"id":"5","status":"found"}

B {"id":5,"status":"found"}

C {"id":5,"status":"not found"}

D SyntaxError

💡 Hint

Remember that the $id parameter is passed as a string from the route and quoted in the JSON.

The method returns a JSON response with the id key set to the integer passed and status set to 'found'. Option B matches this exactly.

❓ lifecycle

intermediate

Which controller method is called when a resource is created in Laravel?

In a Laravel resource controller, which method handles the HTTP POST request to create a new resource?

A store()

B create()

C edit()

D update()

💡 Hint

Think about which method processes the form submission to save data.

The store() method handles POST requests to save new resources. create() shows the form, but does not save.

📝 Syntax

advanced

What error does this Laravel controller method produce?

Examine this controller method:

public function update(Request $request, $id) {
    $data = $request->all;
    Model::find($id)->update($data);
    return redirect()->route('items.index');
}

What error will occur when this method runs?

Laravel

public function update(Request $request, $id) {
    $data = $request->all;
    Model::find($id)->update($data);
    return redirect()->route('items.index');
}

A SyntaxError: Unexpected token

B No error, updates successfully

C Error: Method all() not found

D TypeError: Argument 1 passed to update() must be array, null given

💡 Hint

Check how the request data is accessed.

The code uses $request->all without parentheses, so it is treated as a property, which is null. The update method expects an array, causing a TypeError.

🔧 Debug

advanced

Why does this Laravel controller method cause a runtime error?

Look at this method:

public function destroy($id) {
    $item = Model::findOrFail($id);
    $item->delete;
    return redirect()->back();
}

What causes the error when calling destroy(10)?

Laravel

public function destroy($id) {
    $item = Model::findOrFail($id);
    $item->delete;
    return redirect()->back();
}

A No error, deletes successfully

B ModelNotFoundException if id 10 does not exist

C Error: Call to undefined method delete (missing parentheses)

D SyntaxError: Unexpected token

💡 Hint

Check how the delete method is called.

The code uses $item->delete without parentheses, so it references the method but does not call it. This causes a runtime error.

🧠 Conceptual

expert

What is the value of $result after this Laravel controller action?

Given this controller method:

public function index() {
    $items = Model::where('active', true)->get();
    $result = $items->count();
    return view('items.index', compact('items'));
}

What is the value of $result if there are 7 active items in the database?

Laravel

public function index() {
    $items = Model::where('active', true)->get();
    $result = $items->count();
    return view('items.index', compact('items'));
}

A 7

B 0

C null

D Error: count() method not found

💡 Hint

The get() method returns a collection of matching items.

The count() method on the collection returns the number of items, which is 7 in this case.