Uploading files in Laravel - Practice Problems & Coding Challenges

Challenge - 5 Problems

❓ component_behavior

intermediate

What happens when a file is uploaded without validation?

Consider a Laravel controller method that handles file uploads but does not validate the file type or size. What is the likely outcome when a user uploads a very large or unsupported file?

Laravel

public function upload(Request $request) {
    $path = $request->file('photo')->store('photos');
    return 'File uploaded to ' . $path;
}

A The file is saved regardless of type or size, which may cause storage or security issues.

B Laravel automatically rejects files larger than 2MB without any code.

C The upload fails silently and no file is saved.

D Laravel throws a validation error automatically for unsupported file types.

💡 Hint

Think about what Laravel does by default if you don't add validation rules.

Without explicit validation, Laravel will accept and store any uploaded file regardless of size or type. This can lead to security risks or storage problems.

📝 Syntax

intermediate

Which code correctly stores an uploaded file with a custom filename?

Given a file input named 'document', which Laravel code snippet correctly stores the file with a custom name 'user_123.pdf' in the 'docs' folder?

A $request->file('document')->storeAs('docs', 'user_123.pdf');

B $request->file('document')->store('docs/user_123.pdf');

C $request->file('document')->move('docs', 'user_123.pdf');

D $request->file('document')->saveAs('docs', 'user_123.pdf');

💡 Hint

Look for the Laravel method that allows specifying a custom filename.

The storeAs method stores the file in the specified folder with the given filename. The store method does not accept a filename, move requires an absolute directory path, and saveAs does not exist.

🔧 Debug

advanced

Why does this file upload code fail with 'Call to a member function store() on null'?

Examine the following Laravel controller method:

public function upload(Request $request) {
    $path = $request->file('photo')->store('images');
    return $path;
}

When submitting the form, the error occurs. What is the cause?

A The file is too large and Laravel rejects it silently.

B The 'photo' input name does not match the file input name in the form.

C The storage folder 'images' does not exist and causes the error.

D The form does not have <code>enctype="multipart/form-data"</code>, so no file is sent.

💡 Hint

Check the HTML form attributes required for file uploads.

If the form lacks enctype="multipart/form-data", the file input will not be sent, so $request->file('photo') returns null, causing the error.

❓ state_output

advanced

What is the value of $filename after this code runs?

Consider this Laravel code snippet:

$file = $request->file('avatar');
$filename = time() . '.' . $file->getClientOriginalExtension();
$file->storeAs('avatars', $filename);

Assuming the uploaded file is named 'photo.png' and the current UNIX timestamp is 1680000000, what is the value of $filename?

A avatars/1680000000.png

B photo.png

C 1680000000.png

D 1680000000.photo.png

💡 Hint

Look at how the filename is constructed using time() and the file extension.

The filename is the current timestamp plus a dot plus the original file extension. Since the file is 'photo.png', the extension is 'png'.

🧠 Conceptual

expert

Which Laravel feature helps prevent overwriting files with the same name during upload?

When multiple users upload files with the same original filename, what Laravel feature or approach ensures each file is saved uniquely without overwriting?

A Using <code>storeAs()</code> with the original filename to keep names consistent.

B Using <code>store()</code> method which generates a unique ID for the filename automatically.

C Manually renaming files with <code>getClientOriginalName()</code> before storing.

D Saving files in the public folder without any naming changes.

💡 Hint

Think about which method Laravel uses to avoid filename collisions automatically.

The store() method generates a unique filename automatically to prevent overwriting. Using storeAs() with original names risks overwriting. Manual renaming requires extra code. Saving in public folder without renaming does not prevent overwrites.