File uploads in Laravel - Practice Problems & Coding Challenges

Challenge - 5 Problems

❓ component_behavior

intermediate

What happens when a file is uploaded without validation in Laravel?

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

<?php
public function upload(Request $request) {
    $path = $request->file('document')->store('uploads');
    return back()->with('message', 'File uploaded!');
}

A The upload fails silently and no file is stored.

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

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

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

💡 Hint

Think about what happens if you don't tell Laravel to check the file before saving.

Without explicit validation, Laravel will 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 in Laravel with a custom filename?

Choose the code snippet that stores an uploaded file with a custom name preserving the original extension.

A

$file = $request->file('photo');
$filename = 'user_'.time().'.'.$file->extension();
$path = $file->storeAs('avatars', $filename);

B

$file = $request->file('photo');
$filename = 'user_'.time();
$path = $file->storeAs('avatars', $filename);

C

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

D

$file = $request->file('photo');
$filename = 'user_'.time().'.jpg';
$path = $file->store('avatars', $filename);

💡 Hint

Remember to preserve the original file extension and use the correct method to store with a custom name.

Option C uses getClientOriginalExtension() to get the original extension and storeAs to save with a custom filename.

🔧 Debug

advanced

Why does this Laravel file upload code throw an error?

Examine the code below. It throws an error when uploading a file. What is the cause?

Laravel

<?php
public function upload(Request $request) {
    $file = $request->file('document');
    $path = $file->store('uploads', 'public');
    return back()->with('message', 'Uploaded!');
}

A The code is missing a validation step, so Laravel blocks the upload.

B The 'public' disk is not configured in config/filesystems.php, causing a runtime error.

C The store method requires a filename, so this code throws a syntax error.

D The file variable is null because the input name is incorrect, causing a call on null error.

💡 Hint

Check if the file input name matches the request key.

If the input name in the form is not 'document', $request->file('document') returns null. Calling store on null causes an error.

❓ state_output

advanced

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

Given the code below, what will be the value of $filename if the uploaded file is named report.pdf?

Laravel

<?php
$file = $request->file('upload');
$filename = $file->hashName();

A A unique hashed string with the original extension, e.g., '3f1e2d4a5b6c7d8e9f0a.pdf'.

B The original filename 'report.pdf' without changes.

C A timestamp string like '1680000000.pdf'.

D An error because hashName requires a parameter.

💡 Hint

hashName generates a unique name with the original extension.

The hashName() method returns a unique filename using a hash and keeps the original file extension.

🧠 Conceptual

expert

Which Laravel feature ensures uploaded files are safely stored and accessible only as intended?

Among the options below, which Laravel feature best helps protect uploaded files from unauthorized access while allowing controlled retrieval?

A Using Laravel's Storage facade with private disks and generating temporary signed URLs for access.

B Saving files in the database as blobs to prevent direct file access.

C Storing files in the public directory and linking them directly via URL.

D Encrypting files manually before upload and decrypting on download.

💡 Hint

Think about Laravel's built-in tools for file storage and secure access.

Laravel's Storage facade supports private disks and temporary signed URLs, allowing files to be stored securely and accessed only with authorized links.