$_FILES for file uploads in PHP - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is the purpose of the $_FILES superglobal in PHP?

The $_FILES superglobal is used to collect information about files uploaded via an HTML form. It stores details like the file name, type, size, temporary location, and any upload errors.

beginner

Name the main keys inside the $_FILES['input_name'] array for an uploaded file.

• name: Original file name on the client machine
• type: MIME type of the file
• tmp_name: Temporary filename on the server
• error: Error code associated with the upload
• size: Size of the uploaded file in bytes

beginner

What does an error value of 0 mean in $_FILES['input_name']['error']?

An error value of 0 means the file uploaded successfully without any errors.

beginner

How do you access the temporary file path of an uploaded file named profile_pic?

You access it with $_FILES['profile_pic']['tmp_name']. This is the path where PHP stores the uploaded file temporarily before you move it.

beginner

Why should you use move_uploaded_file() after receiving a file via $_FILES?

Because the uploaded file is stored in a temporary location, move_uploaded_file() safely moves it to a permanent directory on your server. This prevents the file from being deleted after the script ends.

Which $_FILES key holds the original name of the uploaded file?

A tmp_name

B size

C name

D error

The name key contains the original filename from the user's computer.

What does $_FILES['file']['error'] === 4 indicate?

A File size exceeded limit

B No file was uploaded

C Partial upload

D Upload successful

Error code 4 means no file was uploaded.

Which PHP function should you use to move an uploaded file to a permanent location?

A move_uploaded_file()

B rename()

C copy()

D unlink()

move_uploaded_file() safely moves the uploaded file from the temporary folder.

Where does PHP store uploaded files before you move them?

A In the <code>$_POST</code> array

B In the <code>$_GET</code> array

C In the user's browser cache

D In a temporary folder on the server

Uploaded files are stored temporarily on the server in a temp folder.

What type of HTML form attribute is required to upload files?

A enctype="multipart/form-data"

B method="get"

C action="upload.php"

D target="_blank"

The form must have enctype="multipart/form-data" to upload files.

Explain how PHP's $_FILES array works when a user uploads a file through a form.

Think about the journey of the file from the user's computer to your server.

Describe the steps to safely handle a file upload in PHP using $_FILES.

Focus on safety and correctness when saving the uploaded file.