PHP File Uploads

Understanding PHP File Uploads

File uploads in PHP allow users to transfer files from their local machines to a server. This is commonly used in forms where users can upload documents, images, or other file types. PHP handles file uploads using the $_FILES superglobal array, which provides information about the uploaded file.

Setting Up a Basic File Upload Form

To start with file uploads, you need an HTML form with the attribute enctype="multipart/form-data". This is essential for file upload forms in PHP.

Processing the Uploaded File in PHP

Once the file is submitted, it is uploaded to a temporary location on the server. The PHP script upload.php will handle moving it to a permanent location and validating its size and type.

Validating File Size and Type

Validation is crucial in file uploads to prevent malicious files or excessively large files from being uploaded. The code example above demonstrates how to check the file size and restrict file types to common image formats (JPG, JPEG, PNG, and GIF).

Security Considerations

File uploads can be a security risk if not handled properly. Always validate file types and sizes, and store uploaded files in a designated directory outside of the web root. Consider using random filenames and directories to prevent direct access.