How can PHP developers efficiently validate file extensions before processing uploads?

To efficiently validate file extensions before processing uploads, PHP developers can use the pathinfo() function to extract the file extension from the uploaded file's name. They can then compare this extension against a list of allowed extensions to ensure only valid files are processed. 

$allowedExtensions = array('jpg', 'jpeg', 'png', 'gif');
$uploadedFile = $_FILES['file']['name'];
$extension = pathinfo($uploadedFile, PATHINFO_EXTENSION);

if (!in_array($extension, $allowedExtensions)) {
    // Handle invalid file extension error
    echo "Invalid file extension. Please upload a file with one of the following extensions: " . implode(', ', $allowedExtensions);
} else {
    // Process the uploaded file
}

Keywords

PHP file extension validation upload processing

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