Master PHP’s filetype() Function: Quickly Identify File Types

In PHP, the filetype() function is a built‑in utility for retrieving a file’s type, returning the type as a string or false on failure.

Function prototype: string filetype ( string $filename ) Parameter: $filename – the name or path of the file to examine.

Return value: Returns the file type as a string if successful; otherwise returns false.

Example 1: Get a file’s type

$filename = 'example.txt';
$filetype = filetype($filename);
if ($filetype !== false) {
    echo "File type: " . $filetype;
} else {
    echo "Failed to get file type!";
}

Example 2: Get types of all files in a directory

$dir = 'example_folder/';
$files = scandir($dir);
foreach ($files as $file) {
    if ($file != "." && $file != "..") {
        $filepath = $dir . $file;
        $filetype = filetype($filepath);
        if ($filetype !== false) {
            echo "File {$file} type: " . $filetype . "<br/>";
        } else {
            echo "Failed to get file type!";
        }
    }
}

The examples demonstrate using filetype() to obtain a file’s type and output it, first for a single file and then for each file in a directory using scandir() to list entries.

Conclusion

The filetype() function is a convenient tool that helps you identify file types, enabling you to handle different file formats appropriately, such as resizing images or processing text files.