Font Awesome File Icons: Mapping MIME Types to correct icon classes

font-awesome-mime-type-icons.php

<?php

/**
* Get font awesome file icon class for specific MIME Type
* @see https://gist.github.com/guedressel/0daa170c0fde65ce5551
* @param string|null $mime_type
* @return string
*/
function font_awesome_file_icon_class(?string $mime_type): string
{
    // List of official MIME Types: http://www.iana.org/assignments/media-types/media-types.xhtml
    static $font_awesome_file_icon_classes = [
        // Images
        'image' => 'fa-file-image',
        // Audio
        'audio' => 'fa-file-audio',
        // Video
        'video' => 'fa-file-video',
        // Documents
        'application/pdf' => 'fa-file-pdf',
        'application/msword' => 'fa-file-word',
        'application/vnd.ms-word' => 'fa-file-word',
        'application/vnd.oasis.opendocument.text' => 'fa-file-word',
        'application/vnd.openxmlformats-officedocument.wordprocessingml' => 'fa-file-word',
        'application/vnd.ms-excel' => 'fa-file-excel',
        'application/vnd.openxmlformats-officedocument.spreadsheetml' => 'fa-file-excel',
        'application/vnd.oasis.opendocument.spreadsheet' => 'fa-file-excel',
        'application/vnd.ms-powerpoint' => 'fa-file-powerpoint',
        'application/vnd.openxmlformats-officedocument.presentationml' => 'ffa-file-powerpoint',
        'application/vnd.oasis.opendocument.presentation' => 'fa-file-powerpoint',
        'text/plain' => 'fa-file-alt',
        'text/html' => 'fa-file-code',
        'application/json' => 'fa-file-code',
        'application/vnd.openxmlformats-officedocument.wordprocessingml.document' => 'fa-file-word',
        'application/vnd.openxmlformats-officedocument.spreadsheetml.sheet' => 'fa-file-excel',
        'application/vnd.openxmlformats-officedocument.presentationml.presentation' => 'fa-file-powerpoint',
        // Archives
        'application/gzip' => 'fa-file-archive',
        'application/zip' => 'fa-file-archive',
        'application/x-zip-compressed' => 'fa-file-archive',
        // Misc
        'application/octet-stream' => 'fa-file-archive',
    ];

    return $font_awesome_file_icon_classes[$mime_type] ??
      $font_awesome_file_icon_classes[\substr($mime_type, 0, \strpos($mime_type, '/') ? : \strlen($mime_type))] ??
      'fa-file';
}

Updated to php >= 7.0 with type-hinting, null coalescing operator ?? and substr to retrieve value.