php - PHP で MIME タイプに関連付けられている拡張子を確認するにはどうすればよいですか?

Question

MIME タイプから PHP の拡張機能への簡単で汚いマッピングを利用できるものはありますか?

Answer 1

組み込みではありませんが、自分で作成するのはそれほど難しくありません。

function system_extension_mime_types() {
    # Returns the system MIME type mapping of extensions to MIME types, as defined in /etc/mime.types.
    $out = array();
    $file = fopen('/etc/mime.types', 'r');
    while(($line = fgets($file)) !== false) {
        $line = trim(preg_replace('/#.*/', '', $line));
        if(!$line)
            continue;
        $parts = preg_split('/\s+/', $line);
        if(count($parts) == 1)
            continue;
        $type = array_shift($parts);
        foreach($parts as $part)
            $out[$part] = $type;
    }
    fclose($file);
    return $out;
}

function system_extension_mime_type($file) {
    # Returns the system MIME type (as defined in /etc/mime.types) for the filename specified.
    #
    # $file - the filename to examine
    static $types;
    if(!isset($types))
        $types = system_extension_mime_types();
    $ext = pathinfo($file, PATHINFO_EXTENSION);
    if(!$ext)
        $ext = $file;
    $ext = strtolower($ext);
    return isset($types[$ext]) ? $types[$ext] : null;
}

function system_mime_type_extensions() {
    # Returns the system MIME type mapping of MIME types to extensions, as defined in /etc/mime.types (considering the first
    # extension listed to be canonical).
    $out = array();
    $file = fopen('/etc/mime.types', 'r');
    while(($line = fgets($file)) !== false) {
        $line = trim(preg_replace('/#.*/', '', $line));
        if(!$line)
            continue;
        $parts = preg_split('/\s+/', $line);
        if(count($parts) == 1)
            continue;
        $type = array_shift($parts);
        if(!isset($out[$type]))
            $out[$type] = array_shift($parts);
    }
    fclose($file);
    return $out;
}

function system_mime_type_extension($type) {
    # Returns the canonical file extension for the MIME type specified, as defined in /etc/mime.types (considering the first
    # extension listed to be canonical).
    #
    # $type - the MIME type
    static $exts;
    if(!isset($exts))
        $exts = system_mime_type_extensions();
    return isset($exts[$type]) ? $exts[$type] : null;
}