function drupal_mail_format_display_name

Return a RFC-2822 compliant "display-name" component.

The "display-name" component is used in mail header "Originator" fields (From, Sender, Reply-to) to give a human-friendly description of the address, i.e. From: My Display Name <xyz@example.org>. RFC-822 and RFC-2822 define its syntax and rules. This method gets as input a string to be used as "display-name" and formats it to be RFC compliant.

Parameters

string $string: A string to be used as "display-name".

Return value

string A RFC compliant version of the string, ready to be used as "display-name" in mail originator header fields.

File

includes/mail.inc, line 587

Code

function drupal_mail_format_display_name($string) {
    // Make sure we don't process html-encoded characters. They may create
    // unneeded trouble if left encoded, besides they will be correctly
    // processed if decoded.
    $string = decode_entities($string);
    // If string contains non-ASCII characters it must be (short) encoded
    // according to RFC-2047. The output of a "B" (Base64) encoded-word is
    // always safe to be used as display-name.
    $safe_display_name = mime_header_encode($string, TRUE);
    // Encoded-words are always safe to be used as display-name because don't
    // contain any RFC 2822 "specials" characters. However
    // mimeHeaderEncode() encodes a string only if it contains any
    // non-ASCII characters, and leaves its value untouched (un-encoded) if
    // ASCII only. For this reason in order to produce a valid display-name we
    // still need to make sure there are no "specials" characters left.
    if (preg_match('/[' . preg_quote(MAIL_RFC_2822_SPECIALS) . ']/', $safe_display_name)) {
        // If string is already quoted, it may or may not be escaped properly, so
        // don't trust it and reset.
        if (preg_match('/^"(.+)"$/', $safe_display_name, $matches)) {
            $safe_display_name = str_replace(array(
                '\\\\',
                '\\"',
            ), array(
                '\\',
                '"',
            ), $matches[1]);
        }
        // Transform the string in a RFC-2822 "quoted-string" by wrapping it in
        // double-quotes. Also make sure '"' and '\' occurrences are escaped.
        $safe_display_name = '"' . str_replace(array(
            '\\',
            '"',
        ), array(
            '\\\\',
            '\\"',
        ), $safe_display_name) . '"';
    }
    return $safe_display_name;
}