IMAP编码和解码：UTF-8问题

Question

I have a function which is meant to move a mail from one folder to another on a gmail account. The function is fully functional when it comes to moving the mail. Tho my problem appears when working with utf-8 encoded mailboxes. I decode the IMAP folder list response but the dump of both values gives different results.

// Getting the folders
$folders = imap_list(CONNECTION, MAILBOX, PATTERN);

// After a foreach, stripping slash, prefix and such
// $folder is the raw mailbox name from the IMAP list
$mailbox = utf8_encode(imap_utf7_decode($folder)); // = string(12) "Tæstbåks"

// The entered search from the client
$search_for = "Tæstbåks"; // = string(10) "Tæstbåks"

if($search_for == $mailbox)
    print "Yeah!";
else
    print "Noo!";

I do not know why those two strings do not match, that is my problem.

Answer 1

PHP's function imap_utf7_decode($folder) is documented to return a string in ISO-8859-1 encoding. Given that IMAP's modified UTF-7 scheme can encode the whole range of Unicode (which means "a lot") and that ISO-8859-1 can only represent 256 individual characters, you cannot possibly use that function in this context. I would go as far as to suggest that the PHP developer who decided to offer such a useless function was not in his best shape the day he designed it.

It looks like the mbstring extension can do what you really want to do here -- use something like $mailbox = mb_convert_encoding($folder, "UTF-8", "UTF7-IMAP") , as suggested in the comments below the PHP's docs.