imap - PHP imap_fetchbody returns always false after reading empty mailbox/folder although mail is existing

I am familiar with PHP but quite new to IMAP processing. I try to read a mailbox for getting the body processed. This is working fine until the mailbox runs empty. After the first access to the empty INBOX (or even any folder or subfolder of the mailbox, I tried several settings), the imap_fetchbody() always returns false althought the box contains new mails again.

This is my code:

$imap = '{imap.strato.de:993/imap/ssl/novalidate-cert}INBOX';
$user = 'myuser';
$pass = 'mypassword';
$imapStream = imap_open($imap, $user, $pass);
$mailIds = imap_search($imapStream, 'ALL', SE_UID, 'ISO-8859-1');
foreach ($mailIds as $mailId) {

    $info = imap_mailboxmsginfo ( $imapStream );
    $body = imap_fetchbody ( $imapStream, $mailId, '1');
    if($body) {
        ... do something with the body ...
    }
    imap_delete($imapStream, $mailId, FT_UID);
}
imap_close($imapStream, CL_EXPUNGE);

Answer

Solution:

Could solve the Problem as follows:

This line gets all Mail-Ids from the Mailbox, cause of the flag=SE_UID):

$mailIds = imap_search($imapStream, 'ALL', SE_UID, 'ISO-8859-1');

But imap_fetchbody() wants to have a Mail-Number as default. Mail-Id and Mail-Number differ in most cases, so that imap_fetchbody() failed with the given Mail-Id, beacause this was a different int value as the expected Mail-Number.

Adding the Flag FT_UID in the following line solved the Problem:

imap_fetchbody($imapStream, $mailId, '1', FT_UID);

A typical IMAP newbie mistake? Never mind, I'm happy now :)

Source