The imap_headerinfo() function in PHP

The PHP imap_headerinfo() function is used to get the header of an email message using the IMAP protocol.

The syntax of the function is as follows:

imap_headerinfo(
    IMAP\Connection $imap,
    int $message_num,
    int $from_length = 0,
    int $subject_length = 0
): stdClass|false

The function parameters are as follows:

$imap - object instance of the IMAP\Connection class (required)
$message_num - the message number you want to read the header from (required)
$from_length - the length of characters for the from property (optional)
$subject_length - the length of characters for the subject property (optional)

The function will return an object containing the header information. When there’s an error, it returns false.

To create an $imap object, you need to call the imap_open() function.

The code template for using the imap_headerinfo() is as follows:

<?php
// 👇 establish IMAP connection
$url = "{localhost:993/imap/ssl}INBOX";
$id = "[email protected]";
$pwd = "your email password";
$imap = imap_open($url, $id, $pwd);
print("Connection established. \n");

// 👇 fetching header info with imap_headerinfo()
print("Headers of all messages: \n");
$res = imap_headerinfo($imap, 1);	
print_r($res);

// 👇 close the IMAP connection
imap_close($imap);

When you successfully connected to the email server, you should see the header info printed on the screen.

An example of the header object is as follows:

stdClass Object (
[date] => Thu, 22 Aug 2022 20:10:52 +0000 
[message_id] => [toaddress] => ****@mail.com 
[to] => Array ( ... ) 
[fromaddress] => Sender [from] => Array ( ... ) 
[reply_toaddress] => Sender [reply_to] => Array ( ... ) 
[senderaddress] => Sender [sender] => Array ( ... ) 
[Recent] => [Unseen] => U [Flagged] => 
[Answered] => [Deleted] => [Draft] => [Msgno] => 2 
[MailDate] => 22-Aug-2022 20:10:52 +0000 
[Size] => 4858 [udate] => 1661173852 
)

Now you’ve learned how the imap_headerinfo() function works in PHP. Nice work! 👍

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