Roundcube multiple SMTP Server plugin for setups having multiple IMAP Server.

README.md

This plugin is not needed for versions >= 1.5 of roundcube, as the functionality was added by the developers!

Roundcube allows to access multiple IMAP Server, but all mails have to be send over the same SMTP server. This plugin allows to add multiple SMTP Server (one per IMAP Server) to Roundcube.

// normal declaration of multiple IMAP Server
$config['default_host'] = array(
		'ssl://imap.example.de' => '.de',
		'ssl://mx.example.com' => '.com'
	);

// normal SMTP declaration
$config['smtp_server'] = 'tls://smtp.example.de' // unable to add the SMTP Server for mx.example.com

// new SMTP declaration using the plugin
$config['smtp_server'] = array(
	'imap.example.de' => 'tls://smtp.example.de',
	'mx.example.com' => 'ssl://mx.example.de'
	// IMAP Hostname => SMTP Hostname
	//	(if IMAP Hostname is not in list, we use first SMTP Server)
);

//	and activate the plugin by adding to:
$config['plugins'] = array( ....., 'multi_smtp');

Install

Place the file multi_smtp.php in your installation at /plugins/multi_smtp/multi_smtp.php, edit the config.inc.php.

multi_smtp.php

<?php

class multi_smtp extends rcube_plugin {
	public $task = 'mail';
	
	function init(){
		if ( version_compare( RCMAIL_VERSION, '1.5', '<') ){ // plugin only needed until version 1.4.x
			$this->add_hook('smtp_connect', array($this, 'correct_smtp_server'));
		}
        }

	function correct_smtp_server( $data ){
		$imap_server = $_SESSION['storage_host'];
		$data['smtp_server'] = isset($data['smtp_server'][$imap_server]) ? $data['smtp_server'][$imap_server] : array_values($data['smtp_server'])[0];
		//print_r($data);
		return $data;
	}
}

?>

Hi,
I just took a look the error and I think this plugin is not needed any more, as the developers of roundcube added the functionality in roundcube itself starting with version 1.5.0 of roundcube (added here https://github.com/roundcube/roundcubemail/blob/1.5.0/program/lib/Roundcube/rcube_smtp.php#L60).

So just delete the folder plugins/multi_smtp and remove multi_smtp from $config['plugins'] if you are on version 1.5.0 or higher.

Hope this helps

@kimbtech thanks for this info.
I'm using 1.5.0
I've just tried and it works fine!