Merge pull request #3170 from llemoine/master

XOAUTH : Added support for long auth tokens

src/SMTP.php

@@ -633,10 +633,41 @@ class SMTP
                     return false;
                 }
                 $oauth = $OAuth->getOauth64();
-
+                /*
-                //Start authentication
+                 * An SMTP command line can have a maximum length of 512 bytes, including the command name,
-                if (!$this->sendCommand('AUTH', 'AUTH XOAUTH2 ' . $oauth, 235)) {
+                 * so the base64-encoded OAUTH token has a maximum length of:
-                    return false;
+                 * 512 - 13 (AUTH XOAUTH2) - 2 (CRLF) = 497 bytes
+                 * If the token is longer than that, the command and the token must be sent separately as described in
+                 * https://www.rfc-editor.org/rfc/rfc4954#section-4
+                 */
+                if ($oauth === '') {
+                    //Sending an empty auth token is legitimate, but it must be encoded as '='
+                    //to indicate it's not a 2-part command
+                    if (!$this->sendCommand('AUTH', 'AUTH XOAUTH2 =', 235)) {
+                        return false;
+                    }
+                } elseif (strlen($oauth) <= 497) {
+                    //Authenticate using a token in the initial-response part
+                    if (!$this->sendCommand('AUTH', 'AUTH XOAUTH2 ' . $oauth, 235)) {
+                        return false;
+                    }
+                } else {
+                    //The token is too long, so we need to send it in two parts.
+                    //Send the auth command without a token and expect a 334
+                    if (!$this->sendCommand('AUTH', 'AUTH XOAUTH2', 334)) {
+                        return false;
+                    }
+                    //Send the token
+                    if (!$this->sendCommand('OAuth TOKEN', $oauth, [235, 334])) {
+                        return false;
+                    }
+                    //If the server answers with 334, send an empty line and wait for a 235
+                    if (
+                        substr($this->last_reply, 0, 3) === '334'
+                        && $this->sendCommand('AUTH End', '', 235)
+                    ) {
+                        return false;
+                    }
                 }
                 break;
             default: