php error when trigger threshold sendmail

[yingbaiibm]

To Reproduce
Steps to reproduce the behavior:

1. Create multiple threshold and trigger them to sendmail to user
2. After trigger, check mail, only receive one mail.
3. Check Log, error exist and garbled log exist

2020/03/27 04:45:03 - CMDPHP MAILER ERROR Backtrace: (/poller.php[801]:api_plugin_hook(), /lib/plugins.php[74]:api_plugin_run_plugin_hook(), /lib/plugins.php[177]:thold_poller_bottom(), /plugins/thold/includes/polling.php[45]:thold_check_all_thresholds(), /plugins/thold/includes/polling.php[474]:thold_check_threshold(), /plugins/thold/thold_functions.php[2920]:thold_mail(), /plugins/thold/thold_functions.php[5388]:mailer(), /lib/functions.php[3535]:record_mailer_error(), /lib/functions.php[3733]:cacti_debug_backtrace())
2020/03/27 04:45:03 - CMDPHP MAILER ERROR:
2020/03/27 04:45:03 - CMDPHP MAILER ERROR Backtrace: (/poller.php[801]:api_plugin_hook(), /lib/plugins.php[74]:api_plugin_run_plugin_hook(), /lib/plugins.php[177]:thold_poller_bottom(), /plugins/thold/includes/polling.php[45]:thold_check_all_thresholds(), /plugins/thold/includes/polling.php[474]:thold_check_threshold(), /plugins/thold/thold_functions.php[2334]:thold_mail(), /plugins/thold/thold_functions.php[5388]:mailer(), /lib/functions.php[3535]:record_mailer_error(), /lib/functions.php[3733]:cacti_debug_backtrace())
2020/03/27 04:45:03 - CMDPHP MAILER ERROR:

At present, the main body of attachment specified by the mailer function provided by cacti core is PNG itself, but the third-party library phpmailer only supports the local file path. It recognizes the PNG content as a path and directly reports an error

Screenshots

Desktop (please complete the following information):
rhel8.2 x64
cacti 1.2.10
thold 1.3.4
FF 74

[ddb4github]

If mail body do not include both of <GRAPH> and <GRAPH:, functions.php--> mailer() will attach image object as attachement with PHPMailer-->addAttachment()
But PHPMailer-->addAttachment() only accept Local file path as attachment source.

[ddb4github]

How about this diff, then $attachment['attachment'] support both image realpath and image data..
Before this diff:

• mailer() will ignore attachment that is image data.
  After this diff:
• inline mode also support read attachment from local filepath

--- a/lib/functions.php
+++ b/lib/functions.php
@@ -3644,11 +3644,17 @@ function mailer($from, $to, $cc, $bcc, $replyto, $subject, $body, $body_text = '

                                /* attempt to attach */
                                if (!($graph_mode || $graph_ids)) {
-                                       if (!empty($attachment['filename']) && file_exists($attachment['filename'])) {
+                                       if (!empty($attachment['attachment']) && file_exists($attachment['attachment'])) {
                                                $result = $mail->addAttachment($attachment['attachment'], $attachment['filename'], $attachment['encoding'], $attachment['mime_type'], $attachment['inline']);
+                                       } else {
+                                               $result = $mail->addStringAttachment($attachment['attachment'], $attachment['filename'], 'base64', $attachment['mime_type'], $attachment['inline']);
                                        }
                                } else {
-                                       $result = $mail->addStringEmbeddedImage($attachment['attachment'], $cid, $attachment['filename'], 'base64', $attachment['mime_type'], $attachment['inline']);
+                                       if (!empty($attachment['attachment']) && file_exists($attachment['attachment'])) {
+                                               $result = $mail->addEmbeddedImage($attachment['attachment'], $cid, $attachment['filename'], 'base64', $attachment['encoding'], $attachment['mime_type'], $attachment['inline']);
+                                       } else {
+                                               $result = $mail->addStringEmbeddedImage($attachment['attachment'], $cid, $attachment['filename'], 'base64', $attachment['mime_type'], $attachment['inline']);
+                                       }
                                }

                                if ($result == false) {

[TheWitness]

It tried and received a number of back trace errors. Also, your theme pull request was reverted due to not working.

[ddb4github]

$result = $mail->addEmbeddedImage($attachment['attachment'], $cid, $attachment['filename'], 'base64', $attachment['encoding'], $attachment['mime_type'], $attachment['inline']);

should be

$result = $mail->addEmbeddedImage($attachment['attachment'], $cid, $attachment['filename'], $attachment['encoding'], $attachment['mime_type'], $attachment['inline']);

[TheWitness]

Just when I thought I could go for a walk.

[ddb4github]

Need to upgrade PHPMailer.
Before 6.1.0, function addStringAttachment does not return any true/false

[netniV]

If we have updated PHPMailer and that becomes a minimum requirement, packagers such as @paulgevers and @mortenstevens will need to add that to the requirements of their packages.

[netniV]

OK, I'm confused as both the commits listed in this issue are showing up as DEVELOP commits, yet appear it's @ddb4github's change that appears in the 1.2.x branch.