Use constansts (#167)

* Use constansts

`MAILGUN_TRACK_CLICKS`
`MAILGUN_TRACK_OPENS`

for forcing settings on the backend

* Use constansts

`MAILGUN_TRACK_CLICKS`
`MAILGUN_TRACK_OPENS`

for forcing settings on the backend

includes/wp-mail-api.php

@@ -260,8 +260,18 @@ function wp_mail($to, $subject, $message, $headers = '', $attachments = [])
         }
 
         $body['o:tag'] = [];
-        $body['o:tracking-clicks'] = !empty($mailgun['track-clicks']) ? $mailgun['track-clicks'] : 'no';
-        $body['o:tracking-opens'] = empty($mailgun['track-opens']) ? 'no' : 'yes';
+        if (defined('MAILGUN_TRACK_CLICKS')) {
+            $trackClicks = MAILGUN_TRACK_CLICKS;
+        } else {
+            $trackClicks = !empty($mailgun['track-clicks']) ? $mailgun['track-clicks'] : 'no';
+        }
+        if (defined('MAILGUN_TRACK_OPENS')) {
+            $trackOpens = MAILGUN_TRACK_OPENS;
+        } else {
+            $trackOpens = empty($mailgun['track-opens']) ? 'no' : 'yes';
+        }
+        $body['o:tracking-clicks'] = $trackClicks;
+        $body['o:tracking-opens'] = $trackOpens;
 
         // this is the wordpress site tag
         if (isset($mailgun['tag'])) {

readme.md

@@ -66,6 +66,8 @@ MAILGUN_SECURE       Type: boolean  Choices: '0' or '1' (0 = false/no)
 MAILGUN_SECTYPE      Type: string   Choices: 'ssl' or 'tls'
 MAILGUN_FROM_NAME    Type: string
 MAILGUN_FROM_ADDRESS Type: string
+MAILGUN_TRACK_CLICKS Type: string Choices: 'yes' or 'no'
+MAILGUN_TRACK_OPENS  Type: string Choices: 'yes' or 'no'
 ```
 
 - What hooks are available for use with other plugins?

readme.txt

@@ -64,6 +64,8 @@ MAILGUN_SECURE       Type: boolean  Choices: '0' or '1' (0 = false/no)
 MAILGUN_SECTYPE      Type: string   Choices: 'ssl' or 'tls'
 MAILGUN_FROM_NAME    Type: string
 MAILGUN_FROM_ADDRESS Type: string
+MAILGUN_TRACK_CLICKS Type: string Choices: 'yes' or 'no'
+MAILGUN_TRACK_OPENS  Type: string Choices: 'yes' or 'no'
 `
 
 - What hooks are available for use with other plugins?