fetcher: Fail Safely on Email Parse Error

This commit adds ability to log email parse errors. This can happen if the
system fails to fetch complete raw email or when the email content is malformed
somehow.

include/api.tickets.php

@@ -158,10 +158,14 @@ function createTicket($data) {
 
     function processEmail($data=false) {
 
-        if (!$data)
-            $data = $this->getEmailRequest();
-        elseif (!is_array($data))
-            $data = $this->parseEmail($data);
+        try {
+            if (!$data)
+                $data = $this->getEmailRequest();
+            elseif (!is_array($data))
+                $data = $this->parseEmail($data);
+        } catch (Exception $ex)  {
+            throw new EmailParseError($ex->getMessage());
+        }
 
         $seen = false;
         if (($entry = ThreadEntry::lookupByEmailHeaders($data, $seen))
@@ -246,7 +250,7 @@ static function process() {
     }
 }
 
-class TicketDenied extends Exception {
+class TicketDenied extends Exception {}
+class EmailParseError extends Exception {}
 
-}
 ?>

include/class.api.php

@@ -226,8 +226,10 @@ function parseRequest($stream, $format, $validate=true) {
                 return $this->exerr(415, __('Unsupported data format'));
         }
 
-        if (!($data = $parser->parse($stream)))
+        if (!($data = $parser->parse($stream))) {
             $this->exerr(400, $parser->lastError());
+            throw new Exception($parser->lastError());
+        }
 
         //Validate structure of the request.
         if ($validate && $data)

include/class.mailfetch.php

@@ -71,9 +71,15 @@ function createTicket(int $i) {
             // If a ticket is denied we're going to report it as processed
             // so it can be moved out of the inbox or deleted.
             return true;
+        } catch (\EmailParseError $ex) {
+            // Log the parse error + headers as a warning
+            $this->log(sprintf("%s\n\n%s",
+                        $ex->getMessage(),
+                        $this->mbox->getRawHeader($i)));
         } catch (\Throwable $t) {
-            return false;
+            //noop
         }
+        return false;
     }
 
     function processEmails() {