Add argument to fetch message parts only partially. Can be used for content mimetype detection without loading the entire file

program/lib/Roundcube/rcube_imap.php

@@ -2051,10 +2051,11 @@ class rcube_imap extends rcube_storage
      * @param  mixed              $print  True to print part, ressource to write part contents in
      * @param  resource           $fp     File pointer to save the message part
      * @param  boolean            $skip_charset_conv Disables charset conversion
+     * @param  int                $max_bytes  Only read this number of bytes
      *
      * @return string Message/part body if not printed
      */
-    public function get_message_part($uid, $part=1, $o_part=NULL, $print=NULL, $fp=NULL, $skip_charset_conv=false)
+    public function get_message_part($uid, $part=1, $o_part=NULL, $print=NULL, $fp=NULL, $skip_charset_conv=false, $max_bytes=0)
     {
         if (!$this->check_connection()) {
             return null;
@@ -2074,7 +2075,7 @@ class rcube_imap extends rcube_storage
 
         if ($o_part && $o_part->size) {
             $body = $this->conn->handlePartBody($this->folder, $uid, true,
-                $part ? $part : 'TEXT', $o_part->encoding, $print, $fp, $o_part->ctype_primary == 'text');
+                $part ? $part : 'TEXT', $o_part->encoding, $print, $fp, $o_part->ctype_primary == 'text', $max_bytes);
         }
 
         if ($fp || $print) {

program/lib/Roundcube/rcube_imap_generic.php

@@ -2379,7 +2379,7 @@ class rcube_imap_generic
         return $this->handlePartBody($mailbox, $id, $is_uid, $part);
     }
 
-    function handlePartBody($mailbox, $id, $is_uid=false, $part='', $encoding=NULL, $print=NULL, $file=NULL, $formatted=false)
+    function handlePartBody($mailbox, $id, $is_uid=false, $part='', $encoding=NULL, $print=NULL, $file=NULL, $formatted=false, $max_bytes=0)
     {
         if (!$this->select($mailbox)) {
             return false;
@@ -2405,10 +2405,11 @@ class rcube_imap_generic
         // Use BINARY extension when possible (and safe)
         $binary     = $mode && preg_match('/^[0-9.]+$/', $part) && $this->hasCapability('BINARY');
         $fetch_mode = $binary ? 'BINARY' : 'BODY';
+        $partial    = $max_bytes ? sprintf('<0.%d>', $max_bytes) : '';
 
         // format request
         $key       = $this->nextTag();
-        $request   = $key . ($is_uid ? ' UID' : '') . " FETCH $id ($fetch_mode.PEEK[$part])";
+        $request   = $key . ($is_uid ? ' UID' : '') . " FETCH $id ($fetch_mode.PEEK[$part]$partial)";
 
         // send request
         if (!$this->putLine($request)) {
@@ -2508,8 +2509,10 @@ class rcube_imap_generic
                     $line = rtrim($line, "\t\r\n\0\x0B") . "\n";
                 }
 
-                if ($file)
-                    fwrite($file, $line);
+                if ($file) {
+                    if (fwrite($file, $line) === false)
+                        break;
+                }
                 else if ($print)
                     echo $line;
                 else
@@ -2525,7 +2528,7 @@ class rcube_imap_generic
 
         if ($result !== false) {
             if ($file) {
-                fwrite($file, $result);
+                return fwrite($file, $result);
             } else if ($print) {
                 echo $result;
             } else

program/lib/Roundcube/rcube_message.php

@@ -173,10 +173,11 @@ class rcube_message
      * @param string   $mime_id           Part MIME-ID
      * @param resource $fp File           pointer to save the message part
      * @param boolean  $skip_charset_conv Disables charset conversion
+     * @param int      $max_bytes         Only read this number of bytes
      *
      * @return string Part content
      */
-    public function get_part_content($mime_id, $fp = null, $skip_charset_conv = false)
+    public function get_part_content($mime_id, $fp = null, $skip_charset_conv = false, $max_bytes = 0)
     {
         if ($part = $this->mime_parts[$mime_id]) {
             // stored in message structure (winmail/inline-uuencode)
@@ -190,7 +191,7 @@ class rcube_message
             // get from IMAP
             $this->storage->set_folder($this->folder);
 
-            return $this->storage->get_message_part($this->uid, $mime_id, $part, NULL, $fp, $skip_charset_conv);
+            return $this->storage->get_message_part($this->uid, $mime_id, $part, NULL, $fp, $skip_charset_conv, $max_bytes);
         }
     }