Added option to upload a file with custom name.

Author: Cerlin

README.md

@@ -60,7 +60,7 @@ So far this SDK has only machine to machine authentication mechanism and the fol
 2. Methods available in `$file_service`
 
         1. uploadPreFlight($file_path = "", $folder_id = 0);
-        2. upload($file_path = "", $folder_id = 0);
+        2. upload($file_path = "", $folder_id = 0, $filename = null); // If file name is null, filename will be derived from actual file name.
         3. getEmbedUrl($file_id)
         4. delete($file_id)
         5. destroyTrashedFile($file_id)

src/Box/Services/Files/FileService.php

@@ -74,15 +74,16 @@ private function readFile($file_path)
      * Method to upload the file. By default it uploads to the root folder which is id 0
      * @param string $file_path
      * @param int $folder_id
+     * @param string $filename
      * @return \GuzzleHttp\Psr7\Response
      */
-    public function upload($file_path = "", $folder_id = 0)
+    public function upload($file_path = "", $folder_id = 0, $filename = null)
     {
         Assert::integerish($folder_id, "The folder id must be an integer. Got: %s");
 
         $handle = $this->readFile($file_path);
 
-        $file_name = basename($file_path);
+        $filename = ((!is_null($filename)) ? $filename : basename($file_path));
 
         return $this->guzzle_client->request(
             'POST',
@@ -92,7 +93,7 @@ public function upload($file_path = "", $folder_id = 0)
                     [
                         "name" => "attributes",
                         "contents" => json_encode([
-                            "name" => $file_name,
+                            "name" => $filename,
                             "parent" => [
                                 "id" => $folder_id
                             ]