MM-9556 Added ability to upload files without a multipart request (#8306)

* MM-9556 Added ability to upload files without a multipart request

* MM-9556 Handled some unusual test behaviour

model/client4.go

@@ -1915,7 +1915,8 @@ func (c *Client4) DoPostAction(postId, actionId string) (bool, *Response) {
 
 // File Section
 
-// UploadFile will upload a file to a channel, to be later attached to a post.
+// UploadFile will upload a file to a channel using a multipart request, to be later attached to a post.
+// This method is functionally equivalent to Client4.UploadFileAsRequestBody.
 func (c *Client4) UploadFile(data []byte, channelId string, filename string) (*FileUploadResponse, *Response) {
 	body := &bytes.Buffer{}
 	writer := multipart.NewWriter(body)
@@ -1939,6 +1940,12 @@ func (c *Client4) UploadFile(data []byte, channelId string, filename string) (*F
 	return c.DoUploadFile(c.GetFilesRoute(), body.Bytes(), writer.FormDataContentType())
 }
 
+// UploadFileAsRequestBody will upload a file to a channel as the body of a request, to be later attached
+// to a post. This method is functionally equivalent to Client4.UploadFile.
+func (c *Client4) UploadFileAsRequestBody(data []byte, channelId string, filename string) (*FileUploadResponse, *Response) {
+	return c.DoUploadFile(c.GetFilesRoute()+fmt.Sprintf("?channel_id=%v&filename=%v", url.QueryEscape(channelId), url.QueryEscape(filename)), data, http.DetectContentType(data))
+}
+
 // GetFile gets the bytes for a file by id.
 func (c *Client4) GetFile(fileId string) ([]byte, *Response) {
 	if r, err := c.DoApiGet(c.GetFileRoute(fileId), ""); err != nil {