Only allow editing text files

app/controllers/tree_controller.rb

@@ -8,6 +8,7 @@ class TreeController < ProjectResourceController
   before_filter :require_non_empty_project
   before_filter :assign_ref_vars
+  before_filter :edit_requirements, only: [:edit, :update]
   def show
     @hex_path  = Digest::SHA1.hexdigest(@path)
@@ -40,4 +41,12 @@ class TreeController < ProjectResourceController
       render :edit
     end
   end
+
+  private
+
+  def edit_requirements
+    unless @tree.is_blob? && @tree.text?
+      redirect_to project_tree_path(@project, @id), notice: "You can only edit text files"
+    end
+  end
 end