From e9982c521b187136fd197d11a1e5d9b022da5e38 Mon Sep 17 00:00:00 2001
From: href <href@random.sh>
Date: Fri, 30 Nov 2018 19:33:34 +0100
Subject: [PATCH] Upload filter: anonymize filename

It replaces the original filename with a randomly generated string.
---
 lib/pleroma/upload/filter/anonymize_filename.ex | 10 ++++++++++
 test/upload_test.exs                            | 14 ++++++++++++++
 2 files changed, 24 insertions(+)
 create mode 100644 lib/pleroma/upload/filter/anonymize_filename.ex

diff --git a/lib/pleroma/upload/filter/anonymize_filename.ex b/lib/pleroma/upload/filter/anonymize_filename.ex
new file mode 100644
index 000000000..a83e764e5
--- /dev/null
+++ b/lib/pleroma/upload/filter/anonymize_filename.ex
@@ -0,0 +1,10 @@
+defmodule Pleroma.Upload.Filter.AnonymizeFilename do
+  @moduledoc "Replaces the original filename with a randomly generated string."
+  @behaviour Pleroma.Upload.Filter
+
+  def filter(upload) do
+    extension = List.last(String.split(upload.name, "."))
+    string = Base.url_encode64(:crypto.strong_rand_bytes(10), padding: false)
+    {:ok, %Pleroma.Upload{upload | name: string <> "." <> extension}}
+  end
+end
diff --git a/test/upload_test.exs b/test/upload_test.exs
index cfd86ddd0..b2ce755d2 100644
--- a/test/upload_test.exs
+++ b/test/upload_test.exs
@@ -134,5 +134,19 @@ test "don't modify filename of an unknown type" do
       {:ok, data} = Upload.store(file)
       assert data["name"] == "test.txt"
     end
+
+    test "copies the file to the configured folder with anonymizing filename" do
+      File.cp!("test/fixtures/image.jpg", "test/fixtures/image_tmp.jpg")
+
+      file = %Plug.Upload{
+        content_type: "image/jpg",
+        path: Path.absname("test/fixtures/image_tmp.jpg"),
+        filename: "an [image.jpg"
+      }
+
+      {:ok, data} = Upload.store(file, filters: [Pleroma.Upload.Filter.AnonymizeFilename])
+
+      refute data["name"] == "an [image.jpg"
+    end
   end
 end