Image with $ sign in the name is broken in Enketo

[sadiqkhoja]

Related to #433

If image contains $ sign in the name then Enketo doesn't preview it.

[sadiqkhoja]

When I click on download icon on submission table, backend receives this request:

/v1/projects/473/forms/build_media_1556624635/submissions/uuid%3Abe2af264-615d-4658-afa5-385158ede558/attachments/%24dollar-8_45_1.jpg

However, URL in Enketo is /-/media/get/1/uuid:be2af264-615d-4658-afa5-385158ede558/%24dollar-8_45_1.jpg and it is not sending any request to backend.

[sadiqkhoja]

I initially thought it was Enketo's issue and create this PR.. However, it is nginx which is decoding %24 into $.

Experiments:

With following config, backend receives $ instead of %24

location /- {
      proxy_pass http://127.0.0.1:3000/-;
      proxy_redirect off;
      proxy_set_header Host $host;
    } 

If I remove /- from the proxy_pass then %24 is not decoded into $

the solution I came up with is

location /- {
      set $test http://127.0.0.1:3000/$request_uri;

      proxy_pass $test;
      proxy_redirect off;
      proxy_set_header Host $host;
    }

however, I don’t know the security implications of this.
https://trac.nginx.org/nginx/ticket/727 says that use $request_uri with care

I had opened an issue in Nginx issue tracker https://trac.nginx.org/nginx/ticket/2506. They say it is by design

[matthew-white]

However, it is nginx which is decoding %24 into $.

With following config, backend receives $ instead of %24

I'm pretty sure that Backend should be able to handle either $ or %24. Frontend calls encodeURIComponent(), which does encode $. Backend is happy to receive that encoded value, but it should also accept $ unencoded. For example, app user tokens in the URL can contain $, but we don't encode app user tokens in the URL. To test that Backend accepts $ unencoded, you can copy the download link from the submissions table and replace %24 with $. The link should still work.

However, URL in Enketo is /-/media/get/1/uuid:be2af264-615d-4658-afa5-385158ede558/%24dollar-8_45_1.jpg and it is not sending any request to backend.

If Enketo isn't sending a request at all, that still sounds like an Enketo issue to me. Do you happen to have a repro on a server handy? Are any requests to the Enketo server failing?