Elixir arc delete file error

Questions / Help
1

Hey I am trying to delete files when the entity from the database is getting deleted following the example from the github page:

     {:ok, path} = ChallengeGroupAvatar.store({challenge_group.avatar, user})
     :ok = ChallengeGroupAvatar.delete({path, user})

but on the first line form these 2 I am getting this error:

no function clause matching in Arc.File.new/1

Why is that the case?
I even tried to do it with no scope, but the same error happens

2

Can you please provide the full stack trace?

3

this?

(exit) an exception was raised:
** (FunctionClauseError) no function clause matching in Arc.File.new/1
(arc) lib/arc/file.ex:16: Arc.File.new(%{file_name: “PICTURETEST.png”, updated_at: ~N[2018-10-24 16:15:58]})
(arc) lib/arc/actions/store.ex:9: Arc.Actions.Store.store/2
(userteam1) lib/userteam1_web/controllers/challenge_group_controller.ex:59: Userteam1Web.ChallengeGroupController.delete/2
(userteam1) lib/userteam1_web/controllers/challenge_group_controller.ex:1: Userteam1Web.ChallengeGroupController.action/2
(userteam1) lib/userteam1_web/controllers/challenge_group_controller.ex:1: Userteam1Web.ChallengeGroupController.phoenix_controller_pipeline/2
(userteam1) lib/userteam1_web/endpoint.ex:1: Userteam1Web.Endpoint.instrument/4
(phoenix) lib/phoenix/router.ex:278: Phoenix.Router.call/1
(userteam1) lib/userteam1_web/endpoint.ex:1: Userteam1Web.Endpoint.plug_builder_call/2
(userteam1) lib/plug/debugger.ex:122: Userteam1Web.Endpoint.“call (overridable 3)”/2
(userteam1) lib/userteam1_web/endpoint.ex:1: Userteam1Web.Endpoint.call/2
(plug) lib/plug/adapters/cowboy/handler.ex:16: Plug.Adapters.Cowboy.Handler.upgrade/4
(cowboy) /home/holo/Projects/userteamroleapi/deps/cowboy/src/cowboy_protocol.erl:442: :cowboy_protocol.execute/4

4

Arc.File.new/1 doesnt have any documentation, but if you look at the source here: https://github.com/stavro/arc/blob/master/lib/arc/file.ex#L27
Arc.File.new/1 accepts a binary, a map that looks like %{filename: filename, binary: binary} or a map that looks like %{filename: filename, path: path}, none of which match your input %{file_name: “PICTURETEST.png”, updated_at: ~N[2018-10-24 16:15:58]}

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5

Thanks,
so it seems like the scope is incorrect, so I checked in another place to get a link to the image and this wokrs there:

ChallengeGroupAvatar.url({challenge_group.avatar, challenge_group}, :original)

but i tried this way too and I am getting the same error

6

Your challenge_group.avatar or changed value in UserTeam1Web.Controllers.ChallengeGroupController.delete/2 (I don’t know your code) as in stacktrace contains map with file_name and updated_at keys. Both Arc.Actions.Store.store/2 and Arc.Actions.Url.url/2 requires to have valid parameter for Arc.File.new/1 which are one of:

  1. Remote url - i.e. binary which starts with http
  2. Local url - i.e. any other binary like /path/to/file.extension or relational file path like: ./path/to/file.extension
  3. Map which contains both of two keys: binary and filename
  4. Map which contains both of two keys: filename and path

This means that if you pass map or struct with:

  1. only one of those keys: binary, filename and path then it will fail
  2. all of those keys: binary, filename and path then path key would be ignored

I don’t know your code and structs, so I can’t say what you can pass, because from this part of error:

(arc) lib/arc/file.ex:16: Arc.File.new(%{file_name: “PICTURETEST.png”, updated_at: ~N[2018-10-24 16:15:58]})

I can see that you are passing only file_name and updated_at, so what you need to do is:

  1. Use file_name and pass it in remote url
    like: http://my.domain/path/to/#{challenge_group.avatar.file_name}

  2. Use file_name and pass it in local url
    like: /path/to/#{challenge_group.avatar.file_nam}
    or:   ./path/to/#{challenge_group.avatar.file_name}

  3. Use File.read/1 or File.read!/1 to get content of file and pass it in binary key, remove not needed updated_at key and change key file_name to filename

  4. Get path to file you are trying to reference with file_name, remove not needed updated_at key and change key file_name to filename

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