How to upload a big file from a form to Phoenix?

11
votes

I have an HTML form with a file field that is used to upload a file to a /file route in my Phoenix application.

I mimic this behaviour from command line with curl -v -F "file=@MyTestFile" http://localhost:4000/file/ for faster testing.

When I use a big file (turning point seems to be around 7.7MB), I get the following exception from Plug:

18:40:38.897 [error] Error in process <0.420.0> with exit value: {[{reason,#{'exception'=>true,'struct'=>'Elixir.Plug.Parsers.RequestTooLargeError',message=>nil}},{mfa,{'Elixir.Plug.Adapters.Cowboy.Handler',init,3}},{stacktrace,[{'Elixir.Plug.Parsers',reduce,6,[{file,"lib/plug...

Is there a workaround to allow bigger files to be uploaded?

There seems to be a :length option keyword in Plug, but how could I set it from Phoenix? And what is the reason this particular value of 8_000_000 has been chosen?

2
elixirphoenix-framework

2 Answers

6
votes

You can configure this in your config/config.exs file:

config :phoenix, MyApp.Router,
  ...
  parsers: [parsers: [:urlencoded, :multipart, :json],
            accept: ["*/*"],
            json_decoder: Poison,
            length: 100_000_000],
1
votes

FYI, for the most up-to-date docs on this functionality (since this question and these answers are pretty out-of-date at this point), see the official docs at: https://phoenixframework.readme.io/docs/file-uploads