Where should URIs be decoded in a Nginx - Puma - Rails stack?

Question

I've a Rails app that needs to accept some URIs with unencoded %2f (forward slashes). These characters need to be interpreted as forward slashes, even though I know it's not ideal.

What would be the best solution to do so? I'm thinking about a nginx rewrite rule or a custom rack middleware. Is there any other solution or suggested way to do so?

Answer 1

We ended up doing it with the following middleware:

class SlashDecoder
  def initialize(app)
    @app = app
  end

  def call(env)
    env["PATH_INFO"] = env["PATH_INFO"].gsub(/%2[fF]/, "/") if env["REQUEST_METHOD"] == "GET"
    @app.call(env)
  end
end