How to accept gzipped requests in a rails 5 application?

Question

In the past I've used this solution, but since Rails 5 deprecated ParamsParser middleware, it doesn't work anymore.

Answer 1

Just add this:

# config/initializers/middlewares.rb
require 'compressed_requests'

Rails.application.configure do
  config.middleware.insert_before 0, CompressedRequests
end

Then add the middleware from this Gist to lib/middleware/compressed_requests.rb:

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

  def method_handled?(env)
    !!(env['REQUEST_METHOD'] =~ /(POST|PUT)/)
  end

  def encoding_handled?(env)
    ['gzip', 'deflate'].include? env['HTTP_CONTENT_ENCODING']
  end
  
  def call(env)
    if method_handled?(env) && encoding_handled?(env)
      extracted = decode(env['rack.input'], env['HTTP_CONTENT_ENCODING'])

      env.delete('HTTP_CONTENT_ENCODING')
      env['CONTENT_LENGTH'] = extracted.bytesize
      env['rack.input'] = StringIO.new(extracted)
    end

    @app.call(env)
  end
  
  def decode(input, content_encoding)
    case content_encoding
      when 'gzip' then Zlib::GzipReader.new(input).read
      when 'deflate' then Zlib::Inflate.inflate(input.read)
    end
  end
end

You can test it with:

# config/routes.rb
post '/', to: 'welcome#create'

# app/controllers/welcome_controller.rb
class WelcomeController < ActionController::Base
  def create
    render json: params
  end
end

And do the request:

$ curl --data-binary @<(echo "Uncompressed data" | gzip) \
  -H "CONTENT_ENCODING: gzip" \
  localhost:3000
{"Uncompressed data\n":null,"controller":"welcome","action":"create"}%