Inspired by mod_cloudflare, this Elixir plug parses CloudFlare's CF-Connecting-IP HTTP request header into Plug.Conn's remote_ip field.

To use :plug_cloudflare in your projects, edit your mix.exs file and add :plug_cloudflare as a dependency:

defp deps do
  [
    {:plug_cloudflare, ">= 1.2.0"}
  ]
end

This plug should be one of the first ones in your pipeline. It is therefore recommended to put it in the endpoint instead of a pipeline.

defmodule MyApp.Endpoint do
  use Phoenix.Endpoint, otp_app: my_app
  plug Plug.CloudFlare
  # Other plugs omitted for clarity
end

This plug makes an effort to avoid tampering with the remote IP if the app is not running behind Cloudflare. The remote IP will only be changed by this plug if:

1. The CF-Connecting-IP header is present
2. The CF-Connecting-IP header parses to a valid IP address
3. The peer making the request is a Cloudflare IP address

This project uses the C4.1 process for all code changes.

"Everyone, without distinction or discrimination, SHALL have an equal right to become a Contributor under the terms of this contract."

Copyright (c) 2015 Constantin Rack

Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with the License. You may obtain a copy of the License at https://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the specific language governing permissions and limitations under the License.