54 lines
1.5 KiB
Elixir
54 lines
1.5 KiB
Elixir
defmodule BackendWeb.RateLimiter do
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@moduledoc """
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Functions used to rate limit:
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* all endpoints by IP/endpoint
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* authentication endpoints by domain
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"""
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import Phoenix.Controller, only: [json: 2]
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import Plug.Conn, only: [put_status: 2]
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use Plug.Builder
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def rate_limit(conn, options \\ []) do
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case check_rate(conn, options) do
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{:ok, _count} -> conn # Do nothing, allow execution to continue
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{:error, _count} -> render_error(conn)
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end
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end
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def rate_limit_authentication(conn, options \\ []) do
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domain =
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if Map.has_key?(conn.params, "id") do
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Map.get(conn.params, "id")
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else
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Map.get(conn.params, "domain")
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end
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options = Keyword.put(options, :bucket_name, "authorization: #{domain}")
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rate_limit(conn, options)
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end
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defp check_rate(conn, options) do
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interval_milliseconds = options[:interval_seconds] * 1000
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max_requests = options[:max_requests]
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bucket_name = options[:bucket_name] || bucket_name(conn)
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ExRated.check_rate(bucket_name, interval_milliseconds, max_requests)
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end
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# Bucket name should be a combination of ip address and request path, like so:
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#
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# "127.0.0.1:/api/v1/authorizations"
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defp bucket_name(conn) do
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path = Enum.join(conn.path_info, "/")
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ip = conn.remote_ip |> Tuple.to_list |> Enum.join(".")
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"#{ip}:#{path}"
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end
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defp render_error(conn) do
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conn
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|> put_status(:forbidden)
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|> json(%{error: "Rate limit exceeded."})
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|> halt # Stop execution of further plugs, return response now
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end
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end
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