84 lines
2.2 KiB
Elixir
84 lines
2.2 KiB
Elixir
# Pleroma: A lightweight social networking server
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# Copyright © 2017-2020 Pleroma Authors <https://pleroma.social/>
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# SPDX-License-Identifier: AGPL-3.0-only
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defmodule Pleroma.Web.Plugs.IdempotencyPlug do
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import Phoenix.Controller, only: [json: 2]
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import Plug.Conn
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@behaviour Plug
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@impl true
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def init(opts), do: opts
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# Sending idempotency keys in `GET` and `DELETE` requests has no effect
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# and should be avoided, as these requests are idempotent by definition.
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@impl true
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def call(%{method: method} = conn, _) when method in ["POST", "PUT", "PATCH"] do
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case get_req_header(conn, "idempotency-key") do
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[key] -> process_request(conn, key)
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_ -> conn
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end
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end
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def call(conn, _), do: conn
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def process_request(conn, key) do
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case Cachex.get(:idempotency_cache, key) do
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{:ok, nil} ->
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cache_resposnse(conn, key)
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{:ok, record} ->
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send_cached(conn, key, record)
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{atom, message} when atom in [:ignore, :error] ->
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render_error(conn, message)
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end
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end
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defp cache_resposnse(conn, key) do
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register_before_send(conn, fn conn ->
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[request_id] = get_resp_header(conn, "x-request-id")
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content_type = get_content_type(conn)
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record = {request_id, content_type, conn.status, conn.resp_body}
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{:ok, _} = Cachex.put(:idempotency_cache, key, record)
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conn
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|> put_resp_header("idempotency-key", key)
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|> put_resp_header("x-original-request-id", request_id)
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end)
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end
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defp send_cached(conn, key, record) do
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{request_id, content_type, status, body} = record
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conn
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|> put_resp_header("idempotency-key", key)
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|> put_resp_header("idempotent-replayed", "true")
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|> put_resp_header("x-original-request-id", request_id)
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|> put_resp_content_type(content_type)
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|> send_resp(status, body)
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|> halt()
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end
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defp render_error(conn, message) do
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conn
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|> put_status(:unprocessable_entity)
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|> json(%{error: message})
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|> halt()
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end
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defp get_content_type(conn) do
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[content_type] = get_resp_header(conn, "content-type")
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if String.contains?(content_type, ";") do
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content_type
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|> String.split(";")
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|> hd()
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else
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content_type
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end
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end
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end
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