137 lines
3.8 KiB
Elixir
137 lines
3.8 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.Plugs.Cache do
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@moduledoc """
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Caches successful GET responses.
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To enable the cache add the plug to a router pipeline or controller:
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plug(Pleroma.Plugs.Cache)
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## Configuration
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To configure the plug you need to pass settings as the second argument to the `plug/2` macro:
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plug(Pleroma.Plugs.Cache, [ttl: nil, query_params: true])
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Available options:
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- `ttl`: An expiration time (time-to-live). This value should be in milliseconds or `nil` to disable expiration. Defaults to `nil`.
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- `query_params`: Take URL query string into account (`true`), ignore it (`false`) or limit to specific params only (list). Defaults to `true`.
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- `tracking_fun`: A function that is called on successfull responses, no matter if the request is cached or not. It should accept a conn as the first argument and the value assigned to `tracking_fun_data` as the second.
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Additionally, you can overwrite the TTL inside a controller action by assigning `cache_ttl` to the connection struct:
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def index(conn, _params) do
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ttl = 60_000 # one minute
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conn
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|> assign(:cache_ttl, ttl)
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|> render("index.html")
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end
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"""
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import Phoenix.Controller, only: [current_path: 1, json: 2]
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import Plug.Conn
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@behaviour Plug
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@defaults %{ttl: nil, query_params: true}
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@impl true
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def init([]), do: @defaults
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def init(opts) do
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opts = Map.new(opts)
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Map.merge(@defaults, opts)
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end
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@impl true
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def call(%{method: "GET"} = conn, opts) do
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key = cache_key(conn, opts)
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case Cachex.get(:web_resp_cache, key) do
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{:ok, nil} ->
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cache_resp(conn, opts)
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{:ok, {content_type, body, tracking_fun_data}} ->
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conn = opts.tracking_fun.(conn, tracking_fun_data)
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send_cached(conn, {content_type, body})
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{:ok, record} ->
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send_cached(conn, 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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def call(conn, _), do: conn
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# full path including query params
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defp cache_key(conn, %{query_params: true}), do: current_path(conn)
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# request path without query params
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defp cache_key(conn, %{query_params: false}), do: conn.request_path
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# request path with specific query params
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defp cache_key(conn, %{query_params: query_params}) when is_list(query_params) do
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query_string =
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conn.params
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|> Map.take(query_params)
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|> URI.encode_query()
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conn.request_path <> "?" <> query_string
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end
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defp cache_resp(conn, opts) do
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register_before_send(conn, fn
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%{status: 200, resp_body: body} = conn ->
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ttl = Map.get(conn.assigns, :cache_ttl, opts.ttl)
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key = cache_key(conn, opts)
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content_type = content_type(conn)
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conn =
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unless opts[:tracking_fun] do
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Cachex.put(:web_resp_cache, key, {content_type, body}, ttl: ttl)
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conn
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else
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tracking_fun_data = Map.get(conn.assigns, :tracking_fun_data, nil)
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Cachex.put(:web_resp_cache, key, {content_type, body, tracking_fun_data}, ttl: ttl)
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opts.tracking_fun.(conn, tracking_fun_data)
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end
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put_resp_header(conn, "x-cache", "MISS from Pleroma")
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conn ->
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conn
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end)
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end
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defp content_type(conn) do
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conn
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|> Plug.Conn.get_resp_header("content-type")
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|> hd()
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end
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defp send_cached(conn, {content_type, body}) do
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conn
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|> put_resp_content_type(content_type, nil)
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|> put_resp_header("x-cache", "HIT from Pleroma")
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|> send_resp(:ok, 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(:internal_server_error)
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|> json(%{error: message})
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|> halt()
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end
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end
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