1 # Pleroma: A lightweight social networking server
2 # Copyright © 2017-2020 Pleroma Authors <https://pleroma.social/>
3 # SPDX-License-Identifier: AGPL-3.0-only
5 defmodule Pleroma.ReverseProxy do
6 @range_headers ~w(range if-range)
7 @keep_req_headers ~w(accept user-agent accept-encoding cache-control if-modified-since) ++
8 ~w(if-unmodified-since if-none-match) ++ @range_headers
9 @resp_cache_headers ~w(etag date last-modified)
10 @keep_resp_headers @resp_cache_headers ++
11 ~w(content-length content-type content-disposition content-encoding) ++
12 ~w(content-range accept-ranges vary)
13 @default_cache_control_header "public, max-age=1209600"
14 @valid_resp_codes [200, 206, 304]
15 @max_read_duration :timer.seconds(30)
16 @max_body_length :infinity
17 @failed_request_ttl :timer.seconds(60)
20 def max_read_duration_default, do: @max_read_duration
25 Pleroma.ReverseProxy.call(conn, url, options)
27 It is not meant to be added into a plug pipeline, but to be called from another plug or controller.
29 Supports `#{inspect(@methods)}` HTTP methods, and only allows `#{inspect(@valid_resp_codes)}` status codes.
31 Responses are chunked to the client while downloading from the upstream.
33 Some request / responses headers are preserved:
35 * request: `#{inspect(@keep_req_headers)}`
36 * response: `#{inspect(@keep_resp_headers)}`
40 * `redirect_on_failure` (default `false`). Redirects the client to the real remote URL if there's any HTTP
41 errors. Any error during body processing will not be redirected as the response is chunked. This may expose
42 remote URL, clients IPs, ….
44 * `max_body_length` (default `#{inspect(@max_body_length)}`): limits the content length to be approximately the
45 specified length. It is validated with the `content-length` header and also verified when proxying.
47 * `max_read_duration` (default `#{inspect(@max_read_duration)}` ms): the total time the connection is allowed to
48 read from the remote upstream.
50 * `failed_request_ttl` (default `#{inspect(@failed_request_ttl)}` ms): the time the failed request is cached and cannot be retried.
52 * `inline_content_types`:
53 * `true` will not alter `content-disposition` (up to the upstream),
54 * `false` will add `content-disposition: attachment` to any request,
55 * a list of whitelisted content types
57 * `keep_user_agent` will forward the client's user-agent to the upstream. This may be useful if the upstream is
58 doing content transformation (encoding, …) depending on the request.
60 * `req_headers`, `resp_headers` additional headers.
62 * `http`: options for [hackney](https://github.com/benoitc/hackney) or [gun](https://github.com/ninenines/gun).
65 @default_options [pool: :media]
67 @inline_content_types [
84 {:keep_user_agent, boolean}
85 | {:max_read_duration, :timer.time() | :infinity}
86 | {:max_body_length, non_neg_integer() | :infinity}
87 | {:failed_request_ttl, :timer.time() | :infinity}
89 | {:req_headers, [{String.t(), String.t()}]}
90 | {:resp_headers, [{String.t(), String.t()}]}
91 | {:inline_content_types, boolean() | [String.t()]}
92 | {:redirect_on_failure, boolean()}
94 @spec call(Plug.Conn.t(), url :: String.t(), [option()]) :: Plug.Conn.t()
95 def call(_conn, _url, _opts \\ [])
97 def call(conn = %{method: method}, url, opts) when method in @methods do
98 client_opts = Keyword.merge(@default_options, Keyword.get(opts, :http, []))
100 req_headers = build_req_headers(conn.req_headers, opts)
103 if filename = Pleroma.Web.MediaProxy.filename(url) do
104 Keyword.put_new(opts, :attachment_name, filename)
109 with {:ok, nil} <- Cachex.get(:failed_proxy_url_cache, url),
110 {:ok, code, headers, client} <- request(method, url, req_headers, client_opts),
112 header_length_constraint(
114 Keyword.get(opts, :max_body_length, @max_body_length)
116 response(conn, client, url, code, headers, opts)
120 |> error_or_redirect(url, 500, "Request failed", opts)
123 {:ok, code, headers} ->
124 head_response(conn, url, code, headers, opts)
127 {:error, {:invalid_http_response, code}} ->
128 Logger.error("#{__MODULE__}: request to #{inspect(url)} failed with HTTP status #{code}")
129 track_failed_url(url, code, opts)
132 |> error_or_redirect(
135 "Request failed: " <> Plug.Conn.Status.reason_phrase(code),
141 Logger.error("#{__MODULE__}: request to #{inspect(url)} failed: #{inspect(error)}")
142 track_failed_url(url, error, opts)
145 |> error_or_redirect(url, 500, "Request failed", opts)
150 def call(conn, _, _) do
152 |> send_resp(400, Plug.Conn.Status.reason_phrase(400))
156 defp request(method, url, headers, opts) do
157 Logger.debug("#{__MODULE__} #{method} #{url} #{inspect(headers)}")
158 method = method |> String.downcase() |> String.to_existing_atom()
160 case client().request(method, url, headers, "", opts) do
161 {:ok, code, headers, client} when code in @valid_resp_codes ->
162 {:ok, code, downcase_headers(headers), client}
164 {:ok, code, headers} when code in @valid_resp_codes ->
165 {:ok, code, downcase_headers(headers)}
168 {:error, {:invalid_http_response, code}}
175 defp response(conn, client, url, status, headers, opts) do
176 Logger.debug("#{__MODULE__} #{status} #{url} #{inspect(headers)}")
180 |> put_resp_headers(build_resp_headers(headers, opts))
181 |> send_chunked(status)
182 |> chunk_reply(client, opts)
188 {:error, :closed, conn} ->
189 client().close(client)
192 {:error, error, conn} ->
194 "#{__MODULE__} request to #{url} failed while reading/chunking: #{inspect(error)}"
197 client().close(client)
202 defp chunk_reply(conn, client, opts) do
203 chunk_reply(conn, client, opts, 0, 0)
206 defp chunk_reply(conn, client, opts, sent_so_far, duration) do
207 with {:ok, duration} <-
210 Keyword.get(opts, :max_read_duration, @max_read_duration)
212 {:ok, data, client} <- client().stream_body(client),
213 {:ok, duration} <- increase_read_duration(duration),
214 sent_so_far = sent_so_far + byte_size(data),
216 body_size_constraint(
218 Keyword.get(opts, :max_body_length, @max_body_length)
220 {:ok, conn} <- chunk(conn, data) do
221 chunk_reply(conn, client, opts, sent_so_far, duration)
224 {:error, error} -> {:error, error, conn}
228 defp head_response(conn, url, code, headers, opts) do
229 Logger.debug("#{__MODULE__} #{code} #{url} #{inspect(headers)}")
232 |> put_resp_headers(build_resp_headers(headers, opts))
233 |> send_resp(code, "")
236 defp error_or_redirect(conn, url, code, body, opts) do
237 if Keyword.get(opts, :redirect_on_failure, false) do
239 |> Phoenix.Controller.redirect(external: url)
243 |> send_resp(code, body)
248 defp downcase_headers(headers) do
249 Enum.map(headers, fn {k, v} ->
250 {String.downcase(k), v}
254 defp get_content_type(headers) do
256 List.keyfind(headers, "content-type", 0, {"content-type", "application/octet-stream"})
258 [content_type | _] = String.split(content_type, ";")
262 defp put_resp_headers(conn, headers) do
263 Enum.reduce(headers, conn, fn {k, v}, conn ->
264 put_resp_header(conn, k, v)
268 defp build_req_headers(headers, opts) do
270 |> downcase_headers()
271 |> Enum.filter(fn {k, _} -> k in @keep_req_headers end)
272 |> build_req_range_or_encoding_header(opts)
273 |> build_req_user_agent_header(opts)
274 |> Keyword.merge(Keyword.get(opts, :req_headers, []))
277 # Disable content-encoding if any @range_headers are requested (see #1823).
278 defp build_req_range_or_encoding_header(headers, _opts) do
279 range? = Enum.any?(headers, fn {header, _} -> Enum.member?(@range_headers, header) end)
281 if range? && List.keymember?(headers, "accept-encoding", 0) do
282 List.keydelete(headers, "accept-encoding", 0)
288 defp build_req_user_agent_header(headers, opts) do
289 if Keyword.get(opts, :keep_user_agent, false) do
294 {"user-agent", Pleroma.Application.user_agent()}
301 defp build_resp_headers(headers, opts) do
303 |> Enum.filter(fn {k, _} -> k in @keep_resp_headers end)
304 |> build_resp_cache_headers(opts)
305 |> build_resp_content_disposition_header(opts)
306 |> Keyword.merge(Keyword.get(opts, :resp_headers, []))
309 defp build_resp_cache_headers(headers, _opts) do
310 has_cache? = Enum.any?(headers, fn {k, _} -> k in @resp_cache_headers end)
314 # There's caching header present but no cache-control -- we need to set our own
315 # as Plug defaults to "max-age=0, private, must-revalidate"
320 {"cache-control", @default_cache_control_header}
328 {"cache-control", @default_cache_control_header}
333 defp build_resp_content_disposition_header(headers, opts) do
334 opt = Keyword.get(opts, :inline_content_types, @inline_content_types)
336 content_type = get_content_type(headers)
340 is_list(opt) && !Enum.member?(opt, content_type) -> true
348 {{"content-disposition", content_disposition_string}, _} =
349 List.keytake(headers, "content-disposition", 0)
353 ~r/filename="((?:[^"\\]|\\.)*)"/u,
354 content_disposition_string || "",
355 capture: :all_but_first
360 MatchError -> Keyword.get(opts, :attachment_name, "attachment")
363 disposition = "attachment; filename=\"#{name}\""
365 List.keystore(headers, "content-disposition", 0, {"content-disposition", disposition})
371 defp header_length_constraint(headers, limit) when is_integer(limit) and limit > 0 do
372 with {_, size} <- List.keyfind(headers, "content-length", 0),
373 {size, _} <- Integer.parse(size),
374 true <- size <= limit do
378 {:error, :body_too_large}
385 defp header_length_constraint(_, _), do: :ok
387 defp body_size_constraint(size, limit) when is_integer(limit) and limit > 0 and size >= limit do
388 {:error, :body_too_large}
391 defp body_size_constraint(_, _), do: :ok
393 defp check_read_duration(nil = _duration, max), do: check_read_duration(@max_read_duration, max)
395 defp check_read_duration(duration, max)
396 when is_integer(duration) and is_integer(max) and max > 0 do
398 {:error, :read_duration_exceeded}
400 {:ok, {duration, :erlang.system_time(:millisecond)}}
404 defp check_read_duration(_, _), do: {:ok, :no_duration_limit, :no_duration_limit}
406 defp increase_read_duration({previous_duration, started})
407 when is_integer(previous_duration) and is_integer(started) do
408 duration = :erlang.system_time(:millisecond) - started
409 {:ok, previous_duration + duration}
412 defp increase_read_duration(_) do
413 {:ok, :no_duration_limit, :no_duration_limit}
416 defp client, do: Pleroma.ReverseProxy.Client
418 defp track_failed_url(url, error, opts) do
420 unless error in [:body_too_large, 400, 204] do
421 Keyword.get(opts, :failed_request_ttl, @failed_request_ttl)
426 Cachex.put(:failed_proxy_url_cache, url, true, ttl: ttl)