1 # Pleroma: A lightweight social networking server
2 # Copyright © 2017-2019 Pleroma Authors <https://pleroma.social/>
3 # SPDX-License-Identifier: AGPL-3.0-only
5 defmodule Pleroma.Web.MediaProxy do
6 @base64_opts [padding: false]
12 def url("/" <> _ = url), do: url
15 if !enabled?() or local?(url) or whitelisted?(url) do
22 defp enabled?, do: Pleroma.Config.get([:media_proxy, :enabled], false)
24 defp local?(url), do: String.starts_with?(url, Pleroma.Web.base_url())
26 defp whitelisted?(url) do
27 %{host: domain} = URI.parse(url)
29 Enum.any?(Pleroma.Config.get([:media_proxy, :whitelist]), fn pattern ->
30 String.equivalent?(domain, pattern)
34 def encode_url(url) do
35 secret = Pleroma.Config.get([Pleroma.Web.Endpoint, :secret_key_base])
37 # Must preserve `%2F` for compatibility with S3
38 # https://git.pleroma.social/pleroma/pleroma/issues/580
39 replacement = get_replacement(url, ":2F:")
41 # The URL is url-decoded and encoded again to ensure it is correctly encoded and not twice.
44 |> String.replace("%2F", replacement)
47 |> String.replace(replacement, "%2F")
48 |> Base.url_encode64(@base64_opts)
50 sig = :crypto.hmac(:sha, secret, base64)
51 sig64 = sig |> Base.url_encode64(@base64_opts)
53 build_url(sig64, base64, filename(url))
56 def decode_url(sig, url) do
57 secret = Pleroma.Config.get([Pleroma.Web.Endpoint, :secret_key_base])
58 sig = Base.url_decode64!(sig, @base64_opts)
59 local_sig = :crypto.hmac(:sha, secret, url)
61 if local_sig == sig do
62 {:ok, Base.url_decode64!(url, @base64_opts)}
64 {:error, :invalid_signature}
68 def filename(url_or_path) do
69 if path = URI.parse(url_or_path).path, do: Path.basename(path)
72 def build_url(sig_base64, url_base64, filename \\ nil) do
74 Pleroma.Config.get([:media_proxy, :base_url], Pleroma.Web.base_url()),
80 |> Enum.filter(fn value -> value end)
84 defp get_replacement(url, replacement) do
85 if String.contains?(url, replacement) do
86 get_replacement(url, replacement <> replacement)