media proxy: good enough wip

lib/pleroma/web/media_proxy/controller.ex

@@ -0,0 +1,49 @@
+defmodule Pleroma.Web.MediaProxy.MediaProxyController do
+  use Pleroma.Web, :controller
+  require Logger
+
+  def remote(conn, %{"sig" => sig, "url" => url}) do
+    {:ok, url} = Pleroma.MediaProxy.decode_url(sig, url)
+    url = url |> URI.encode()
+    case proxy_request(url) do
+      {:ok, content_type, body} ->
+        conn
+        |> put_resp_content_type(content_type)
+        |> set_cache_header(:default)
+        |> send_resp(200, body)
+      other ->
+        conn
+        |> set_cache_header(:error)
+        |> redirect(external: url)
+    end
+  end
+
+  defp proxy_request(link) do
+    instance = )
+    headers = [{"user-agent", "Pleroma/MediaProxy; #{Pleroma.Web.base_url()} <#{Application.get_env(:pleroma, :instance)[:email]}>"}]
+    options = [:insecure, {:follow_redirect, true}]
+    case :hackney.request(:get, link, headers, "", options) do
+      {:ok, 200, headers, client} ->
+        headers = Enum.into(headers, Map.new)
+        {:ok, body} = :hackney.body(client)
+        {:ok, headers["Content-Type"], body}
+      {:ok, status, _, _} ->
+        Logger.warn "MediaProxy: request failed, status #{status}, link: #{link}"
+        {:error, :bad_status}
+      {:error, error} ->
+        Logger.warn "MediaProxy: request failed, error #{inspect error}, link: #{link}"
+        {:error, error}
+    end
+  end
+
+  @cache_control %{
+    default: "public, max-age=1209600",
+    error:   "public, must-revalidate, max-age=160",
+  }
+
+  defp set_cache_header(conn, true), do: set_cache_header(conn, :default)
+  defp set_cache_header(conn, false), do: set_cache_header(conn, :error)
+  defp set_cache_header(conn, key) when is_atom(key), do: set_cache_header(conn, @cache_control[key])
+  defp set_cache_header(conn, value) when is_binary(value), do: Plug.Conn.put_resp_header(conn, "cache-control", value)
+
+end

lib/pleroma/web/media_proxy/media_proxy.ex

@@ -0,0 +1,33 @@
+defmodule Pleroma.Web.MediaProxy do
+  @base64_opts [padding: false]
+  @base64_key Application.get_env(:pleroma, Pleroma.Web.Endpoint)[:secret_key_base]
+
+  def url(nil), do: nil
+
+  def url(url) do
+    if String.starts_with?(url, Pleroma.Web.base_url) do
+      url
+    else
+      base64 = Base.url_encode64(url, @base64_opts)
+      sig = :crypto.hmac(:sha, @base64_key, base64)
+      sig64 = sig |> Base.url_encode64(@base64_opts)
+      cache_url("#{sig64}/#{base64}")
+    end
+  end
+
+  def decode_url(sig, url) do
+    sig = Base.url_decode64!(sig, @base64_opts)
+    local_sig = :crypto.hmac(:sha, @base64_key, url)
+    if local_sig == sig do
+      {:ok, Base.url_decode64!(url, @base64_opts)}
+    else
+      {:error, :invalid_signature}
+    end
+  end
+
+  defp cache_url(path) do
+    "/proxy/" <> path
+  end
+
+
+end