Refactor Mobilizon.Federation.ActivityPub and add typespecs

Signed-off-by: Thomas Citharel <tcit@tcit.fr>

lib/web/media_proxy.ex

@@ -11,6 +11,7 @@ defmodule Mobilizon.Web.MediaProxy do
 
   @base64_opts [padding: false]
 
+  @spec url(String.t() | nil) :: String.t() | nil
   def url(url) when is_nil(url) or url == "", do: nil
   def url("/" <> _ = url), do: url
 
@@ -27,10 +28,12 @@ defmodule Mobilizon.Web.MediaProxy do
     not local?(url)
   end
 
+  @spec enabled? :: boolean()
   def enabled?, do: Config.get([:media_proxy, :enabled], false)
 
   def local?(url), do: String.starts_with?(url, Web.Endpoint.url())
 
+  @spec base64_sig64(String.t()) :: {String.t(), String.t()}
   defp base64_sig64(url) do
     base64 = Base.url_encode64(url, @base64_opts)
 
@@ -42,12 +45,14 @@ defmodule Mobilizon.Web.MediaProxy do
     {base64, sig64}
   end
 
+  @spec encode_url(String.t()) :: String.t()
   def encode_url(url) do
     {base64, sig64} = base64_sig64(url)
 
     build_url(sig64, base64, filename(url))
   end
 
+  @spec decode_url(String.t(), String.t()) :: {:ok, String.t()} | {:error, :invalid_signature}
   def decode_url(sig, url) do
     with {:ok, sig} <- Base.url_decode64(sig, @base64_opts),
          signature when signature == sig <- signed_url(url) do
@@ -57,10 +62,12 @@ defmodule Mobilizon.Web.MediaProxy do
     end
   end
 
+  @spec signed_url(String.t()) :: String.t()
   defp signed_url(url) do
     sha_hmac(Config.get([Web.Endpoint, :secret_key_base]), url)
   end
 
+  @spec sha_hmac(String.t(), String.t()) :: String.t()
   @compile {:no_warn_undefined, {:crypto, :mac, 4}}
   @compile {:no_warn_undefined, {:crypto, :hmac, 3}}
   defp sha_hmac(key, url) do
@@ -73,14 +80,17 @@ defmodule Mobilizon.Web.MediaProxy do
     end
   end
 
+  @spec filename(String.t()) :: String.t() | nil
   def filename(url_or_path) do
     if path = URI.parse(url_or_path).path, do: Path.basename(path)
   end
 
+  @spec base_url :: String.t()
   def base_url do
     Web.Endpoint.url()
   end
 
+  @spec proxy_url(String.t(), String.t(), String.t(), String.t() | nil) :: String.t()
   defp proxy_url(path, sig_base64, url_base64, filename) do
     [
       base_url(),
@@ -93,10 +103,13 @@ defmodule Mobilizon.Web.MediaProxy do
     |> Path.join()
   end
 
+  @spec build_url(String.t(), String.t(), String.t() | nil) :: String.t()
   def build_url(sig_base64, url_base64, filename \\ nil) do
     proxy_url("proxy", sig_base64, url_base64, filename)
   end
 
+  @spec verify_request_path_and_url(Plug.Conn.t() | String.t(), String.t()) ::
+          :ok | {:wrong_filename, String.t()}
   def verify_request_path_and_url(
         %Plug.Conn{params: %{"filename" => _}, request_path: request_path},
         url
@@ -116,6 +129,7 @@ defmodule Mobilizon.Web.MediaProxy do
 
   def verify_request_path_and_url(_, _), do: :ok
 
+  @spec basename_matches?(String.t(), String.t()) :: boolean()
   defp basename_matches?(path, filename) do
     basename = Path.basename(path)
     basename == filename or URI.decode(basename) == filename or URI.encode(basename) == filename