3 files changed, 100 insertions, 0 deletions
diff --git a/lib/pleroma/web/rich_media/parser.ex b/lib/pleroma/web/rich_media/parser.ex
index 0d2523338..b69b2be61 100644
--- a/lib/pleroma/web/rich_media/parser.ex
+++ b/lib/pleroma/web/rich_media/parser.ex
@@ -24,6 +24,7 @@ defmodule Pleroma.Web.RichMedia.Parser do
         Cachex.fetch!(:rich_media_cache, url, fn _ ->
           {:commit, parse_url(url)}
         end)
+        |> set_ttl_based_on_image(url)
       rescue
         e ->
           {:error, "Cachex error: #{inspect(e)}"}
@@ -31,6 +32,50 @@ defmodule Pleroma.Web.RichMedia.Parser do
     end
   end
 
+  @doc """
+  Set the rich media cache based on the expiration time of image.
+
+  Adopt behaviour `Pleroma.Web.RichMedia.Parser.TTL`
+
+  ## Example
+
+      defmodule MyModule do
+        @behaviour Pleroma.Web.RichMedia.Parser.TTL
+        def ttl(data, url) do
+          image_url = Map.get(data, :image)
+          # do some parsing in the url and get the ttl of the image
+          # and return ttl is unix time
+          parse_ttl_from_url(image_url)
+        end
+      end
+
+  Define the module in the config
+
+      config :pleroma, :rich_media,
+        ttl_setters: [MyModule]
+  """
+  def set_ttl_based_on_image({:ok, data}, url) do
+    with {:ok, nil} <- Cachex.ttl(:rich_media_cache, url) do
+      ttl = get_ttl_from_image(data, url)
+      Cachex.expire_at(:rich_media_cache, url, ttl * 1000)
+      {:ok, data}
+    else
+      _ ->
+        {:ok, data}
+    end
+  end
+
+  defp get_ttl_from_image(data, url) do
+    Pleroma.Config.get([:rich_media, :ttl_setters])
+    |> Enum.reduce({:ok, nil}, fn
+      module, {:ok, _ttl} ->
+        module.ttl(data, url)
+
+      _, error ->
+        error
+    end)
+  end
+
   defp parse_url(url) do
     try do
       {:ok, %Tesla.Env{body: html}} = Pleroma.HTTP.get(url, [], adapter: @hackney_options)
diff --git a/lib/pleroma/web/rich_media/parsers/ttl/aws_signed_url.ex b/lib/pleroma/web/rich_media/parsers/ttl/aws_signed_url.ex
new file mode 100644
index 000000000..014c0935f
--- /dev/null
+++ b/lib/pleroma/web/rich_media/parsers/ttl/aws_signed_url.ex
@@ -0,0 +1,52 @@
+defmodule Pleroma.Web.RichMedia.Parser.TTL.AwsSignedUrl do
+  @behaviour Pleroma.Web.RichMedia.Parser.TTL
+
+  @impl Pleroma.Web.RichMedia.Parser.TTL
+  def ttl(data, _url) do
+    image = Map.get(data, :image)
+
+    if is_aws_signed_url(image) do
+      image
+      |> parse_query_params()
+      |> format_query_params()
+      |> get_expiration_timestamp()
+    end
+  end
+
+  defp is_aws_signed_url(""), do: nil
+  defp is_aws_signed_url(nil), do: nil
+
+  defp is_aws_signed_url(image) when is_binary(image) do
+    %URI{host: host, query: query} = URI.parse(image)
+
+    if String.contains?(host, "amazonaws.com") and
+         String.contains?(query, "X-Amz-Expires") do
+      image
+    else
+      nil
+    end
+  end
+
+  defp is_aws_signed_url(_), do: nil
+
+  defp parse_query_params(image) do
+    %URI{query: query} = URI.parse(image)
+    query
+  end
+
+  defp format_query_params(query) do
+    query
+    |> String.split(~r/&|=/)
+    |> Enum.chunk_every(2)
+    |> Map.new(fn [k, v] -> {k, v} end)
+  end
+
+  defp get_expiration_timestamp(params) when is_map(params) do
+    {:ok, date} =
+      params
+      |> Map.get("X-Amz-Date")
+      |> Timex.parse("{ISO:Basic:Z}")
+
+    Timex.to_unix(date) + String.to_integer(Map.get(params, "X-Amz-Expires"))
+  end
+end
diff --git a/lib/pleroma/web/rich_media/parsers/ttl/ttl.ex b/lib/pleroma/web/rich_media/parsers/ttl/ttl.ex
new file mode 100644
index 000000000..6b3ec6d30
--- /dev/null
+++ b/lib/pleroma/web/rich_media/parsers/ttl/ttl.ex
@@ -0,0 +1,3 @@
+defmodule Pleroma.Web.RichMedia.Parser.TTL do
+  @callback ttl(Map.t(), String.t()) :: {:ok, Integer.t()} | {:error, String.t()}
+end