# Pleroma: A lightweight social networking server # Copyright © 2017-2019 Pleroma Authors <https://pleroma.social/> # SPDX-License-Identifier: AGPL-3.0-only defmodule Pleroma.Web.RichMedia.Parser do @hackney_options [ pool: :media, recv_timeout: 2_000, max_body: 2_000_000, with_body: true ] defp parsers do Pleroma.Config.get([:rich_media, :parsers]) end def parse(nil), do: {:error, "No URL provided"} if Pleroma.Config.get(:env) == :test do def parse(url), do: parse_url(url) else def parse(url) do try 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)}"} end 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), ttl when is_number(ttl) <- get_ttl_from_image(data, url) do 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) html |> parse_html |> maybe_parse() |> Map.put(:url, url) |> clean_parsed_data() |> check_parsed_data() rescue e -> {:error, "Parsing error: #{inspect(e)}"} end end defp parse_html(html), do: Floki.parse(html) defp maybe_parse(html) do Enum.reduce_while(parsers(), %{}, fn parser, acc -> case parser.parse(html, acc) do {:ok, data} -> {:halt, data} {:error, _msg} -> {:cont, acc} end end) end defp check_parsed_data(%{title: title} = data) when is_binary(title) and byte_size(title) > 0 do {:ok, data} end defp check_parsed_data(data) do {:error, "Found metadata was invalid or incomplete: #{inspect(data)}"} end defp clean_parsed_data(data) do data |> Enum.reject(fn {key, val} -> with {:ok, _} <- Jason.encode(%{key => val}) do false else _ -> true end end) |> Map.new() end end