forked from YokaiRick/akkoma
142 lines
3.7 KiB
Elixir
142 lines
3.7 KiB
Elixir
# Pleroma: A lightweight social networking server
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# Copyright © 2017-2020 Pleroma Authors <https://pleroma.social/>
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# SPDX-License-Identifier: AGPL-3.0-only
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defmodule Pleroma.Web.RichMedia.Parser do
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require Logger
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defp parsers do
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Pleroma.Config.get([:rich_media, :parsers])
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end
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def parse(nil), do: {:error, "No URL provided"}
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if Pleroma.Config.get(:env) == :test do
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@spec parse(String.t()) :: {:ok, map()} | {:error, any()}
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def parse(url), do: parse_url(url)
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else
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@spec parse(String.t()) :: {:ok, map()} | {:error, any()}
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def parse(url) do
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with {:ok, data} <- get_cached_or_parse(url),
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{:ok, _} <- set_ttl_based_on_image(data, url) do
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{:ok, data}
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else
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{:error, {:invalid_metadata, data}} = e ->
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Logger.debug(fn -> "Incomplete or invalid metadata for #{url}: #{inspect(data)}" end)
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e
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error ->
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Logger.error(fn -> "Rich media error for #{url}: #{inspect(error)}" end)
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error
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end
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end
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defp get_cached_or_parse(url) do
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case Cachex.fetch!(:rich_media_cache, url, fn _ -> {:commit, parse_url(url)} end) do
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{:ok, _data} = res ->
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res
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{:error, :body_too_large} = e ->
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e
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{:error, {:content_type, _}} = e ->
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e
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# The TTL is not set for the errors above, since they are unlikely to change
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# with time
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{:error, _} = e ->
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ttl = Pleroma.Config.get([:rich_media, :failure_backoff], 60_000)
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Cachex.expire(:rich_media_cache, url, ttl)
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e
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end
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end
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end
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@doc """
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Set the rich media cache based on the expiration time of image.
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Adopt behaviour `Pleroma.Web.RichMedia.Parser.TTL`
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## Example
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defmodule MyModule do
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@behaviour Pleroma.Web.RichMedia.Parser.TTL
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def ttl(data, url) do
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image_url = Map.get(data, :image)
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# do some parsing in the url and get the ttl of the image
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# and return ttl is unix time
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parse_ttl_from_url(image_url)
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end
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end
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Define the module in the config
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config :pleroma, :rich_media,
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ttl_setters: [MyModule]
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"""
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@spec set_ttl_based_on_image(map(), String.t()) ::
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{:ok, Integer.t() | :noop} | {:error, :no_key}
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def set_ttl_based_on_image(data, url) do
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case get_ttl_from_image(data, url) do
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{:ok, ttl} when is_number(ttl) ->
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ttl = ttl * 1000
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case Cachex.expire_at(:rich_media_cache, url, ttl) do
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{:ok, true} -> {:ok, ttl}
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{:ok, false} -> {:error, :no_key}
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end
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_ ->
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{:ok, :noop}
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end
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end
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defp get_ttl_from_image(data, url) do
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[:rich_media, :ttl_setters]
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|> Pleroma.Config.get()
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|> Enum.reduce({:ok, nil}, fn
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module, {:ok, _ttl} ->
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module.ttl(data, url)
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_, error ->
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error
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end)
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end
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def parse_url(url) do
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with {:ok, %Tesla.Env{body: html}} <- Pleroma.Web.RichMedia.Helpers.rich_media_get(url),
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{:ok, html} <- Floki.parse_document(html) do
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html
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|> maybe_parse()
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|> Map.put("url", url)
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|> clean_parsed_data()
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|> check_parsed_data()
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end
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end
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defp maybe_parse(html) do
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Enum.reduce_while(parsers(), %{}, fn parser, acc ->
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case parser.parse(html, acc) do
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data when data != %{} -> {:halt, data}
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_ -> {:cont, acc}
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end
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end)
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end
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defp check_parsed_data(%{"title" => title} = data)
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when is_binary(title) and title != "" do
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{:ok, data}
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end
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defp check_parsed_data(data) do
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{:error, {:invalid_metadata, data}}
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end
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defp clean_parsed_data(data) do
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data
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|> Enum.reject(fn {key, val} ->
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not match?({:ok, _}, Jason.encode(%{key => val}))
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end)
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|> Map.new()
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end
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end
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