akkoma/lib/pleroma/web/rich_media/parser.ex

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# Pleroma: A lightweight social networking server
# Copyright © 2017-2019 Pleroma Authors <https://pleroma.social/>
# SPDX-License-Identifier: AGPL-3.0-only
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defmodule Pleroma.Web.RichMedia.Parser do
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@parsers [
Pleroma.Web.RichMedia.Parsers.OGP,
Pleroma.Web.RichMedia.Parsers.TwitterCard,
Pleroma.Web.RichMedia.Parsers.OEmbed
]
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def parse(nil), do: {:error, "No URL provided"}
if Mix.env() == :test do
def parse(url), do: parse_url(url)
else
def parse(url) do
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try do
Cachex.fetch!(:rich_media_cache, url, fn _ ->
{:commit, parse_url(url)}
end)
rescue
e ->
{:error, "Cachex error: #{inspect(e)}"}
end
end
end
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defp parse_url(url) do
try do
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{:ok, %Tesla.Env{body: html}} = Pleroma.HTTP.get(url, [], adapter: [pool: :media])
html |> maybe_parse() |> clean_parsed_data() |> check_parsed_data()
rescue
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e ->
{:error, "Parsing error: #{inspect(e)}"}
end
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end
defp maybe_parse(html) do
Enum.reduce_while(@parsers, %{}, fn parser, acc ->
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case parser.parse(html, acc) do
{:ok, data} -> {:halt, data}
{:error, _msg} -> {:cont, acc}
end
end)
end
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defp check_parsed_data(%{title: title} = data) when is_binary(title) and byte_size(title) > 0 do
{:ok, data}
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end
defp check_parsed_data(data) do
{:error, "Found metadata was invalid or incomplete: #{inspect(data)}"}
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end
defp string_is_valid_unicode(data) when is_binary(data) do
data
|> :unicode.characters_to_binary()
|> clean_string()
end
defp string_is_valid_unicode(data), do: {:ok, data}
defp clean_string({:error, _, _}), do: {:error, "Invalid data"}
defp clean_string(data), do: {:ok, data}
defp clean_parsed_data(data) do
data
|> Enum.reject(fn {_, val} ->
case string_is_valid_unicode(val) do
{:ok, _} -> false
_ -> true
end
end)
|> Map.new()
end
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end