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|
# Pleroma: A lightweight social networking server
# Copyright © 2017-2020 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)} #{inspect(__STACKTRACE__)}"}
end
end
defp parse_html(html), do: Floki.parse_document!(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
|
