77 lines
2.1 KiB
Elixir
77 lines
2.1 KiB
Elixir
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# Portions of this file are derived from Pleroma:
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# 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 Mobilizon.Service.RichMedia.Parsers.MetaTagsParser do
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@moduledoc """
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Module to parse meta tags data in HTML pages
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"""
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def parse(html, data, prefix, error_message, key_name, value_name \\ "content") do
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meta_data =
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html
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|> get_elements(key_name, prefix)
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|> Enum.reduce(data, fn el, acc ->
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attributes = normalize_attributes(el, prefix, key_name, value_name)
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Map.merge(acc, attributes)
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end)
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|> maybe_put_title(html)
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|> maybe_put_description(html)
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if Enum.empty?(meta_data) do
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{:error, error_message}
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else
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{:ok, meta_data}
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end
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end
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defp get_elements(html, key_name, prefix) do
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html |> Floki.find("meta[#{key_name}^='#{prefix}:']")
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end
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defp normalize_attributes(html_node, prefix, key_name, value_name) do
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{_tag, attributes, _children} = html_node
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data =
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Enum.into(attributes, %{}, fn {name, value} ->
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{name, String.trim_leading(value, "#{prefix}:")}
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end)
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%{String.to_atom(data[key_name]) => data[value_name]}
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end
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defp maybe_put_title(%{title: _} = meta, _), do: meta
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defp maybe_put_title(meta, html) when meta != %{} do
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case get_page_title(html) do
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"" -> meta
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title -> Map.put_new(meta, :title, title)
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end
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end
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defp maybe_put_title(meta, _), do: meta
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defp maybe_put_description(%{description: _} = meta, _), do: meta
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defp maybe_put_description(meta, html) when meta != %{} do
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case get_page_description(html) do
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"" -> meta
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description -> Map.put_new(meta, :description, description)
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end
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end
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defp maybe_put_description(meta, _), do: meta
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defp get_page_title(html) do
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html |> Floki.find("html head title") |> List.first() |> Floki.text()
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end
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defp get_page_description(html) do
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case html |> Floki.find("html head meta[name='description']") |> List.first() do
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nil -> ""
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elem -> Floki.attribute(elem, "content")
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end
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end
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end
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