118 lines
3.1 KiB
Elixir
118 lines
3.1 KiB
Elixir
defmodule Readability.ArticleBuilder do
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@moduledoc """
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Build article for readability
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"""
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alias Readability.Helper
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alias Readability.Sanitizer
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alias Readability.Candidate
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alias Readability.CandidateFinder
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alias Readability.Candidate.Cleaner
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alias Readability.Candidate.Scoring
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@type html_tree :: tuple | list
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@type options :: list
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@doc """
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Prepare the article node for display.
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Clean out any inline styles, iframes, forms, strip extraneous <p> tags, etc.
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"""
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@spec build(html_tree, options) :: html_tree
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def build(html_tree, opts) do
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origin_tree = html_tree
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html_tree =
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html_tree
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|> Helper.remove_tag(fn {tag, _, _} ->
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Enum.member?(["script", "style"], tag)
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end)
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html_tree =
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if opts[:remove_unlikely_candidates],
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do: Cleaner.remove_unlikely_tree(html_tree),
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else: html_tree
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html_tree = Cleaner.transform_misused_div_to_p(html_tree)
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candidates = CandidateFinder.find(html_tree, opts)
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article = find_article(candidates, html_tree)
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html_tree = Sanitizer.sanitize(article, candidates, opts)
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if Helper.text_length(html_tree) < opts[:retry_length] do
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if opts = next_try_opts(opts) do
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build(origin_tree, opts)
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else
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html_tree
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end
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else
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html_tree
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end
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end
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defp next_try_opts(opts) do
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cond do
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opts[:remove_unlikely_candidates] ->
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Keyword.put(opts, :remove_unlikely_candidates, false)
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opts[:weight_classes] ->
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Keyword.put(opts, :weight_classes, false)
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opts[:clean_conditionally] ->
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Keyword.put(opts, :clean_conditionally, false)
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true ->
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nil
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end
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end
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defp find_article(candidates, html_tree) do
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best_candidate = CandidateFinder.find_best_candidate(candidates)
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article_trees =
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if best_candidate do
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find_article_trees(best_candidate, candidates)
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else
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fallback_candidate =
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case html_tree |> Floki.find("body") do
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[tree | _] -> %Candidate{html_tree: tree}
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_ -> %Candidate{html_tree: {}}
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end
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find_article_trees(fallback_candidate, candidates)
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end
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{"div", [], article_trees}
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end
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defp find_article_trees(best_candidate, candidates) do
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score_threshold = Enum.max([10, best_candidate.score * 0.2])
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candidates
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|> Enum.filter(&(&1.tree_depth == best_candidate.tree_depth))
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|> Enum.filter(fn candidate ->
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candidate == best_candidate || candidate.score >= score_threshold || append?(candidate)
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end)
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|> Enum.map(&to_article_tag(&1.html_tree))
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end
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defp append?(%Candidate{html_tree: html_tree}) when elem(html_tree, 0) == "p" do
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link_density = Scoring.calc_link_density(html_tree)
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inner_text = html_tree |> Floki.text()
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inner_length = inner_text |> String.length()
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(inner_length > 80 && link_density < 0.25) ||
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(inner_length < 80 && link_density == 0 && inner_text =~ ~r/\.( |$)/)
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end
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defp append?(_), do: false
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defp to_article_tag({tag, attrs, inner_tree} = html_tree) do
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if tag =~ ~r/^p$|^div$/ do
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html_tree
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else
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{"div", attrs, inner_tree}
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end
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end
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end
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