260 lines
7.3 KiB
Elixir
260 lines
7.3 KiB
Elixir
# Pleroma: A lightweight social networking server
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# Copyright © 2017-2019 Pleroma Authors <https://pleroma.social/>
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# SPDX-License-Identifier: AGPL-3.0-only
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defmodule Pleroma.HTML do
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alias HtmlSanitizeEx.Scrubber
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defp get_scrubbers(scrubber) when is_atom(scrubber), do: [scrubber]
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defp get_scrubbers(scrubbers) when is_list(scrubbers), do: scrubbers
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defp get_scrubbers(_), do: [Pleroma.HTML.Scrubber.Default]
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def get_scrubbers do
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Pleroma.Config.get([:markup, :scrub_policy])
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|> get_scrubbers
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end
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def filter_tags(html, nil) do
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filter_tags(html, get_scrubbers())
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end
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def filter_tags(html, scrubbers) when is_list(scrubbers) do
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Enum.reduce(scrubbers, html, fn scrubber, html ->
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filter_tags(html, scrubber)
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end)
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end
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def filter_tags(html, scrubber), do: Scrubber.scrub(html, scrubber)
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def filter_tags(html), do: filter_tags(html, nil)
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def strip_tags(html), do: Scrubber.scrub(html, Scrubber.StripTags)
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def get_cached_scrubbed_html_for_activity(content, scrubbers, activity, key \\ "") do
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key = "#{key}#{generate_scrubber_signature(scrubbers)}|#{activity.id}"
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Cachex.fetch!(:scrubber_cache, key, fn _key ->
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ensure_scrubbed_html(content, scrubbers, activity.data["object"]["fake"] || false)
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end)
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end
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def get_cached_stripped_html_for_activity(content, activity, key) do
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get_cached_scrubbed_html_for_activity(
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content,
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HtmlSanitizeEx.Scrubber.StripTags,
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activity,
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key
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)
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end
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def ensure_scrubbed_html(
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content,
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scrubbers,
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false = _fake
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) do
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{:commit, filter_tags(content, scrubbers)}
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end
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def ensure_scrubbed_html(
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content,
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scrubbers,
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true = _fake
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) do
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{:ignore, filter_tags(content, scrubbers)}
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end
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defp generate_scrubber_signature(scrubber) when is_atom(scrubber) do
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generate_scrubber_signature([scrubber])
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end
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defp generate_scrubber_signature(scrubbers) do
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Enum.reduce(scrubbers, "", fn scrubber, signature ->
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"#{signature}#{to_string(scrubber)}"
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end)
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end
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def extract_first_external_url(_, nil), do: {:error, "No content"}
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def extract_first_external_url(object, content) do
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key = "URL|#{object.id}"
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Cachex.fetch!(:scrubber_cache, key, fn _key ->
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result =
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content
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|> Floki.filter_out("a.mention")
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|> Floki.attribute("a", "href")
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|> Enum.at(0)
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{:commit, {:ok, result}}
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end)
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end
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end
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defmodule Pleroma.HTML.Scrubber.TwitterText do
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@moduledoc """
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An HTML scrubbing policy which limits to twitter-style text. Only
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paragraphs, breaks and links are allowed through the filter.
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"""
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@markup Application.get_env(:pleroma, :markup)
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@valid_schemes Pleroma.Config.get([:uri_schemes, :valid_schemes], [])
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require HtmlSanitizeEx.Scrubber.Meta
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alias HtmlSanitizeEx.Scrubber.Meta
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Meta.remove_cdata_sections_before_scrub()
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Meta.strip_comments()
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# links
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Meta.allow_tag_with_uri_attributes("a", ["href", "data-user", "data-tag"], @valid_schemes)
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Meta.allow_tag_with_these_attributes("a", ["name", "title", "class"])
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Meta.allow_tag_with_this_attribute_values("a", "rel", [
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"tag",
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"nofollow",
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"noopener",
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"noreferrer"
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])
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# paragraphs and linebreaks
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Meta.allow_tag_with_these_attributes("br", [])
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Meta.allow_tag_with_these_attributes("p", [])
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# microformats
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Meta.allow_tag_with_these_attributes("span", ["class"])
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# allow inline images for custom emoji
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@allow_inline_images Keyword.get(@markup, :allow_inline_images)
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if @allow_inline_images do
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# restrict img tags to http/https only, because of MediaProxy.
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Meta.allow_tag_with_uri_attributes("img", ["src"], ["http", "https"])
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Meta.allow_tag_with_these_attributes("img", [
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"width",
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"height",
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"title",
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"alt"
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])
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end
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Meta.strip_everything_not_covered()
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end
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defmodule Pleroma.HTML.Scrubber.Default do
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@doc "The default HTML scrubbing policy: no "
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require HtmlSanitizeEx.Scrubber.Meta
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alias HtmlSanitizeEx.Scrubber.Meta
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# credo:disable-for-previous-line
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# No idea how to fix this one…
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@markup Application.get_env(:pleroma, :markup)
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@valid_schemes Pleroma.Config.get([:uri_schemes, :valid_schemes], [])
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Meta.remove_cdata_sections_before_scrub()
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Meta.strip_comments()
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Meta.allow_tag_with_uri_attributes("a", ["href", "data-user", "data-tag"], @valid_schemes)
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Meta.allow_tag_with_these_attributes("a", ["name", "title", "class"])
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Meta.allow_tag_with_this_attribute_values("a", "rel", [
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"tag",
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"nofollow",
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"noopener",
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"noreferrer"
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])
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Meta.allow_tag_with_these_attributes("abbr", ["title"])
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Meta.allow_tag_with_these_attributes("b", [])
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Meta.allow_tag_with_these_attributes("blockquote", [])
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Meta.allow_tag_with_these_attributes("br", [])
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Meta.allow_tag_with_these_attributes("code", [])
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Meta.allow_tag_with_these_attributes("del", [])
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Meta.allow_tag_with_these_attributes("em", [])
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Meta.allow_tag_with_these_attributes("i", [])
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Meta.allow_tag_with_these_attributes("li", [])
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Meta.allow_tag_with_these_attributes("ol", [])
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Meta.allow_tag_with_these_attributes("p", [])
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Meta.allow_tag_with_these_attributes("pre", [])
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Meta.allow_tag_with_these_attributes("span", ["class"])
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Meta.allow_tag_with_these_attributes("strong", [])
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Meta.allow_tag_with_these_attributes("u", [])
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Meta.allow_tag_with_these_attributes("ul", [])
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@allow_inline_images Keyword.get(@markup, :allow_inline_images)
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if @allow_inline_images do
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# restrict img tags to http/https only, because of MediaProxy.
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Meta.allow_tag_with_uri_attributes("img", ["src"], ["http", "https"])
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Meta.allow_tag_with_these_attributes("img", [
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"width",
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"height",
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"title",
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"alt"
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])
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end
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@allow_tables Keyword.get(@markup, :allow_tables)
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if @allow_tables do
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Meta.allow_tag_with_these_attributes("table", [])
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Meta.allow_tag_with_these_attributes("tbody", [])
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Meta.allow_tag_with_these_attributes("td", [])
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Meta.allow_tag_with_these_attributes("th", [])
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Meta.allow_tag_with_these_attributes("thead", [])
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Meta.allow_tag_with_these_attributes("tr", [])
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end
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@allow_headings Keyword.get(@markup, :allow_headings)
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if @allow_headings do
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Meta.allow_tag_with_these_attributes("h1", [])
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Meta.allow_tag_with_these_attributes("h2", [])
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Meta.allow_tag_with_these_attributes("h3", [])
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Meta.allow_tag_with_these_attributes("h4", [])
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Meta.allow_tag_with_these_attributes("h5", [])
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end
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@allow_fonts Keyword.get(@markup, :allow_fonts)
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if @allow_fonts do
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Meta.allow_tag_with_these_attributes("font", ["face"])
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end
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Meta.strip_everything_not_covered()
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end
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defmodule Pleroma.HTML.Transform.MediaProxy do
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@moduledoc "Transforms inline image URIs to use MediaProxy."
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alias Pleroma.Web.MediaProxy
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def before_scrub(html), do: html
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def scrub_attribute("img", {"src", "http" <> target}) do
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media_url =
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("http" <> target)
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|> MediaProxy.url()
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{"src", media_url}
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end
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def scrub_attribute(_tag, attribute), do: attribute
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def scrub({"img", attributes, children}) do
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attributes =
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attributes
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|> Enum.map(fn attr -> scrub_attribute("img", attr) end)
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|> Enum.reject(&is_nil(&1))
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{"img", attributes, children}
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end
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def scrub({:comment, _children}), do: ""
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def scrub({tag, attributes, children}), do: {tag, attributes, children}
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def scrub({_tag, children}), do: children
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def scrub(text), do: text
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end
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