96 lines
2.4 KiB
Ruby
96 lines
2.4 KiB
Ruby
require 'html/pipeline/filter'
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require 'html/pipeline/sanitization_filter'
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module Banzai
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module Filter
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# Sanitize HTML
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#
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# Extends HTML::Pipeline::SanitizationFilter with a custom whitelist.
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class SanitizationFilter < HTML::Pipeline::SanitizationFilter
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def whitelist
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whitelist = super
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customize_whitelist(whitelist)
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whitelist
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end
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private
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def customized?(transformers)
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transformers.last.source_location[0] == __FILE__
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end
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def customize_whitelist(whitelist)
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# Only push these customizations once
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return if customized?(whitelist[:transformers])
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# Allow code highlighting
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whitelist[:attributes]['pre'] = %w(class)
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whitelist[:attributes]['span'] = %w(class)
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# Allow table alignment
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whitelist[:attributes]['th'] = %w(style)
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whitelist[:attributes]['td'] = %w(style)
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# Allow span elements
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whitelist[:elements].push('span')
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# Allow abbr elements with title attribute
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whitelist[:elements].push('abbr')
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whitelist[:attributes]['abbr'] = %w(title)
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# Allow any protocol in `a` elements...
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whitelist[:protocols].delete('a')
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# ...but then remove links with the `javascript` protocol
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whitelist[:transformers].push(remove_javascript_links)
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# Remove `rel` attribute from `a` elements
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whitelist[:transformers].push(remove_rel)
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# Remove `class` attribute from non-highlight spans
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whitelist[:transformers].push(clean_spans)
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whitelist
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end
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def remove_javascript_links
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lambda do |env|
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node = env[:node]
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return unless node.name == 'a'
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return unless node.has_attribute?('href')
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if node['href'].start_with?('javascript', ':javascript')
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node.remove_attribute('href')
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end
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end
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end
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def remove_rel
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lambda do |env|
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if env[:node_name] == 'a'
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env[:node].remove_attribute('rel')
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end
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end
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end
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def clean_spans
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lambda do |env|
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node = env[:node]
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return unless node.name == 'span'
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return unless node.has_attribute?('class')
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unless has_ancestor?(node, 'pre')
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node.remove_attribute('class')
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end
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{ node_whitelist: [node] }
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end
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end
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end
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end
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end
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