module Utils
module HtmlTransformer
SINGLE = 1
MULTIPLE = 2
COMMA_SEPARATED = 3
SRCSET = 4
URI_ATTRIBUTES = {
'a' => { 'href' => SINGLE },
'applet' => { 'archive' => COMMA_SEPARATED, 'codebase' => SINGLE },
'area' => { 'href' => SINGLE },
'audio' => { 'src' => SINGLE },
'base' => { 'href' => SINGLE },
'blockquote' => { 'cite' => SINGLE },
'body' => { 'background' => SINGLE },
'button' => { 'formaction' => SINGLE },
'command' => { 'icon' => SINGLE },
'del' => { 'cite' => SINGLE },
'embed' => { 'src' => SINGLE },
'form' => { 'action' => SINGLE },
'frame' => { 'longdesc' => SINGLE, 'src' => SINGLE },
'head' => { 'profile' => SINGLE },
'html' => { 'manifest' => SINGLE },
'iframe' => { 'longdesc' => SINGLE, 'src' => SINGLE },
'img' => { 'longdesc' => SINGLE, 'src' => SINGLE, 'srcset' => SRCSET, 'usemap' => SINGLE },
'input' => { 'formaction' => SINGLE, 'src' => SINGLE, 'usemap' => SINGLE },
'ins' => { 'cite' => SINGLE },
'link' => { 'href' => SINGLE },
'object' => { 'archive' => MULTIPLE, 'classid' => SINGLE, 'codebase' => SINGLE, 'data' => SINGLE, 'usemap' => SINGLE },
'q' => { 'cite' => SINGLE },
'script' => { 'src' => SINGLE },
'source' => { 'src' => SINGLE, 'srcset' => SRCSET },
'video' => { 'poster' => SINGLE, 'src' => SINGLE },
}
URI_ELEMENTS_XPATH = '//*[%s]' % URI_ATTRIBUTES.keys.map { |name| "name()='#{name}'" }.join(' or ')
module_function
def transform(html, &block)
block or raise ArgumentError, 'block must be given'
case html
when /\A\s*(?:<\?xml[\s?]|]/i
# Libxml2 automatically adds DOCTYPE and , so we need to
# skip them.
element_name = $1
doc = Nokogiri::HTML::Document.parse(html)
yield doc
doc.at_xpath("//#{element_name}").xpath('self::node() | following-sibling::node()').to_s
else
doc = Nokogiri::HTML::Document.parse("#{html}")
yield doc
doc.xpath("/html/body/node()").to_s
end
end
def replace_uris(html, &block)
block or raise ArgumentError, 'block must be given'
transform(html) { |doc|
doc.xpath(URI_ELEMENTS_XPATH).each { |element|
uri_attrs = URI_ATTRIBUTES[element.name] or next
uri_attrs.each { |name, format|
attr = element.attribute(name) or next
case format
when SINGLE
attr.value = block.call(attr.value.strip)
when MULTIPLE
attr.value = attr.value.gsub(/(\S+)/) { block.call($1) }
when COMMA_SEPARATED, SRCSET
attr.value = attr.value.gsub(/((?:\A|,)\s*)(\S+)/) { $1 + block.call($2) }
end
}
}
}
end
end
end