. # @param tag_name [String] name of the tag to parse # @param content [String] HTML content from which to parse a value # @return [String] if a value is successfully parsed # @return [nil] if the tag isn't present in content, or is not well-formed def self.parse_basic_tag(tag_name, content) open_tag = "<#{tag_name}" close_tag = "</#{tag_name}>" open_i = content.index open_tag return nil if open_i.nil? open_i = content.index('>', open_i + open_tag.size) + 1 close_i = content.index close_tag, open_i return nil if close_i.nil? content[open_i..close_i-1] end # Parses the (name, content) pairs from <meta> tags in the <head> element. # Note that it parses _only_ the `name` and `content` fields. # @param head_element [String] <head> element from an HTML document # @return [Hash<String, String>] a collection of (name, content) values def self.parse_meta_tags(head_element) open_tag = "<meta " open_i = head_element.index open_tag meta_tags = {} until open_i.nil? do # -1 to remove the space at the end. open_i += open_tag.size - 1 close_i = head_element.index '>', open_i return meta_tags if close_i.nil? current = head_element[open_i..close_i] attrs = {'name' => nil, 'content' => nil} attrs.keys.each do |attr| attr_begin = " #{attr}=" attr_begin_i = current.index attr_begin unless attr_begin_i.nil? attr_begin_i += attr_begin.size + 1 delim = current[attr_begin_i-1] attr_end_i = current.index delim, attr_begin_i next if attr_end_i.nil? attr_end_i -= 1 attrs[attr] = current[attr_begin_i..attr_end_i] end end meta_name = attrs['name'] meta_tags[meta_name] = attrs['content'] unless meta_name.nil? close_i += 1 open_i = head_element.index open_tag, close_i end meta_tags end # Parse actual content from an HTML page, leaving out boilerplate. # @param content [String] content of an HTML document # @param body_element_tag see {GeneratedSite#initialize} def self.parse_content_from_body(content, body_element_tag) body = parse_basic_tag 'body', content return content if body.nil? start_body = body.index body_element_tag unless body_element_tag.empty? return body if start_body.nil? start_body += 1 end_name_i = body.index ' ', start_body bracket_i = body.index '>', start_body end_name_i = bracket_i if bracket_i < end_name_i tag_name = body[start_body..end_name_i-1] open_tag = "<#{tag_name}" end_tag = "</#{tag_name}>" start_body = bracket_i + 1 search_i = start_body open_tag_i = body.index open_tag, search_i end_tag_i = body.index end_tag, search_i depth = 1 until depth == 0 if end_tag_i.nil? raise "End tag missing: #{end_tag}" end if !open_tag_i.nil? && open_tag_i < end_tag_i depth += 1 search_i = open_tag_i + open_tag.size open_tag_i = body.index open_tag, search_i else depth -= 1 search_i = end_tag_i + end_tag.size end_tag_i = body.index end_tag, search_i unless depth == 0 end end body[start_body..end_tag

# @author Mike Bland (michael.bland@gsa.gov) module JekyllPagesApi # Contains helper methods for parsing values from HTML. class GeneratedPageParser # Parses elements from a generated page's content needed by GeneratedPage. # @param content see {GeneratedPage#initialize} # @param title_prefix see {GeneratedSite#initialize} # @param body_element_tag see {GeneratedSite#initialize} # @return [Hash, String] the metadata hash containing the # `title`, `tags`, and `skip-index` elements; and the body content # stripped of boilerplate def self.parse_generated_page(content, title_prefix, body_element_tag) data = {} head_element = self.parse_basic_tag 'head', content return data, "" if head_element.nil? title = self.parse_basic_tag 'title', head_element if !title.nil? && title.start_with?(title_prefix) title = title[title_prefix.size..title.size] end data['title'] = title data.merge!(self.parse_meta_tags head_element) return data, self.parse_content_from_body(content, body_element_tag) end # Parses a value from content from between tags that cannot be nested, # e.g. , , . # @param tag_name [String] name of the tag to parse # @param content [String] HTML content from which to parse a value # @return [String] if a value is successfully parsed # @return [nil] if the tag isn't present in content, or is not well-formed def self.parse_basic_tag(tag_name, content) open_tag = "<#{tag_name}" close_tag = "</#{tag_name}>" open_i = content.index open_tag return nil if open_i.nil? open_i = content.index('>', open_i + open_tag.size) + 1 close_i = content.index close_tag, open_i return nil if close_i.nil? content[open_i..close_i-1] end # Parses the (name, content) pairs from <meta> tags in the <head> element. # Note that it parses _only_ the `name` and `content` fields. # @param head_element [String] <head> element from an HTML document # @return [Hash<String, String>] a collection of (name, content) values def self.parse_meta_tags(head_element) open_tag = "<meta " open_i = head_element.index open_tag meta_tags = {} until open_i.nil? do # -1 to remove the space at the end. open_i += open_tag.size - 1 close_i = head_element.index '>', open_i return meta_tags if close_i.nil? current = head_element[open_i..close_i] attrs = {'name' => nil, 'content' => nil} attrs.keys.each do |attr| attr_begin = " #{attr}=" attr_begin_i = current.index attr_begin unless attr_begin_i.nil? attr_begin_i += attr_begin.size + 1 delim = current[attr_begin_i-1] attr_end_i = current.index delim, attr_begin_i next if attr_end_i.nil? attr_end_i -= 1 attrs[attr] = current[attr_begin_i..attr_end_i] end end meta_name = attrs['name'] meta_tags[meta_name] = attrs['content'] unless meta_name.nil? close_i += 1 open_i = head_element.index open_tag, close_i end meta_tags end # Parse actual content from an HTML page, leaving out boilerplate. # @param content [String] content of an HTML document # @param body_element_tag see {GeneratedSite#initialize} def self.parse_content_from_body(content, body_element_tag) body = parse_basic_tag 'body', content return content if body.nil? start_body = body.index body_element_tag unless body_element_tag.empty? return body if start_body.nil? start_body += 1 end_name_i = body.index ' ', start_body bracket_i = body.index '>', start_body end_name_i = bracket_i if bracket_i < end_name_i tag_name = body[start_body..end_name_i-1] open_tag = "<#{tag_name}" end_tag = "</#{tag_name}>" start_body = bracket_i + 1 search_i = start_body open_tag_i = body.index open_tag, search_i end_tag_i = body.index end_tag, search_i depth = 1 until depth == 0 if end_tag_i.nil? raise "End tag missing: #{end_tag}" end if !open_tag_i.nil? && open_tag_i < end_tag_i depth += 1 search_i = open_tag_i + open_tag.size open_tag_i = body.index open_tag, search_i else depth -= 1 search_i = end_tag_i + end_tag.size end_tag_i = body.index end_tag, search_i unless depth == 0 end end body[start_body..end_tag_i-1] end end end