Class: JekyllPagesApi::GeneratedPageParser

Inherits:
Object
  • Object
show all
Defined in:
lib/jekyll_pages_api/generated_page_parser.rb

Overview

Contains helper methods for parsing values from HTML.

Class Method Summary collapse

Class Method Details

.parse_basic_tag(tag_name, content) ⇒ String?

Parses a value from content from between tags that cannot be nested, e.g. <head>, <body>, <title>.

Parameters:

  • tag_name (String) —

    name of the tag to parse

  • content (String) —

    HTML content from which to parse a value

Returns:

  • (String) —

    if a value is successfully parsed

  • (nil) —

    if the tag isn’t present in content, or is not well-formed



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# File 'lib/jekyll_pages_api/generated_page_parser.rb', line 33

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

.parse_content_from_body(content, body_element_tag) ⇒ Object

Parse actual content from an HTML page, leaving out boilerplate.

Parameters:



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# File 'lib/jekyll_pages_api/generated_page_parser.rb', line 85

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

.parse_generated_page(content, title_prefix, body_element_tag) ⇒ Hash<String, String>, String

Parses elements from a generated page’s content needed by GeneratedPage.

Parameters:

Returns:

  • (Hash<String, String>, String) —

    the metadata hash containing the ‘title`, `tags`, and `skip-index` elements; and the body content stripped of boilerplate



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# File 'lib/jekyll_pages_api/generated_page_parser.rb', line 13

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

.parse_meta_tags(head_element) ⇒ Hash<String, String>

Parses the (name, content) pairs from <meta> tags in the <head> element. Note that it parses only the ‘name` and `content` fields.

Parameters:

  • head_element (String) —

    <head> element from an HTML document

Returns:

  • (Hash<String, String>) —

    a collection of (name, content) values



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# File 'lib/jekyll_pages_api/generated_page_parser.rb', line 48

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