Class: SandlebarsParser

Inherits:
Object show all
Defined in:
lib/volt/server/html_parser/sandlebars_parser.rb

Overview

This is not a full html parser, but should cover most common cases.

Constant Summary collapse

START_TAG =

regex matchers

/^<([-!\:A-Za-z0-9_]+)((?:\s+[\w\-]+(?:\s*=\s*(?:(?:"[^"]*")|(?:'[^']*')|[^>\s]+))?)*)\s*(\/?)>/
END_TAG = 
/^<\/([-!\:A-Za-z0-9_]+)[^>]*>/
ATTRIBUTES = 
/([-\:A-Za-z0-9_]+)(?:\s*=\s*(?:(?:"((?:\\.|[^"])*)")|(?:'((?:\\.|[^'])*)')|([^>\s]+)))?/
BLOCK =

Types of elements

truth_hash(%w{a address applet blockquote button center dd del dir div dl dt fieldset form frameset hr iframe ins isindex li map menu noframes noscript object ol p pre script table tbody td tfoot th thead tr ul})
EMPTY = 
truth_hash(%w{area base basefont br col frame hr img input isindex link meta param embed})
INLINE = 
truth_hash(%w{abbr acronym applet b basefont bdo big br button cite code del dfn em font i iframe img input ins kbd label map object q s samp script select small span strike strong sub sup textarea tt u var})
CLOSE_SELF = 
truth_hash(%w{colgroup dd dt li options p td tfoot th thead tr})
SPECIAL = 
truth_hash(%w{script style})
FILL_IN_ATTRIBUTES = 
truth_hash(%w{checked compact declare defer disabled ismap multiple nohref noresize noshade nowrap readonly selected})

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(html, handler, file_path = nil) ⇒ SandlebarsParser

Returns a new instance of SandlebarsParser.



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# File 'lib/volt/server/html_parser/sandlebars_parser.rb', line 34

def initialize(html, handler, file_path=nil)
  @html = StringScanner.new(html)
  @handler = handler
  @file_path = file_path

  @stack = []

  parse
end

Class Method Details

.truth_hash(array) ⇒ Object 



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# File 'lib/volt/server/html_parser/sandlebars_parser.rb', line 13

def self.truth_hash(array)
  hash = {}
  array.each {|v| hash[v] = true }

  return hash
end

Instance Method Details

#end_tag(tag, tag_name) ⇒ Object 



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# File 'lib/volt/server/html_parser/sandlebars_parser.rb', line 195

def end_tag(tag, tag_name)
  # If no tag name is provided, close all the way up
  new_size = 0

  if tag
    # Find the closest tag that closes.
    (@stack.size-1).downto(0) do |index|
      if @stack[index] == tag_name
        new_size = index
        break
      end
    end
  end

  if new_size >= 0
    if @handler.respond_to?(:end_tag)
      (@stack.size-1).downto(new_size) do |index|
        @handler.end_tag(@stack[index])
      end
    end

    @stack = @stack[0...new_size]
  end
end

#last ⇒ Object 



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# File 'lib/volt/server/html_parser/sandlebars_parser.rb', line 44

def last
  @stack.last
end

#parse ⇒ Object 



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# File 'lib/volt/server/html_parser/sandlebars_parser.rb', line 48

def parse
  loop do
    if last && SPECIAL[last]
      # In a script or style tag, just look for the first end
      close_tag = "</#{last}>"
      body = @html.scan_until(/#{close_tag}/)
      body = body[0..((-1 * close_tag.size)-1)]

      body = body.gsub(/\<\!--(.*?)--\>/, "\\1").gsub(/\<\!\[CDATA\[(.*?)\]\]\>/, "\\1")

      text(body)

      end_tag(last, last)
    elsif @html.scan(/\<\!--/)
      # start comment
      comment = @html.scan_until(/--\>/)
      comment = comment[0..-4]

      @handler.comment(comment) if @handler.respond_to?(:comment)
    elsif (tag = @html.scan(START_TAG))
      tag_name = @html[1]
      rest = @html[2]
      unary = @html[3]

      start_tag(tag, tag_name, rest, unary)
    elsif @html.scan(END_TAG)
      tag_name = @html[1]

      end_tag(tag_name, tag_name)
    elsif (escaped = @html.scan(/\{\{\{(.*?)\}\}\}([^\}]|$)/))
      # Anything between {{{ and }}} is escaped and not processed (treaded as text)
      if escaped[-1] != '}'
        # Move back if we matched a new non } for close, skip if we hit the end
        @html.pos = @html.pos - 1
      end

      text(@html[1])
    elsif (binding = @html.scan(/\{/))
      # We are in text mode and matched the start of a binding
      start_binding
    elsif (text = @html.scan(/(?:[^\<\{]+)/))
      # matched text up until the next html tag
      text(text)
    else
      # Nothing left
      break
    end
  end

  end_tag(nil, nil)
end

#raise_parse_error(error) ⇒ Object

Raises:



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# File 'lib/volt/server/html_parser/sandlebars_parser.rb', line 134

def raise_parse_error(error)
  line_number = @html.pre_match.count("\n") + 1

  error_str = error + " on line: #{line_number}"
  error_str += " of #{@file_path}" if @file_path

  raise HTMLParseError, error_str
end

#start_binding ⇒ Object

Findings the end of a binding



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# File 'lib/volt/server/html_parser/sandlebars_parser.rb', line 105

def start_binding
  binding = ''
  open_count = 1

  # scan until we reach a { or }
  loop do
    binding << @html.scan_until(/([\{\}\n]|\Z)/)

    match = @html[1]
    if match == '}'
      # close
      open_count -= 1
      break if open_count == 0
    elsif match == '{'
      # open more
      open_count += 1
    elsif match == "\n" || @html.eos?
      # Starting new tag, should be closed before this
      # or end of doc before closed binding
      raise_parse_error("unclosed binding: {#{binding.strip}")
    else
      raise "should not reach here"
    end
  end

  binding = binding[0..-2]
  @handler.binding(binding) if @handler.respond_to?(:binding)
end

#start_tag(tag, tag_name, rest, unary) ⇒ Object 



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# File 'lib/volt/server/html_parser/sandlebars_parser.rb', line 143

def start_tag(tag, tag_name, rest, unary)
  section_tag = tag_name[0] == ':' && tag_name[1] =~ /[A-Z]/

  tag_name = tag_name.downcase

  # handle doctype so we get it output exactly the same way
  if tag_name == '!doctype'
    @handler.text(tag) if @handler.respond_to?(:start_tag)
    return
  end

  # Auto-close the last inline tag if we started a new block
  if BLOCK[tag_name]
    if last && INLINE[last]
      end_tag(nil, last)
    end
  end

  # Some tags close themselves when a new one of themselves is reached.
  # ex, a tr will close the previous tr
  if CLOSE_SELF[tag_name] && last == tag_name
    end_tag(nil, tag_name)
  end

  unary = EMPTY[tag_name] || !unary.blank?

  # Section tag's are also unary
  unless unary || section_tag
    @stack.push(tag_name)
  end

  if @handler.respond_to?(:start_tag)
    attributes = {}

    # Take the rest string and extract the attributes, filling in any
    # "fill in" attribute values if not provided.
    rest.scan(ATTRIBUTES).each do |match|
      name = match[0]

      value = match[1] || match[2] || match[3] || FILL_IN_ATTRIBUTES[name] || ''

      attributes[name] = value
    end

    if section_tag
      @handler.start_section(tag_name, attributes, unary)
    else
      @handler.start_tag(tag_name, attributes, unary)
    end
  end
end

#text(text) ⇒ Object 



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# File 'lib/volt/server/html_parser/sandlebars_parser.rb', line 100

def text(text)
  @handler.text(text) if @handler.respond_to?(:text)
end