Class: HTMLTokenizer

Inherits:
Object
  • Object
show all
Defined in:
lib/openid/yadis/htmltokenizer.rb

Overview

A class to tokenize HTML.

Example:

page = "<HTML>
<HEAD>
<TITLE>This is the title</TITLE>
</HEAD>
 <!-- Here comes the <a href=\"missing.link\">blah</a>
 comment body
  -->
 <BODY>
   <H1>This is the header</H1>
   <P>
     This is the paragraph, it contains
     <a href=\"link.html\">links</a>,
     <img src=\"blah.gif\" optional alt='images
     are
     really cool'>.  Ok, here is some more text and
     <A href=\"http://another.link.com/\" target=\"_blank\">another link</A>.
   </P>
 </body>
 </HTML>
 "
 toke = HTMLTokenizer.new(page)

 assert("<h1>" == toke.getTag("h1", "h2", "h3").to_s.downcase)
 assert(HTMLTag.new("<a href=\"link.html\">") == toke.getTag("IMG", "A"))
 assert("links" == toke.getTrimmedText)
 assert(toke.getTag("IMG", "A").attr_hash['optional'])
 assert("_blank" == toke.getTag("IMG", "A").attr_hash['target'])

Constant Summary collapse

@@version = 
1.0

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(content) ⇒ HTMLTokenizer

Create a new tokenizer, based on the content, used as a string.



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# File 'lib/openid/yadis/htmltokenizer.rb', line 57

def initialize(content)
  @page = content.to_s
  @cur_pos = 0
end

Instance Attribute Details

#page ⇒ Object (readonly)

Returns the value of attribute page.



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# File 'lib/openid/yadis/htmltokenizer.rb', line 54

def page
  @page
end

Class Method Details

.version ⇒ Object

Get version of HTMLTokenizer lib



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# File 'lib/openid/yadis/htmltokenizer.rb', line 50

def self.version
  @@version
end

Instance Method Details

#getNextToken ⇒ Object

Get the next token, returns an instance of

  • HTMLText

  • HTMLToken

  • HTMLTag



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# File 'lib/openid/yadis/htmltokenizer.rb', line 101

def getNextToken
  token = peekNextToken
  if token
    # @page = @page[token.raw.length .. -1]
    # @page.slice!(0, token.raw.length)
    @cur_pos += token.raw.length
  end
  # p token
  # print token.raw
  token
end

#getTag(*sought_tags) ⇒ Object

Get a tag from the specified set of desired tags. For example: foo = toke.getTag("h1", "h2", "h3") Will return the next header tag encountered.



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# File 'lib/openid/yadis/htmltokenizer.rb', line 117

def getTag(*sought_tags)
  sought_tags.collect! { |elm| elm.downcase }

  while (tag = getNextToken)
    if tag.is_a?(HTMLTag) and
        (0 == sought_tags.length or sought_tags.include?(tag.tag_name))
      break
    end
  end
  tag
end

#getText(until_tag = nil) ⇒ Object

Get all the text between the current position and the next tag (if specified) or a specific later tag



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# File 'lib/openid/yadis/htmltokenizer.rb', line 131

def getText(until_tag = nil)
  if until_tag.nil?
    if "<" == @page[@cur_pos]
      # Next token is a tag, not text
      ""
    else
      # Next token is text
      getNextToken.text
    end
  else
    ret_str = ""

    while (tag = peekNextToken)
      break if tag.is_a?(HTMLTag) and tag.tag_name == until_tag

      ret_str << (tag.text + " ") if "" != tag.text
      getNextToken
    end

    ret_str
  end
end

#getTrimmedText(until_tag = nil) ⇒ Object

Like getText, but squeeze all whitespace, getting rid of leading and trailing whitespace, and squeezing multiple spaces into a single space.



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# File 'lib/openid/yadis/htmltokenizer.rb', line 157

def getTrimmedText(until_tag = nil)
  getText(until_tag).strip.gsub(/\s+/m, " ")
end

#peekNextToken ⇒ Object

Look at the next token, but don’t actually grab it



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# File 'lib/openid/yadis/htmltokenizer.rb', line 68

def peekNextToken
  return if @cur_pos == @page.length

  if "<" == @page[@cur_pos]
    # Next token is a tag of some kind
    if "!--" == @page[(@cur_pos + 1), 3]
      # Token is a comment
      tag_end = @page.index("-->", (@cur_pos + 1))
      raise HTMLTokenizerError, "No end found to started comment:\n#{@page[@cur_pos, 80]}" if tag_end.nil?

      # p @page[@cur_pos .. (tag_end+2)]
      HTMLComment.new(@page[@cur_pos..(tag_end + 2)])
    else
      # Token is a html tag
      tag_end = @page.index(">", (@cur_pos + 1))
      raise HTMLTokenizerError, "No end found to started tag:\n#{@page[@cur_pos, 80]}" if tag_end.nil?

      # p @page[@cur_pos .. tag_end]
      HTMLTag.new(@page[@cur_pos..tag_end])
    end
  else
    # Next token is text
    text_end = @page.index("<", @cur_pos)
    text_end = text_end.nil? ? -1 : (text_end - 1)
    # p @page[@cur_pos .. text_end]
    HTMLText.new(@page[@cur_pos..text_end])
  end
end

#reset ⇒ Object

Reset the parser, setting the current position back at the stop



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# File 'lib/openid/yadis/htmltokenizer.rb', line 63

def reset
  @cur_pos = 0
end