Class: Aws::AwsParser

Inherits:
Object show all
Defined in:
lib/awsbase/awsbase.rb

Overview

:nodoc:

Constant Summary collapse

DEFAULT_XML_LIBRARY =

default parsing library

'rexml'
@@supported_xml_libs =

a list of supported parsers

[DEFAULT_XML_LIBRARY, 'libxml']
@@xml_lib =

xml library name: ‘rexml’ | ‘libxml’

DEFAULT_XML_LIBRARY

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(params = {}) ⇒ AwsParser

Returns a new instance of AwsParser.



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# File 'lib/awsbase/awsbase.rb', line 641

def initialize(params={})
  @xmlpath = ''
  @result  = false
  @text    = ''
  @xml_lib = params[:xml_lib] || @@xml_lib
  @logger  = params[:logger]
  reset
end

Dynamic Method Handling

This class handles dynamic methods through the method_missing method

#method_missing(method, *params) ⇒ Object

Parser must have a lots of methods (see /usr/lib/ruby/1.8/rexml/parsers/streamparser.rb) We dont need most of them in AwsParser and method_missing helps us to skip their definition



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# File 'lib/awsbase/awsbase.rb', line 714

def method_missing(method, *params)
  # if the method is one of known - just skip it ...
  return if [:comment, :attlistdecl, :notationdecl, :elementdecl,
             :entitydecl, :cdata, :xmldecl, :attlistdecl, :instruction,
             :doctype].include?(method)
  # ... else - call super to raise an exception
  super(method, params)
end

Instance Attribute Details

#result ⇒ Object

Returns the value of attribute result.



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# File 'lib/awsbase/awsbase.rb', line 637

def result
  @result
end

#xml_lib ⇒ Object

Returns the value of attribute xml_lib.



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# File 'lib/awsbase/awsbase.rb', line 639

def xml_lib
  @xml_lib
end

#xmlpath ⇒ Object (readonly)

Returns the value of attribute xmlpath.



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# File 'lib/awsbase/awsbase.rb', line 638

def xmlpath
  @xmlpath
end

Class Method Details

.xml_lib ⇒ Object 



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# File 'lib/awsbase/awsbase.rb', line 630

def self.xml_lib
  @@xml_lib
end

.xml_lib=(new_lib_name) ⇒ Object 



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# File 'lib/awsbase/awsbase.rb', line 633

def self.xml_lib=(new_lib_name)
  @@xml_lib = new_lib_name
end

Instance Method Details

#parse(xml_text, params = {}) ⇒ Object

Parser method. Params:

xml_text         - xml message text(String) or Net:HTTPxxx instance (response)
params[:xml_lib] - library name: 'rexml' | 'libxml'



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# File 'lib/awsbase/awsbase.rb', line 668

def parse(xml_text, params={})
  # Get response body
  xml_text = xml_text.body unless xml_text.is_a?(String)
  @xml_lib = params[:xml_lib] || @xml_lib
  # check that we had no problems with this library otherwise use default
  @xml_lib = DEFAULT_XML_LIBRARY unless @@supported_xml_libs.include?(@xml_lib)
  # load xml library
  if @xml_lib=='libxml' && !defined?(XML::SaxParser)
    begin
      require 'xml/libxml'
      # is it new ? - Setup SaxParserCallback
      if XML::Parser::VERSION >= '0.5.1.0'
        SaxParserCallback.include_callback
      end
    rescue LoadError => e
      @@supported_xml_libs.delete(@xml_lib)
      @xml_lib = DEFAULT_XML_LIBRARY
      if @logger
        @logger.error e.inspect
        @logger.error e.backtrace
        @logger.info "Can not load 'libxml' library. '#{DEFAULT_XML_LIBRARY}' is used for parsing."
      end
    end
  end
  # Parse the xml text
  case @xml_lib
  when 'libxml'
    xml        = XML::SaxParser.new
    xml.string = xml_text
    # check libxml-ruby version
    if XML::Parser::VERSION >= '0.5.1.0'
      xml.callbacks = SaxParserCallback.new(self)
    else
      xml.on_start_element{|name, attr_hash| self.tag_start(name, attr_hash)}
      xml.on_characters{   |text|            self.text(text)}
      xml.on_end_element{  |name|            self.tag_end(name)}
    end
    xml.parse
  else
    REXML::Document.parse_stream(xml_text, self)
  end
end

#reset ⇒ Object

the functions to be overriden by children (if nessesery)



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# File 'lib/awsbase/awsbase.rb', line 723

def reset                     ; end

#tag_end(name) ⇒ Object 



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# File 'lib/awsbase/awsbase.rb', line 654

def tag_end(name)
  if @xmlpath =~ /^(.*?)\/?#{name}$/
    @xmlpath = $1
  end
  tagend(name)
end

#tag_start(name, attributes) ⇒ Object 



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# File 'lib/awsbase/awsbase.rb', line 649

def tag_start(name, attributes)
  @text = ''
  tagstart(name, attributes)
  @xmlpath += @xmlpath.empty? ? name : "/#{name}"
end

#tagend(name) ⇒ Object 



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# File 'lib/awsbase/awsbase.rb', line 725

def tagend(name)              ; end

#tagstart(name, attributes) ⇒ Object 



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# File 'lib/awsbase/awsbase.rb', line 724

def tagstart(name, attributes); end

#tagtext(text) ⇒ Object 



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# File 'lib/awsbase/awsbase.rb', line 726

def tagtext(text)             ; end

#text(text) ⇒ Object 



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# File 'lib/awsbase/awsbase.rb', line 660

def text(text)
  @text += text
  tagtext(text)
end