Webware for Python

Update of /cvsroot/webware/Webware/WebUtils
In directory usw-pr-cvs1:/tmp/cvs-serv10695/WebUtils

Modified Files:
	HTMLTag.py 
Log Message:
- added line numbers to html errors. this makes it easy to find errors
- added error checking for what tags can be inside what other tags
  new HTMLNotAllowedError is used for that
- allow HTMLTagErrors to have an arbitrary dictionary of values
  (that way you don't have to parse the information out of the message)


Index: HTMLTag.py
===================================================================
RCS file: /cvsroot/webware/Webware/WebUtils/HTMLTag.py,v
retrieving revision 1.6
retrieving revision 1.7
diff -C2 -d -r1.6 -r1.7
*** HTMLTag.py	21 Jul 2002 23:31:59 -0000	1.6
--- HTMLTag.py	15 Sep 2002 21:01:26 -0000	1.7
***************
*** 48,55 ****
  is broken for empty tags).
  
! * Determined what HTML tags are empty be scanning O'Reilly's HTML Pocket
  Reference.
  """
  
  
  # Check for Python 2.0
--- 48,59 ----
  is broken for empty tags).
  
! * Determined what HTML tags are empty by scanning O'Reilly's HTML Pocket
  Reference.
  """
  
+ # - report line numbers for errors
+ # - extra checking about what tags are allowed or disallowed inside other tags
+ # - minor tweaks
+ 
  
  # Check for Python 2.0
***************
*** 63,71 ****
  from MiscUtils import NoDefault
  import types
  
  
! class HTMLTagError(Exception): pass
! class HTMLTagAttrLookupError(LookupError, HTMLTagError): pass
  class HTMLTagUnbalancedError(HTMLTagError): pass
  class HTMLTagIncompleteError(HTMLTagError): pass
  
--- 67,83 ----
  from MiscUtils import NoDefault
  import types
+ from types import StringType
  
  
! class HTMLTagError(Exception):
! 
! 	def __init__(self, msg, **values):
! 		Exception.__init__(self, msg)
! 		self.values = values.copy()
! 
! class HTMLTagAttrLookupError(HTMLTagError, LookupError): pass
  class HTMLTagUnbalancedError(HTMLTagError): pass
+ class HTMLNotAllowedError(HTMLTagError): pass
+ class HTMLTagProcessingInstructionError(HTMLTagError): pass
  class HTMLTagIncompleteError(HTMLTagError): pass
  
***************
*** 235,239 ****
  		if tag is None:
  			if default is NoDefault:
! 				raise HTMLTagAttrLookupError, 'name = %r, value = %r' % (name, value)
  			else:
  				return default
--- 247,251 ----
  		if tag is None:
  			if default is NoDefault:
! 				raise HTMLTagAttrLookupError('name = %r, value = %r' % (name, value), name=name, value=value)
  			else:
  				return default
***************
*** 323,330 ****
  	* The reader is picky about the correctness of the HTML you feed it. If tags
  	  are not closed, overlap (instead of nest) or left unfinished, an exception is
! 	  thrown. These include HTMLTagUnbalancedError and HTMLTagIncompleteError both of
! 	  which inherit HTMLTagError. I believe it is possible that others kinds of HTML
! 	  errors could raise exceptions from sgmlib.SGMLParser (from which HTMLReader
! 	  inherits).
  
  
--- 335,347 ----
  	* The reader is picky about the correctness of the HTML you feed it. If tags
  	  are not closed, overlap (instead of nest) or left unfinished, an exception is
! 	  thrown. These include HTMLTagUnbalancedError, HTMLTagIncompleteError and
! 	  HTMLNotAllowedError which all inherit HTMLTagError.
! 
! 	  This pickiness can be quite useful for the validation of the HTML of your
! 	  own applications.
! 
! 	  I believe it is possible that others kinds of HTML errors could raise
! 	  exceptions from sgmlib.SGMLParser (from which HTMLReader inherits),
! 	  although in practice, I have not seen them.
  
  
***************
*** 336,339 ****
--- 353,359 ----
  
  	* Readers don't handle processing instructions: <? foobar ?>.
+ 
+ 	* The tagContainmentConfig class var can certainly be expanded for even better
+ 	  validation.
  	"""
  
***************
*** 384,389 ****
  		self._finished = 0
  		self.reset()
  		try:
! 			self.feed(string)
  			self.close()
  		finally:
--- 404,413 ----
  		self._finished = 0
  		self.reset()
+ 		self._lineNumber = 1
+ 		self.computeTagContainmentConfig()
  		try:
! 			for line in string.split('\n'):
! 				self.feed(line+'\n')
! 				self._lineNumber += 1
  			self.close()
  		finally:
***************
*** 497,501 ****
  
  	def handle_pi(self, data):
! 		raise Exception, 'Was not expecting a processing instruction: %r' % data
  
  	def unknown_starttag(self, name, attrs):
--- 521,525 ----
  
  	def handle_pi(self, data):
! 		raise HTMLTagProcessingInstructionError, 'Was not expecting a processing instruction: %r' % data
  
  	def unknown_starttag(self, name, attrs):
***************
*** 515,520 ****
  			# If it's the first tag and it isn't an <html> tag,
  			# create a fake "container" html tag.
! 			if self._rootTag:
! 				self._tagStack[-1].addChild(tag)
  			elif name != 'html' and self._fakeRootTagIfNeeded:
  				self._rootTag = HTMLTag('html')
--- 539,550 ----
  			# If it's the first tag and it isn't an <html> tag,
  			# create a fake "container" html tag.
! 			if self._tagStack:
! 				lastTag = self._tagStack[-1]
! 				# is this legal?
! 				tagConfig = self._tagContainmentConfig.get(lastTag.name())
! 				if tagConfig:
! 					tagConfig.encounteredTag(name, self._lineNumber)
! 				# tell last tag about his new child
! 				lastTag.addChild(tag)
  			elif name != 'html' and self._fakeRootTagIfNeeded:
  				self._rootTag = HTMLTag('html')
***************
*** 539,548 ****
  			print 'END   %s: %r' % (name.ljust(6), self._tagStack)
  		if openingTag.name()!=name:
! 			raise HTMLTagUnbalancedError, 'Opening is %r, but closing is %r' % \
! 				(openingTag.name(), name)
  
  	def close(self):
  		if len(self._tagStack)>0 and not (len(self._tagStack)==1 and self._usedFakeRootTag):
! 			raise HTMLTagIncompleteError, 'tagStack = %r' % self._tagStack
  		SGMLParser.close(self)
  
--- 569,578 ----
  			print 'END   %s: %r' % (name.ljust(6), self._tagStack)
  		if openingTag.name()!=name:
! 			raise HTMLTagUnbalancedError('line %i: opening is %r, but closing is %r' % \
! 				(self._lineNumber, openingTag.name(), name), line=self._lineNumber, opening=openingTag.name(), closing=name)
  
  	def close(self):
  		if len(self._tagStack)>0 and not (len(self._tagStack)==1 and self._usedFakeRootTag):
! 			raise HTMLTagIncompleteError('line %i: tagStack = %r' % (self._lineNumber, self._tagStack), line=line, tagStack=repr(self._tagStack))
  		SGMLParser.close(self)
  
***************
*** 559,562 ****
--- 589,657 ----
  			dict[tag] = 1
  		self._emptyTagDict = dict
+ 
+ 	# The following dict defines for various tags either:
+ 	#    + the complete set of tags that can be contained within
+ 	#    - a set of tags that cannot be contained within
+ 	# This information helps HTMLReader detect some types of errors
+ 	# earlier and other types of errors, it would never detect.
+ 	tagContainmentConfig = {
+ 		'html':   'canOnlyHave head body',
+ 		'head':   'cannotHave  html head body',
+ 		'body':   'cannotHave  html head body',
+ 		'table':  'canOnlyHave th tr tbody a',  # a because in IE you can wrap a row in <a> to make the entire row clickable
+ 		'tr':     'canOnlyHave td',
+ 		'td':     'cannotHave  td tr',
+ 		'select': 'canOnlyHave option',
+ 	}
+ 
+ 	def computeTagContainmentConfig(self):
+ 		config = {}
+ 		for key, value in self.tagContainmentConfig.items():
+ 			if isinstance(value, StringType):
+ 				value = value.split()
+ 				configClass = configClassForName.get(value[0])
+ 				if configClass is None:
+ 					raise KeyError, 'Unknown config name %r for value %r in %s.tagContainmentConfig' % (key, value, self.__class__.__name__)
+ 				config[key] = configClass(key, value[1:])
+ 			else:
+ 				assert isinstance(value, TagConfig), 'key=%r, value=%r' % (key, value)
+ 				config[key] = value
+ 		self._tagContainmentConfig = config
+ 
+ 
+ class TagConfig:
+ 
+ 	def __init__(self, name, tags):
+ 		self.name = name
+ 		# turn list of tags into a dict/set for fast lookup (e.g., avoid linear searches)
+ 		dict = {}
+ 		for tag in tags:
+ 			dict[tag] = 1
+ 		self.tags = dict
+ 
+ 	def encounteredTag(self, tag, lineNum):
+ 		raise SubclassResponsiblityError, self.__class__
+ 
+ 
+ class TagCanOnlyHaveConfig(TagConfig):
+ 
+ 	def encounteredTag(self, tag, lineNum):
+ 		if not self.tags.has_key(tag.lower()):
+ 			raise HTMLNotAllowedError('line %i: the tag %r is not allowed in %r which can only have %r.' % (
+ 				lineNum, tag, self.name, self.tags.keys()), line=lineNum, encounteredTag=tag, containingTag=self.name, canOnlyHave=self.tags.keys())
+ 
+ 
+ class TagCannotHaveConfig(TagConfig):
+ 
+ 	def encounteredTag(self, tag, lineNum):
+ 		if self.tags.has_key(tag.lower()):
+ 			raise HTMLNotAllowedError('line %i: The tag %r is not allowed in %r which cannot have %r.' % (
+ 				lineNum, tag, self.name, self.tags.keys()), line=lineNum, enounteredTag=tag, containingTag=self.name, cannotHave=self.tags.keys())
+ 
+ 
+ configClassForName = {
+ 	'canOnlyHave':   TagCanOnlyHaveConfig,
+ 	'cannotHave': TagCannotHaveConfig,
+ }