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###################################################################################################
# _builder.py
#
# $Id: _builder.py,v 1.3 2003/11/21 07:29:45 dnordmann Exp $
# $Name: $
# $Author: dnordmann $
# $Revision: 1.3 $
#
# Implementation of class Builder (see below).
#
# This program is free software; you can redistribute it and/or
# modify it under the terms of the GNU General Public License
# as published by the Free Software Foundation; either version 2
# of the License, or (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program; if not, write to the Free Software
# Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
###################################################################################################
# Imports
from Shared.DC.xml import pyexpat
import time
import Globals
# Product Imports.
import _globals
###################################################################################################
# class ParseError(Exception):
#
# General exception class to indicate parsing errors.
###################################################################################################
class ParseError(Exception): pass
###################################################################################################
# class Builder
#
# Implements a builder class (cp. design pattern "BUILDER") to build a tree of ZOPE objects
# out of an XML formatted document. Uses the class "pyexpat" (cp. module "Shared.DC.xml") for
# parsing the XML document. The general approach of the XML parser "pyexpat" is event driven,
# where handler methods are called on occurence of XML tags. Builder redirects these events to
# a set of own handler methods (see below). To build up the object tree, Builder provides the
# following functionality:
#
# 1. Usually, the occurence of a XML tag induces the instanciation of a new node object. Therefore,
# Builder contains a mapping table ("dGlobalAttrs"), that maps XML tags to python classes. The
# handler method "Builder.OnStartElement()" creates a node object of the corresponding class.
# This node object is then made current.
#
# 2. In General, events are directed to the current node object. Therefore, they have to contain
# a set of interface methods (see below). The node objects are responsible for handling these
# events. This includes the insertion into the object tree as well as the interpretation of
# XML tag parameters.
#
# 3. A dedicated root object is managed by Builder. The root object may be predefined or created
# during the parsing process.
#
# Builder is usually used as a mix-in base class for other classes. For usage, the following
# issues must be taken into consideration:
#
# 1. Overwrite "dGlobalAttrs" with a dictionary, that maps XML-Tags to python classes.
# 2. Call "Builder.parse()" to initiate the parsing and building process.
# 3. Equip all python classes with the following interface methods:
#
# - xmlOnStartElement(self, dTagName, dTagAttrs, oParentNode, oRoot)
# - xmlOnCharacterData(self, sData, bInCData)
# - xmlOnEndElement(self)
# - xmlOnUnknownStartTag(self, sTagName, dTagAttrs)
# - xmlOnUnknownEndTag(self, sTagName)
# - xmlGetTagName(self)
# - xmlGetParent(self)
#
###################################################################################################
class Builder:
""" Builder """
######## class variables ########
iBufferSize=1028 * 32 # buffer size for XML file parsing
###############################################################################################
# Builder.__init__(self):
#
# Constructor.
###############################################################################################
def __init__(self):
""" Builder.__init__ """
self.oRoot = None # root node of object tree
self.oCurrNode = None # current node
self.bInRootTag = 0 # inside root tag?
self.bInCData = 0 # inside CDATA section?
###############################################################################################
# Builder.parse(self, root, input):
#
# Parse a given XML document and build a recursive object tree via event handler.
#
# IN: input = XML document as string
# = XML document as file object
# root = pre-set root node for object tree (prevents the creation of a root object, when
# the first root tag appears in XML-document)
# = None, if no root object is given (will be instanciated)
#
# OUT: root object
# None, if nothing was parsed
###############################################################################################
def parse(self, input, root=None, bInRootTag=0):
""" Builder.parse """
# prepare builder
self._unknownTagName = None
self.oRoot = root
self.oRootNode = None
self.oCurrNode = None
self.bInRootTag = bInRootTag
self.bInCData = 0
if bInRootTag:
self.oCurrNode = root
# create parser object
p = pyexpat.ParserCreate()
# connect parser object with handler methods
p.StartElementHandler = self.OnStartElement
p.EndElementHandler = self.OnEndElement
p.CharacterDataHandler = self.OnCharacterData
p.StartCdataSectionHandler = self.OnStartCData
p.EndCdataSectionHandler = self.OnEndCData
p.ProcessingInstructionHandler = self.OnProcessingInstruction
p.CommentHandler = self.OnComment
p.StartNamespaceDeclHandler = self.OnStartNamespaceDecl
p.EndNamespaceDeclHandler = self.OnEndNamespaceDecl
#### parsing ####
#++ print "#### parsing ####"
if type(input)=='string':
# input is a string!
rv = p.Parse(input, 1)
else:
# input is a file object!
while 1:
if Globals.DatabaseVersion == '3':
get_transaction().commit(1)
v=input.read(self.iBufferSize)
if v=="":
rv = 1
break
rv = p.Parse(v, 0)
if not rv:
break
# raise parser exception
if not rv:
raise ParseError('%s at line %s' % (pyexpat.ErrorString(p.ErrorCode), p.ErrorLineNumber))
####
return self.oRootNode
###############################################################################################
# Builder.OnStartElement(self, name, attrs):
#
# Handler of XML-Parser:
# Called at the start of a XML element (resp. on occurence of a XML start tag).
# Usually, the occurence of a XML tag induces the instanciation of a new node object. Therefore,
# Builder contains a mapping table ("dGlobalAttrs"), that maps XML tags to python classes. The
# newly created node object is then made current. If no matching class is found for a XML tag,
# the event handler "xmlOnUnknownStart()" is called on the current object.
#
# IN: name = element name (=tag name)
# attrs = dictionary of element attributes
###############################################################################################
def OnStartElement(self, name, attrs):
""" Builder.OnStartElement """
#++ if _globals.debug: print "OnStartElement(" + str(name) + "," + str(attrs) + ") "
if self.bInRootTag or \
self.oRoot == None or \
(self.oRoot.id == self.getDocumentElement().id and \
self.dGlobalAttrs.has_key(name) and \
self.dGlobalAttrs[name]['obj_class'] is not None):
#++ print "We are inside the XML root tag OR no root object is set"
#++ print "-> instanciate node object in any case"
if self.dGlobalAttrs.has_key(name) and \
self.dGlobalAttrs[name]['obj_class'] is not None:
# class defined for tag!
if self.oCurrNode==None and self.oRoot!=None and self.oRoot.id==self.getDocumentElement().id:
self.oCurrNode = self.oRoot
# create node instance
_globals.writeLog(" create new object <" + name + "> in " + str(self.oCurrNode))
if 'id_fix' in attrs:
id = attrs[attrs.index('id_fix')+1]
elif 'id_prefix' in attrs:
prefix = attrs[attrs.index('id_prefix')+1]
id = self.oCurrNode.getNewId(prefix)
elif 'id' in attrs:
id = attrs[attrs.index('id')+1]
prefix = _globals.id_prefix(id)
id = self.oCurrNode.getNewId(prefix)
else:
id = self.oCurrNode.getNewId()
sort_id = self.oCurrNode.getNewSortId()
##### Create ####
newNode = self.dGlobalAttrs[name]['obj_class'](id,sort_id)
self.oCurrNode._setObject(newNode.id, newNode)
newNode = getattr(self.oCurrNode,newNode.id)
##### Meta Objects ####
if newNode.meta_type == 'ZMSCustom':
meta_id = attrs[attrs.index('meta_id')+1]
if meta_id not in self.getMetaobjIds():
raise ParseError("Unknown meta_id (" + meta_id + "): no special object available!") # no special object available!
newNode.meta_id = meta_id
##### Object State ####
newNode.resetObjVersion()
obj_attrs = newNode.getObjAttrs()
for lang in self.getLangIds():
req = {'lang':lang,'preview':'preview'}
##### Object State ####
newNode.setObjStateNew(req)
##### Init Properties ####
if 'active' in obj_attrs.keys():
newNode.setObjProperty('active',1,lang)
newNode.setObjProperty('change_uid','xml',lang)
newNode.setObjProperty('change_dt',time.time(),lang)
_globals.writeLog(" object with id " + str(newNode.id) + " of class " + str(newNode.__class__) + " created in " + str(self.oCurrNode.__class__))
if self.oRoot is None: # root object set?
self.oRoot = newNode # -> set root node
# notify new node
newNode.xmlOnStartElement(name, attrs, self.oCurrNode, self.oRoot)
# set new node as current node
self.oCurrNode = newNode
else:
# no class defined for tag
# -> offer to current object
if self.oCurrNode==None:
raise ParseError("Unknown tag (" + name + "): no current object available!") # no current object available!
if not self.oCurrNode.xmlOnUnknownStartTag(name, attrs):
if self._unknownTagName == None:
self._unknownTagName = name
#++ print "Unknown start-tag (" + name + "): current object did not accept tag!" # current object did not accept tag!
# raise ParseError("Unknown start-tag (" + name + "): current object did not accept tag!") # current object did not accept tag!
else:
#++ print "we have encountered the XML root tag and a root object is predefined"
#++ print "-> simply notify root object"
self.oRoot.xmlOnStartElement(name, attrs, None, self.oRoot)
# set root node as current node
self.oCurrNode = self.oRoot
# we are inside the XML root now!
self.bInRootTag=1
if self.oRootNode is None:
self.oRootNode = self.oCurrNode
###############################################################################################
# Builder.OnEndElement(self, name):
#
# Handler of XML-Parser:
# Called at the end of a XML element (resp. on occurence of a XML end tag).
#
# IN: name = element name (=tag name)
###############################################################################################
def OnEndElement(self, name):
""" Builder.OnEndElement """
#++ if _globals.debug: print "OnEndElement(" + str(name) + ")"
# do we have a current node?
if self.oCurrNode==None:
raise ParseError("Unmatching end tag (" + name + ")")
# is this the right tag name?
if name==self.oCurrNode.xmlGetTagName():
# notify current node
self.oCurrNode.xmlOnEndElement()
parent = self.oCurrNode.xmlGetParent()
# set parent node as current node
self.oCurrNode = parent
else:
if self.dGlobalAttrs.has_key(name) and \
self.dGlobalAttrs[name]['obj_class'] is not None:
if self.dGlobalAttrs.has_key(self.oCurrNode.xmlGetTagName()) and \
self.dGlobalAttrs[self.oCurrNode.xmlGetTagName()]['obj_class'] is not None:
# tag name is known, but not valid at this place!
raise ParseError("Unmatching end tag (/" + name + "), expected(/" + self.oCurrNode.xmlGetTagName() + ")")
else:
# tag name is unknown -> offer it to current object
if not self.oCurrNode.xmlOnUnknownEndTag(name):
if name == self._unknownTagName:
self._unknownTagName = None
#++ print "Unknown end-tag (/" + name + ")" # current object did not accept tag!
# raise ParseError("Unknown end-tag (" + name + ")") # current object did not accept tag!
###############################################################################################
# Builder.OnCharacterData(self, data):
#
# Handler of XML-Parser:
# Called after plain character data was parsed. Forwards the character data to the current
# node. The class attribute "bInCData" determines, wether the character data is nested in a
# CDATA block.
#
# IN: data = character data string
###############################################################################################
def OnCharacterData(self, data):
""" Builder.OnCharacterData """
#++ print "OnCharacterData(" + str(data) + ")"
# do we have a current node?
if self.oCurrNode==None:
raise ParseError("Unexpected character data found")
# notify current node
self.oCurrNode.xmlOnCharacterData(data, self.bInCData)
###############################################################################################
# Builder.OnStartCData(self):
#
# Handler of XML-Parser:
# Called at the start of a CDATA block (resp. on occurence of the "CDATA[" tag).
###############################################################################################
def OnStartCData(self):
""" Builder.OnStartCData """
self.bInCData=1
###############################################################################################
# Builder.OnEndCData(self):
#
# Handler of XML-Parser:
# Called at the end of a CDATA block (resp. on occurence of the "]" tag).
###############################################################################################
def OnEndCData(self):
""" Builder.OnEndCData """
self.bInCData=0
###############################################################################################
# Builder.OnProcessingInstruction(self, target, data):
#
# Handler of XML-Parser:
# Called on occurence of a processing instruction.
#
# IN: target = target (processing instruction)
# data = dictionary of data
###############################################################################################
def OnProcessingInstruction(self, target, data):
""" Builder.OnProcessingInstruction """
pass # ignored
###############################################################################################
# Builder.OnComment(self, data):
#
# Handler of XML-Parser:
# Called on occurence of a comment.
#
# IN: data = comment string
###############################################################################################
def OnComment(self, data):
""" Builder.OnComment """
pass # ignored
###############################################################################################
# Builder.OnStartNamespaceDecl(self, prefix, uri):
#
# Handler of XML-Parser:
# Called at the start of a namespace declaration.
#
# IN: prefix = prefix of namespace
# uri = namespace identifier
###############################################################################################
def OnStartNamespaceDecl(self, prefix, uri):
""" Builder.OnStartNamespaceDecl """
pass # ignored
###############################################################################################
# Builder.OnEndNamespaceDecl(self, prefix):
#
# Handler of XML-Parser:
# Called at the end of a namespace declaration.
#
# IN: prefix = prefix of namespace
###############################################################################################
def OnEndNamespaceDecl(self, prefix):
""" Builder.OnEndNamespaceDecl """
pass # ignored
###################################################################################################
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