418 lines
18 KiB
Python
Executable file
418 lines
18 KiB
Python
Executable file
# ------------------------------------------------------------------------------
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# Appy is a framework for building applications in the Python language.
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# Copyright (C) 2007 Gaetan Delannay
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# This program is free software; you can redistribute it and/or
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# modify it under the terms of the GNU General Public License
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# as published by the Free Software Foundation; either version 2
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# of the License, or (at your option) any later version.
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# This program is distributed in the hope that it will be useful,
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# but WITHOUT ANY WARRANTY; without even the implied warranty of
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# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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# GNU General Public License for more details.
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# You should have received a copy of the GNU General Public License
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# along with this program; if not, write to the Free Software
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# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301,USA.
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# ------------------------------------------------------------------------------
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import xml.sax
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from xml.sax.handler import ContentHandler, ErrorHandler
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from xml.sax.xmlreader import InputSource
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from StringIO import StringIO
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# ------------------------------------------------------------------------------
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class XmlElement:
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'''Represents an XML tag.'''
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def __init__(self, elem, attrs=None, nsUri=None):
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'''An XmlElement instance may represent:
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- an already parsed tag (in this case, p_elem may be prefixed with a
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namespace);
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- the definition of an XML element (in this case, no namespace can be
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found in p_elem; but a namespace URI may be defined in p_nsUri).'''
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self.elem = elem
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self.attrs = attrs
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if elem.find(':') != -1:
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self.ns, self.name = elem.split(':')
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else:
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self.ns = ''
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self.name = elem
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self.nsUri = nsUri
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def equalsTo(self, other, namespaces=None):
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'''Does p_elem == p_other? If a p_namespaces dict is given, p_other must
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define a nsUri.'''
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res = None
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if namespaces:
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res = self.elem == ('%s:%s' % (namespaces[other.nsUri], other.name))
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else:
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res = self.elem == other.elem
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return res
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def __repr__(self):
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res = self.elem
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if self.attrs:
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res += '('
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for attrName, attrValue in self.attrs.items():
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res += '%s="%s"' % (attrName, attrValue)
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res += ')'
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return res
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def getFullName(self, namespaces=None):
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'''Gets the name of the element including the namespace prefix.'''
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if not namespaces:
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res = self.elem
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else:
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res = '%s:%s' % (namespaces[self.nsUri], self.name)
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return res
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class XmlEnvironment:
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'''An XML environment remembers a series of elements during a SAX parsing.
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This class is an abstract class that gathers basic things like
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namespaces.'''
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def __init__(self):
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# This dict contains the xml namespace declarations encountered so far
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self.namespaces = {} # ~{s_namespaceUri:s_namespaceName}~
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self.currentElem = None # The currently parsed element
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self.parser = None
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def manageNamespaces(self, attrs):
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'''Manages namespaces definitions encountered in p_attrs.'''
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for attrName, attrValue in attrs.items():
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if attrName.startswith('xmlns:'):
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self.namespaces[attrValue] = attrName[6:]
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def ns(self, nsUri):
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'''Returns the namespace corresponding to o_nsUri.'''
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return self.namespaces[nsUri]
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class XmlParser(ContentHandler, ErrorHandler):
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'''Basic XML content handler that does things like :
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- remembering the currently parsed element;
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- managing namespace declarations.'''
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def __init__(self, env=None, caller=None):
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'''p_env should be an instance of a class that inherits from
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XmlEnvironment: it specifies the environment to use for this SAX
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parser.'''
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ContentHandler.__init__(self)
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if not env: env = XmlEnvironment()
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self.env = env
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self.env.parser = self
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self.caller = caller # The class calling this parser
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self.parser = xml.sax.make_parser() # Fast, standard expat parser
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self.res = None # The result of parsing.
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def setDocumentLocator(self, locator):
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self.locator = locator
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return self.env
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def endDocument(self):
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return self.env
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def startElement(self, elem, attrs):
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self.env.manageNamespaces(attrs)
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if self.env.currentElem == None:
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self.env.currentElem = XmlElement(elem, attrs=attrs)
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else:
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# Reuse the exiting instance in order to avoid creating one instance
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# every time an elem is met in the XML file.
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self.env.currentElem.__init__(elem, attrs)
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return self.env
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def endElement(self, elem):
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self.env.currentElem.__init__(elem)
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return self.env
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def characters(self, content):
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return self.env
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def parse(self, xmlContent, source='string'):
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'''Parsers the XML file or string p_xmlContent.'''
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try:
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from cStringIO import StringIO
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except ImportError:
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from StringIO import StringIO
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self.parser.setContentHandler(self)
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self.parser.setErrorHandler(self)
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inputSource = InputSource()
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if source == 'string':
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inputSource.setByteStream(StringIO(xmlContent))
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else:
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inputSource.setByteStream(xmlContent)
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self.parser.parse(inputSource)
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return self.res
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# ------------------------------------------------------------------------------
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from appy.shared import UnmarshalledObject, UnmarshalledFile
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try:
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from DateTime import DateTime
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except ImportError:
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DateTime = 'unicode'
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class XmlUnmarshaller(XmlParser):
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'''This class allows to parse a XML file and recreate the corresponding web
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of Python objects. This parser assumes that the XML file respects this
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convention: any tag may define in attribute "type" storing the type of
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its content, which may be:
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bool * int * float * long * DateTime * tuple * list * object
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If "object" is specified, it means that the tag contains sub-tags, each
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one corresponding to the value of an attribute for this object.
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if "tuple" is specified, it will be converted to a list.'''
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def __init__(self, klass=None):
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XmlParser.__init__(self)
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self.klass = klass # If a klass is given here, instead of creating
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# a root UnmarshalledObject instance, we will create an instance of this
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# class (only if the root object is an object; this does not apply if
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# it is a list or tuple; yes, technically the root tag can be a list or
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# tuple even if it is silly because only one root tag can exist). But be
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# careful: we will not call the constructor of this class. We will
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# simply create an instance of UnmarshalledObject and dynamically change
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# the class of the created instance to this class.
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def startDocument(self):
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self.res = None # The resulting web of Python objects
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# (UnmarshalledObject instances).
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self.env.containerStack = [] # The stack of current "containers" where
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# to store the next parsed element. A container can be a list, a tuple,
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# an object (the root object of the whole web or a sub-object).
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self.env.currentBasicType = None # Will hold the name of the currently
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# parsed basic type (unicode, float...)
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self.env.currentContent = '' # We store here the content of tags.
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containerTags = ('tuple', 'list', 'object', 'file')
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numericTypes = ('bool', 'int', 'float', 'long')
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def startElement(self, elem, attrs):
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e = XmlParser.startElement(self, elem, attrs)
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# Determine the type of the element.
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elemType = 'unicode' # Default value
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if attrs.has_key('type'):
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elemType = attrs['type']
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if elemType in self.containerTags:
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# I must create a new container object.
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if elemType == 'object': newObject = UnmarshalledObject()
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elif elemType == 'tuple': newObject = [] # Tuples become lists
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elif elemType == 'list': newObject = []
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elif elemType == 'file':
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newObject = UnmarshalledFile()
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if attrs.has_key('name'):
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newObject.name = attrs['name']
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if attrs.has_key('mimeType'):
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newObject.mimeType = attrs['mimeType']
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else: newObject = UnmarshalledObject()
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# Store the value on the last container, or on the root object.
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self.storeValue(elem, newObject)
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# Push the new object on the container stack
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e.containerStack.append(newObject)
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else:
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e.currentBasicType = elemType
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def storeValue(self, name, value):
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'''Stores the newly parsed p_value (contained in tag p_name) on the
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current container in environment p_e.'''
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e = self.env
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# Where must I store this value?
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if not e.containerStack:
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# I store the object at the root of the web.
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self.res = value
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if self.klass and isinstance(value, UnmarshalledObject):
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self.res.__class__ = self.klass
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else:
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currentContainer = e.containerStack[-1]
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if isinstance(currentContainer, list):
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currentContainer.append(value)
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elif isinstance(currentContainer, UnmarshalledFile):
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currentContainer.content += value
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else:
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# Current container is an object
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setattr(currentContainer, name, value)
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def characters(self, content):
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e = XmlParser.characters(self, content)
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if e.currentBasicType:
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e.currentContent += content
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def endElement(self, elem):
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e = XmlParser.endElement(self, elem)
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if e.currentBasicType:
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# Get and convert the value of this field
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if e.currentBasicType in self.numericTypes:
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try:
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exec 'value = %s' % e.currentContent.strip()
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except SyntaxError:
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value = None
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elif e.currentBasicType == 'DateTime':
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value = DateTime(e.currentContent.strip())
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elif e.currentBasicType == 'base64':
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value = e.currentContent.decode('base64')
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else:
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value = e.currentContent.strip()
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# Store the value on the last container
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self.storeValue(elem, value)
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# Clean the environment
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e.currentBasicType = None
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e.currentContent = ''
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else:
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e.containerStack.pop()
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# Alias 'unmarshall' -> 'parse'
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unmarshall = XmlParser.parse
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# ------------------------------------------------------------------------------
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class XmlMarshaller:
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'''This class allows to produce a XML version of a Python object, which
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respects some conventions as described in the doc of the corresponding
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Unmarshaller (see above).'''
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xmlPrologue = '<?xml version="1.0" encoding="utf-8"?>'
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xmlEntities = {'<': '<', '>': '>', '&': '&', '"': '"',
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"'": '''}
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trueFalse = {True: 'True', False: 'False'}
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sequenceTypes = (tuple, list)
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rootElementName = 'xmlPythonData'
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fieldsToMarshall = 'all'
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fieldsToExclude = []
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atFiles = ('image', 'file') # Types of archetypes fields that contain files.
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def dumpString(self, res, s):
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'''Dumps a string into the result.'''
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# Replace special chars by XML entities
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for c in s:
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if self.xmlEntities.has_key(c):
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res.write(self.xmlEntities[c])
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else:
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res.write(c)
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def dumpFile(self, res, v):
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'''Dumps a file into the result.'''
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# p_value contains the (possibly binary) content of a file. We will
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# encode it in Base64, in one or several parts.
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res.write('<part type="base64" number="1">')
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if hasattr(v, 'data'):
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# The file is an Archetypes file.
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valueType = v.data.__class__.__name__
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if valueType == 'Pdata':
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# There will be several parts.
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res.write(v.data.data.encode('base64'))
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# Write subsequent parts
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nextPart = v.data.next
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nextPartNumber = 2
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while nextPart:
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res.write('</part>') # Close the previous part
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res.write('<part type="base64" number="%d">'%nextPartNumber)
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res.write(nextPart.data.encode('base64'))
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nextPart = nextPart.next
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nextPartNumber += 1
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else:
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res.write(v.data.encode('base64'))
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else:
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res.write(v.encode('base64'))
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res.write('</part>')
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def dumpValue(self, res, value, fieldType):
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'''Dumps the XML version of p_value to p_res.'''
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if fieldType == 'file':
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self.dumpFile(res, value)
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elif fieldType == 'ref':
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if value:
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if type(value) in self.sequenceTypes:
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for elem in value:
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self.dumpField(res, 'url', elem.absolute_url())
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else:
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self.dumpField(res, 'url', value.absolute_url())
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elif type(value) in self.sequenceTypes:
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# The previous condition must be checked before this one because
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# Referred objects may be stored in lists or tuples, too.
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for elem in value:
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self.dumpField(res, 'e', elem)
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elif isinstance(value, basestring):
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self.dumpString(res, value)
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elif isinstance(value, bool):
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res.write(self.trueFalse[value])
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else:
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res.write(value)
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def dumpField(self, res, fieldName, fieldValue, fieldType='basic'):
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'''Dumps in p_res, the value of the p_field for p_instance.'''
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res.write('<'); res.write(fieldName);
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# Dump the type of the field as an XML attribute
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fType = None # No type will mean "unicode".
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if fieldType == 'file': fType ='file'
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elif fieldType == 'ref': fType = 'list'
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elif isinstance(fieldValue, bool): fType = 'bool'
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elif isinstance(fieldValue, int): fType = 'int'
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elif isinstance(fieldValue, float): fType = 'float'
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elif isinstance(fieldValue, long): fType = 'long'
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elif isinstance(fieldValue, tuple): fType = 'tuple'
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elif isinstance(fieldValue, list): fType = 'list'
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elif fieldValue.__class__.__name__ == 'DateTime': fType = 'DateTime'
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if fType: res.write(' type="%s"' % fType)
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# Dump other attributes if needed
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if type(fieldValue) in self.sequenceTypes:
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res.write(' count="%d"' % len(fieldValue))
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if fieldType == 'file':
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if hasattr(fieldValue, 'content_type'):
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res.write(' mimeType="%s"' % fieldValue.content_type)
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if hasattr(fieldValue, 'filename'):
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res.write(' name="')
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self.dumpString(res, fieldValue.filename)
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res.write('"')
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res.write('>')
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# Dump the field value
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self.dumpValue(res, fieldValue, fieldType)
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res.write('</'); res.write(fieldName); res.write('>')
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def marshall(self, instance, objectType='popo'):
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'''Returns in a StringIO the XML version of p_instance. If p_instance
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corresponds to a Plain Old Python Object, specify 'popo' for
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p_objectType. If p_instance corresponds to an Archetypes object
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(Zope/Plone), specify 'archetype' for p_objectType.'''
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res = StringIO()
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# Dump the XML prologue and root element
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res.write(self.xmlPrologue)
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res.write('<'); res.write(self.rootElementName)
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res.write(' type="object">')
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# Dump the value of the fields that must be dumped
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if objectType == 'popo':
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for fieldName, fieldValue in instance.__dict__.iteritems():
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mustDump = False
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if fieldName in self.fieldsToExclude:
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mustDump = False
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elif self.fieldsToMarshall == 'all':
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mustDump = True
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else:
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if (type(self.fieldsToMarshall) in self.sequenceTypes) and \
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(fieldName in self.fieldsToMarshall):
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mustDump = True
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if mustDump:
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self.dumpField(res, fieldName, fieldValue)
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elif objectType == 'archetype':
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fields = instance.schema.fields()
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for field in instance.schema.fields():
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# Dump only needed fields
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mustDump = False
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if field.getName() in self.fieldsToExclude:
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mustDump = False
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elif (self.fieldsToMarshall == 'all') and \
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(field.schemata != 'metadata'):
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mustDump = True
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elif self.fieldsToMarshall == 'all_with_metadata':
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mustDump = True
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else:
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if (type(self.fieldsToMarshall) in self.sequenceTypes) and \
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(field.getName() in self.fieldsToMarshall):
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mustDump = True
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if mustDump:
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fieldType = 'basic'
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if field.type in self.atFiles:
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fieldType = 'file'
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elif field.type == 'reference':
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fieldType = 'ref'
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self.dumpField(res, field.getName(), field.get(instance),
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fieldType=fieldType)
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self.marshallSpecificElements(instance, res)
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# Return the result
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res.write('</'); res.write(self.rootElementName); res.write('>')
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data = res.getvalue()
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res.close()
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return data
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def marshallSpecificElements(self, instance, res):
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'''You can use this marshaller as a base class for creating your own.
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In this case, this method will be called by the marshall method
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for allowing your concrete marshaller to insert more things in the
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result. p_res is the StringIO buffer where the result of the
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marshalling process is currently dumped; p_instance is the instance
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currently marshalled.'''
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# ------------------------------------------------------------------------------
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