Paul Prescod <paul@prescod.net>:

SAX interfaces for Python.

1 files changed, 225 insertions, 0 deletions

diff --git a/Lib/xml/sax/xmlreader.py b/Lib/xml/sax/xmlreader.py
new file mode 100644
index 0000000..b66ef1c
--- /dev/null
+++ b/Lib/xml/sax/xmlreader.py
@@ -0,0 +1,225 @@
+import handler
+
+"""An XML Reader is the SAX 2 name for an XML parser. XML Parsers
+should be based on this code. """
+# ===== XMLREADER =====
+
+class XMLReader:
+    def __init__(self):
+	self._cont_handler = handler.ContentHandler()
+	#self._dtd_handler  = handler.DTDHandler()
+	#self._ent_handler  = handler.EntityResolver()
+	self._err_handler  = handler.ErrorHandler()
+
+    def parse(self, source):
+	"Parse an XML document from a system identifier or an InputSource."
+        raise NotImplementedError("This method must be implemented!")
+
+    def getContentHandler(self):
+        "Returns the current ContentHandler."
+        return self._cont_handler
+
+    def setContentHandler(self, handler):
+        "Registers a new object to receive document content events."
+        self._cont_handler = handler
+        
+    def getDTDHandler(self):
+        "Returns the current DTD handler."
+        return self._dtd_handler
+        
+    def setDTDHandler(self, handler):
+	"Register an object to receive basic DTD-related events."
+	self._dtd_handler = handler
+
+    def getEntityResolver(self):
+        "Returns the current EntityResolver."
+        return self._ent_handler
+        
+    def setEntityResolver(self, resolver):
+	"Register an object to resolve external entities."
+	self._ent_handler = resolver
+
+    def getErrorHandler(self):
+        "Returns the current ErrorHandler."
+        return self._err_handler
+        
+    def setErrorHandler(self, handler):
+	"Register an object to receive error-message events."
+	self._err_handler = handler
+
+    def setLocale(self, locale):
+        """Allow an application to set the locale for errors and warnings. 
+   
+        SAX parsers are not required to provide localisation for errors
+        and warnings; if they cannot support the requested locale,
+        however, they must throw a SAX exception. Applications may
+        request a locale change in the middle of a parse."""
+        raise SAXNotSupportedException("Locale support not implemented")
+    
+    def getFeature(self, name):
+        "Looks up and returns the state of a SAX2 feature."
+        raise SAXNotRecognizedException("Feature '%s' not recognized" % name)
+
+    def setFeature(self, name, state):
+        "Sets the state of a SAX2 feature."
+        raise SAXNotRecognizedException("Feature '%s' not recognized" % name)
+
+    def getProperty(self, name):
+        "Looks up and returns the value of a SAX2 property."
+        raise SAXNotRecognizedException("Property '%s' not recognized" % name)
+
+    def setProperty(self, name, value):
+        "Sets the value of a SAX2 property."
+        raise SAXNotRecognizedException("Property '%s' not recognized" % name)
+
+ 
+class IncrementalParser(XMLReader):
+    """This interface adds three extra methods to the XMLReader
+    interface that allow XML parsers to support incremental
+    parsing. Support for this interface is optional, since not all
+    underlying XML parsers support this functionality.
+
+    When the parser is instantiated it is ready to begin accepting
+    data from the feed method immediately. After parsing has been
+    finished with a call to close the reset method must be called to
+    make the parser ready to accept new data, either from feed or
+    using the parse method.
+
+    Note that these methods must _not_ be called during parsing, that
+    is, after parse has been called and before it returns.
+
+    By default, the class also implements the parse method of the XMLReader
+    interface using the feed, close and reset methods of the
+    IncrementalParser interface as a convenience to SAX 2.0 driver
+    writers."""
+    def __init__(self, bufsize=2**16 ):
+        self._bufsize=bufsize
+        XMLReader.__init__( self )
+    
+    def parse(self, source):
+        self.prepareParser(source)
+        #FIXME: do some type checking: could be already stream, URL or
+        #       filename
+        inf=open( source )
+        buffer = inf.read(self._bufsize)
+        while buffer != "":
+            self.feed(buffer)
+            buffer = inf.read(self._bufsize)
+        self.close()
+        self.reset()
+
+    def feed(self, data):        
+        """This method gives the raw XML data in the data parameter to
+        the parser and makes it parse the data, emitting the
+        corresponding events. It is allowed for XML constructs to be
+        split across several calls to feed.
+
+        feed may raise SAXException."""
+        raise NotImplementedError("This method must be implemented!")
+    def prepareParser(self, source):
+        """This method is called by the parse implementation to allow
+        the SAX 2.0 driver to prepare itself for parsing."""
+        raise NotImplementedError("prepareParser must be overridden!")
+
+    def close(self):
+        """This method is called when the entire XML document has been
+        passed to the parser through the feed method, to notify the
+        parser that there are no more data. This allows the parser to
+        do the final checks on the document and empty the internal
+        data buffer.
+
+        The parser will not be ready to parse another document until
+        the reset method has been called.
+
+        close may raise SAXException."""
+        raise NotImplementedError("This method must be implemented!")
+
+    def reset(self):
+        """This method is called after close has been called to reset
+        the parser so that it is ready to parse new documents. The
+        results of calling parse or feed after close without calling
+        reset are undefined."""
+        raise NotImplementedError("This method must be implemented!")
+
+# ===== LOCATOR =====
+class Locator:
+    """Interface for associating a SAX event with a document
+    location. A locator object will return valid results only during
+    calls to DocumentHandler methods; at any other time, the
+    results are unpredictable."""
+
+    def getColumnNumber(self):
+	"Return the column number where the current event ends."
+	return -1
+
+    def getLineNumber(self):
+	"Return the line number where the current event ends."
+	return -1
+
+    def getPublicId(self):
+	"Return the public identifier for the current event."
+	return None
+
+    def getSystemId(self):
+	"Return the system identifier for the current event."
+	return None
+
+# --- AttributesImpl
+class AttributesImpl:
+    def __init__(self, attrs, rawnames):
+        self._attrs = attrs
+        self._rawnames = rawnames
+
+    def getLength(self):
+        return len(self._attrs)
+
+    def getType(self, name):
+        return "CDATA"
+
+    def getValue(self, name):
+        return self._attrs[name]
+
+    def getValueByQName(self, name):
+        return self._attrs[self._rawnames[name]]
+
+    def getNameByQName(self, name):
+        return self._rawnames[name]
+
+    def getNames(self):
+        return self._attrs.keys()
+
+    def getQNames(self):
+        return self._rawnames.keys()    
+
+    def __len__(self):
+        return len(self._attrs)
+
+    def __getitem__(self, name):
+        return self._attrs[name]
+
+    def keys(self):
+        return self._attrs.keys()
+
+    def has_key(self, name):
+        return self._attrs.has_key(name)
+
+    def get(self, name, alternative=None):
+        return self._attrs.get(name, alternative)
+
+    def copy(self):
+        return self.__class__(self._attrs, self._rawnames)
+
+    def items(self):
+        return self._attrs.items()
+
+    def values(self):
+        return self._attrs.values()
+
+def _test():
+    XMLReader()
+    IncrementalParser()
+    Locator()
+    AttributesImpl()
+
+if __name__=="__main__":
+    _test()