xml.sax — Support for SAX2 parsers
xml.sax package provides a number of modules which implement the
Simple API for XML (SAX) interface for Python. The package itself provides the
SAX exceptions and the convenience functions which will be most used by users of
the SAX API.
The convenience functions are:
Create and return a SAX
XMLReaderobject. The first parser found will be used. If parser_list is provided, it must be a sequence of strings which name modules that have a function named
create_parser(). Modules listed in parser_list will be used before modules in the default list of parsers.
parse(filename_or_stream, handler, error_handler=handler.ErrorHandler())
Create a SAX parser and use it to parse a document. The document, passed in as filename_or_stream, can be a filename or a file object. The handler parameter needs to be a SAX
ContentHandlerinstance. If error_handler is given, it must be a SAX
ErrorHandlerinstance; if omitted,
SAXParseExceptionwill be raised on all errors. There is no return value; all work must be done by the handler passed in.
parseString(string, handler, error_handler=handler.ErrorHandler())
Changed in version 3.5: Added support of
A typical SAX application uses three kinds of objects: readers, handlers and input sources. “Reader” in this context is another term for parser, i.e. some piece of code that reads the bytes or characters from the input source, and produces a sequence of events. The events then get distributed to the handler objects, i.e. the reader invokes a method on the handler. A SAX application must therefore obtain a reader object, create or open the input sources, create the handlers, and connect these objects all together. As the final step of preparation, the reader is called to parse the input. During parsing, methods on the handler objects are called based on structural and syntactic events from the input data.
For these objects, only the interfaces are relevant; they are normally not
instantiated by the application itself. Since Python does not have an explicit
notion of interface, they are formally introduced as classes, but applications
may use implementations which do not inherit from the provided classes. The
XMLReader interfaces are defined in the
xml.sax.xmlreader. The handler interfaces are defined in
xml.sax.handler. For convenience,
InputSource (which is often
instantiated directly) and the handler classes are also available from
xml.sax. These interfaces are described below.
In addition to these classes,
xml.sax provides the following exception
Encapsulate an XML error or warning. This class can contain basic error or warning information from either the XML parser or the application: it can be subclassed to provide additional functionality or to add localization. Note that although the handlers defined in the
ErrorHandlerinterface receive instances of this exception, it is not required to actually raise the exception — it is also useful as a container for information.
When instantiated, msg should be a human-readable description of the error. The optional exception parameter, if given, should be
Noneor an exception that was caught by the parsing code and is being passed along as information.
This is the base class for the other SAX exception classes.
SAXParseException(msg, exception, locator)
SAXExceptionraised on parse errors. Instances of this class are passed to the methods of the SAX
ErrorHandlerinterface to provide information about the parse error. This class supports the SAX
Locatorinterface as well as the
SAXExceptionraised when a SAX
XMLReaderis asked to enable a feature that is not supported, or to set a property to a value that the implementation does not support. SAX applications and extensions may use this class for similar purposes.
- SAX: The Simple API for XML
- This site is the focal point for the definition of the SAX API. It provides a Java implementation and online documentation. Links to implementations and historical information are also available.
- Definitions of the interfaces for application-provided objects.
- Convenience functions for use in SAX applications.
- Definitions of the interfaces for parser-provided objects.
20.9.1. SAXException Objects
SAXException exception class supports the following methods:
Return a human-readable message describing the error condition.
Return an encapsulated exception object, or