Python/XML Reference Guide
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                         Python/XML Reference Guide
                                      
                   The Python/XML Special Interest Group
                                      
                             xml-sig@python.org
                       (edited by akuchling@acm.org)
                                      
  Abstract:
  
   XML is the eXtensible Markup Language, a subset of SGML, intended to
   allow the creation and processing of application-specific markup
   languages. Python makes an excellent language for processing XML data.
   This document is the reference manual for the Python/XML package,
   containing several XML modules.
   
   This is a draft document; 'XXX' in the text indicates that something
   has to be filled in later, or rewritten, or verified, or something.

   THIS DOCUMENT IS SIGNIFICANTLY OUTDATED, DO NOT USE IT AS A BASIS OF
   APPLICATION DEVELOPMENT.
   
Contents

     * Contents
     * 1. xml.arch.xmlarch
          + 1.1 ArchDocHandler methods
          + 1.2 Architecture methods
          + 1.3 ArchParseState methods
          + 1.4 ArchException methods
          + 1.5 AttributeParser methods
          + 1.6 Normalizer methods
     * 2. xml.parsers.xmllib
     * 3. xml.sax.saxexts
          + 3.1 ExtendedParser methods
          + 3.2 ParserFactory methods
     * 4. xml.sax.saxlib
          + 4.1 AttributeList methods
          + 4.2 DocumentHandler methods
          + 4.3 DTDHandler methods
          + 4.4 EntityResolver methods
          + 4.5 ErrorHandler methods
          + 4.6 Locator methods
          + 4.7 Parser methods
          + 4.8 SAXException methods
          + 4.9 SAXParseException methods
     * 5. xml.sax.saxutils
          + 5.1 Location methods
     * 6. xml.utils.iso8601 24 
       
                              1. xml.arch.xmlarch
                                       
   The xmlarch module contains an XML architectural forms processor
   written in Python. It allows you to process XML architectural forms
   using any parser that uses the SAX interfaces. The module allows you
   to process several architectures in one parsing pass. Architectural
   document events for an architecture can even be broadcasted to
   multiple DocumentHandlers. (e.g. you can have 2 handlers for the RDF
   architecture, 3 for the XLink architecture and perhaps one for the
   HyTime architecture.) The architecture processor uses the SAX
   DocumentHandler interface which means that you can register the
   architecture handler (ArchDocHandler) with any SAX 1.0 compliant
   parser. It currently does not process any meta document type
   definition documents (meta-DTDs). When a DTD parser module is
   available the code will be modified to use that in order to process
   meta-DTD information. Please note that validating and well-formed
   parsers may report different SAX events when parsing documents.
   
   The xmlarch module contains six classes: ArchDocHandler, Architecture,
   ArchParseState, ArchException, AttributeParser and Normalizer.
   
     * ArchDocHandler is a subclass of the saxlib.DocumentHandler
       interface. This is the class used for processing an architectural
       document.
     * Architecture contains information about an architecture.
     * ArchParseState holds information about an architecture's parse
       state when parsing a document.
     * AttributeParser parses architecture use declaration PIs (attribute
       strings).
     * ArchException holds information about an architectural exception
       thrown by an ArchDocHandler instance.
     * Normalizer is a document handler that outputs "normalized" XML.
       
1.1 ArchDocHandler methods

   Still undocumented.
   
1.2 Architecture methods

   Still undocumented.
   
1.3 ArchParseState methods

   Still undocumented.
   
1.4 ArchException methods

   Still undocumented.
   
1.5 AttributeParser methods

   Still undocumented.
   
1.6 Normalizer methods

   Still undocumented.
   
                             2. xml.parsers.xmllib
                                       
   This is a version of the xmllib module from Python 1.5, modified to
   use the _sgmlop C extension when it's available. This produces a
   significant speedup, amounting to about a factor of 5. The interface
   is unchanged from the original xmllib module; consult the Python
   Library Reference documentation for that module.
   
                              3. xml.sax.saxexts
                                       
   make_parser ([parser])
          A utility function that returns a Parser object for a
          non-validating XML parser. If parser is specified, it must be a
          parser name; otherwise, a list of available parsers is checked
          and the fastest one chosen.
          
   HTMLParserFactory
          An instance of the ParserFactory class that's already been
          prepared with a list of HTML parsers. Simply call its
          make_parser() method to get a Parser object.
          
   ParserFactory ()
          A general class to be used by applications for creating parsers
          on foreign systems where the list of installed parsers is
          unknown.
          
   SGMLParserFactory
          An instance of the ParserFactory class that's already been
          prepared with a list of SGML parsers. Simply call its
          make_parser() method to get a parser object.
          
   XMLParserFactory
          An instance of the ParserFactory class that's already been
          prepared with a list of nonvalidating XML parsers. Simply call
          its make_parser() method to get a parser object.
          
   XMLValParserFactory
          An instance of the ParserFactory class that's already been
          prepared with a list of validating XML parsers. Simply call its
          make_parser() method to get a parser object.
          
   ExtendedParser ()
          This class is an experimental extended parser interface, that
          offers additional functionality that may be useful. However,
          it's not specified by the SAX specification.
          
3.1 ExtendedParser methods

   close ()
          Called after the last call to feed, when there are no more
          data.
          
   feed (data)
          Feeds data to the parser.
          
   get_parser_name ()
          Returns a single-word parser name.
          
   get_parser_version ()
          Returns the version of the imported parser, which may not be
          the one the driver was implemented for.
          
   is_dtd_reading ()
          True if the parser is non-validating, but conforms to the XML
          specification by reading the DTD.
          
   is_validating ()
          Returns true if the parser is validating, false otherwise.
          
   reset ()
          Makes the parser start parsing afresh.
          
3.2 ParserFactory methods

   get_parser_list ()
          Returns the list of possible drivers. Currently this starts out
          as ["xml.sax.drivers.drv_xmltok",
          "xml.sax.drivers.drv_xmlproc",
          "xml.sax.drivers.drv_xmltoolkit",
          "xml.sax.drivers.drv_xmllib"].
          
   make_parser ([driver_name])
          Returns a SAX driver for the first available parser of the
          parsers in the list. Note that the list contains drivers, so it
          first tries the driver and if that exists imports it to see if
          the parser also exists. If no parsers are available a
          SAXException is thrown.
          
          Optionally, driver_name can be a string containing the name of
          the driver to be used; the stored parser list will then not be
          used at all.
          
   set_parser_list (list)
          Sets the driver list to list.
          
                               4. xml.sax.saxlib
                                       
   AttributeList ()
          Interface for an attribute list. This interface provides
          information about a list of attributes for an element (only
          specified or defaulted attributes will be reported). Note that
          the information returned by this object will be valid only
          during the scope of the DocumentHandler.startElement callback,
          and the attributes will not necessarily be provided in the
          order declared or specified.
          
   DocumentHandler ()
          Handle general document events. This is the main client
          interface for SAX: it contains callbacks for the most important
          document events, such as the start and end of elements. You
          need to create an object that implements this interface, and
          then register it with the Parser. If you do not want to
          implement the entire interface, you can derive a class from
          HandlerBase, which implements the default functionality. You
          can find the location of any document event using the Locator
          interface supplied by setDocumentLocator().
          
   DTDHandler ()
          Handle DTD events. This interface specifies only those DTD
          events required for basic parsing (unparsed entities and
          attributes). If you do not want to implement the entire
          interface, you can extend HandlerBase, which implements the
          default behaviour.
          
   EntityResolver ()
          This is the basic interface for resolving entities. If you
          create an object implementing this interface, then register the
          object with your Parser instance, the parser will call the
          method in your object to resolve all external entities. Note
          that HandlerBase implements this interface with the default
          behaviour.
          
   ErrorHandler ()
          This is the basic interface for SAX error handlers. If you
          create an object that implements this interface, then register
          the object with your Parser, the parser will call the methods
          in your object to report all warnings and errors. There are
          three levels of errors available: warnings, (possibly)
          recoverable errors, and unrecoverable errors. All methods take
          a SAXParseException as the only parameter.
          
   HandlerBase ()
          Default base class for handlers. This class implements the
          default behaviour for four SAX interfaces, inheriting from them
          all: EntityResolver, DTDHandler, DocumentHandler, and
          ErrorHandler. Rather than implementing those full interfaces,
          you may simply extend this class and override the methods that
          you need. Note that the use of this class is optional, since
          you are free to implement the interfaces directly if you wish.
          
   Locator ()
          Interface for associating a SAX event with a document location.
          A locator object will return valid results only during calls to
          methods of the SAXDocumentHandler class; at any other time, the
          results are unpredictable.
          
   Parser ()
          Basic interface for SAX parsers. All SAX parsers must implement
          this basic interface: it allows users to register handlers for
          different types of events and to initiate a parse from a URI, a
          character stream, or a byte stream. SAX parsers should also
          implement a zero-argument constructor.
          
   SAXException (msg, exception, locator)
          Encapsulate an XML error or warning. This class can contain
          basic error or warning information from either the XML parser
          or the application: you can subclass it to provide additional
          functionality, or to add localization. Note that although you
          will receive a SAXException as the argument to the handlers in
          the ErrorHandler interface, you are not actually required to
          throw the exception; instead, you can simply read the
          information in it.
          
   SAXParseException (msg, exception, locator)
          Encapsulate an XML parse error or warning. This exception will
          include information for locating the error in the original XML
          document. Note that although the application will receive a
          SAXParseException as the argument to the handlers in the
          ErrorHandler interface, the application is not actually
          required to throw the exception; instead, it can simply read
          the information in it and take a different action.
          
          Since this exception is a subclass of SAXException, it inherits
          the ability to wrap another exception.
          
4.1 AttributeList methods

   The AttributeList class supports some of the behaviour of Python
   dictionaries; the len(), has_key(), keys() methods are available, and
   attr['href'] will retrieve the value of the href attribute. There are
   also additional methods specific to AttributeList:
   
   getLength ()
          Return the number of attributes in the list.
          
   getName (i)
          Return the name of attribute i in the list.
          
   getType (i)
          Return the type of an attribute in the list. i can be either
          the integer index or the attribute name.
          
   getValue (i)
          Return the value of an attribute in the list. i can be either
          the integer index or the attribute name.
          
4.2 DocumentHandler methods

   characters (ch, start, length)
          Handle a character data event.
          
   endDocument ()
          Handle an event for the end of a document.
          
   endElement (name)
          Handle an event for the end of an element.
          
   ignorableWhitespace (ch, start, length)
          Handle an event for ignorable whitespace in element content.
          
   processingInstruction (target, data)
          Handle a processing instruction event.
          
   setDocumentLocator (locator)
          Receive an object for locating the origin of SAX document
          events. You'll probably want to store the value of locator as
          an attribute of the handler instance.
          
   startDocument ()
          Handle an event for the beginning of a document.
          
   startElement (name, attrs)
          Handle an event for the beginning of an element.
          
4.3 DTDHandler methods

   notationDecl (name, publicId, systemId)
          Handle a notation declaration event.
          
   unparsedEntityDecl (publicId, systemId, notationName)
          Handle an unparsed entity declaration event.
          
4.4 EntityResolver methods

   resolveEntity (name, publicId, systemId)
          Resolve the system identifier of an entity.
          
4.5 ErrorHandler methods

   error (exception)
          Handle a recoverable error.
          
   fatalError (exception)
          Handle a non-recoverable error.
          
   warning (exception)
          Handle a warning.
          
4.6 Locator methods

   getColumnNumber ()
          Return the column number where the current event ends.
          
   getLineNumber ()
          Return the line number where the current event ends.
          
   getPublicId ()
          Return the public identifier for the current event.
          
   getSystemId ()
          Return the system identifier for the current event.
          
4.7 Parser methods

   parse (systemId)
          Parse an XML document from a system identifier.
          
   parseFile (fileobj)
          Parse an XML document from a file-like object.
          
   setDocumentHandler (handler)
          Register an object to receive basic document-related events.
          
   setDTDHandler (handler)
          Register an object to receive basic DTD-related events.
          
   setEntityResolver (resolver)
          Register an object to resolve external entities.
          
   setErrorHandler (handler)
          Register an object to receive error-message events.
          
   setLocale (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.
          
4.8 SAXException methods

   getException ()
          Return the embedded exception, if any.
          
   getMessage ()
          Return a message for this exception.
          
4.9 SAXParseException methods

   The SAXParseException class has a locator attribute, containing an
   instance of the Locator class, which represents the location in the
   document where the parse error occurred. The following methods are
   delegated to this instance.
   
   getColumnNumber ()
          Return the column number of the end of the text where the
          exception occurred.
          
   getLineNumber ()
          Return the line number of the end of the text where the
          exception occurred.
          
   getPublicId ()
          Return the public identifier of the entity where the exception
          occurred.
          
   getSystemId ()
          Return the system identifier of the entity where the exception
          occurred.
          
                              5. xml.sax.saxutils
                                       
   Canonizer (writer)
          A SAX document handler that produces canonicalized XML output.
          writer must support a write() method which accepts a single
          string.
          
   ErrorPrinter ()
          A simple class that just prints error messages to standard
          error (sys.stderr).
          
   ESISDocHandler (writer)
          A SAX document handler that produces naive ESIS output. writer
          must support a write() method which accepts a single string.
          
   EventBroadcaster (list)
          Takes a list of objects and forwards any method calls received
          to all objects in the list. The attribute list holds the list
          and can freely be modified by clients.
          
   Location (locator)
          Represents a location in an XML entity. Initialized by being
          passed a locator, from which it reads off the current location,
          which is then stored internally.
          
5.1 Location methods

   getColumnNumber ()
          Return the column number of the location.
          
   getLineNumber ()
          Return the line number of the location.
          
   getPublicId ()
          Return the public identifier for the location.
          
   getSystemId ()
          Return the system identifier for the location.
          
                             6. xml.utils.iso8601
                                       
   The xml.utils.iso8601 module provides conversion routines between the
   ISO 8601 representations of date/time values and the floating point
   values used elsewhere in Python. The floating point represtentation is
   particularly useful in conjunction with the standard time module.
   
   Currently, this module supports a small superset of the ISO 8601
   profile described by the World Wide Web Consortium (W3C). This is a
   subset of ISO 8601, but covers the cases expected to be used most
   often in the context of XML processing and Web applications. Future
   versions of this module may support a larger subset of
   ISO 8601-defined formats.
   
   parse (s)
          Parse an ISO 8601 date representation (with an optional
          time-of-day component) and return the date in seconds since the
          epoch.
          
   parse_timezone (timezone)
          Parse an ISO 8601 time zone designator and return the offset
          relative to Universal Coordinated Time (UTC) in seconds. If
          timezone is not valid, ValueError is raised.
          
   tostring (t[, timezone])
          Return formatted date/time value according to the profile
          described by the W3C. If timezone is provided, it must be the
          offset from UTC in seconds specified as a number, or time zone
          designator which can be parsed by parse_timezone(). If timezone
          is specified as a string and cannot be parsed by
          parse_timezone(), ValueError will be raised.
          
   ctime (t)
          Return formatter date/time value using the local timezone. This
          is equivalent to "tostring(t, time.timezone)".
          
   See Also:
   
   International Organization for Standardization. Data elements and
   interchange formats -- Information interchange -- Representation of
   dates and times. International Organization for Standardization, 1988.
   
   Gary Houston. ISO 8601 date/time representations. January 1993.
   Available online as compressed PostScript:
   ftp://ftp.informatik.uni-erlangen.de/pub/doc/ISO/ISO8601.ps.Z.
   
   Markus Kuhn. A Summary of the International Standard Dateand Time
   Notation. Available online at
   http://www.cl.cam.ac.uk/~mgk25/iso-time.html.
   
   Misha Wolf and Charles Wicksteed. Date and Time Formats. World Wide
   Web Consortium Technical Note, September 1998. Available online at
   http://www.w3.org/TR/NOTE-datetime.
   
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   Python/XML Reference Guide
   
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   Python/XML Reference Guide
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