1  """Simple API for XML (SAX) implementation for Python.
       2  
       3  This module provides an implementation of the SAX 2 interface;
       4  information about the Java version of the interface can be found at
       5  http://www.megginson.com/SAX/.  The Python version of the interface is
       6  documented at <...>.
       7  
       8  This package contains the following modules:
       9  
      10  handler -- Base classes and constants which define the SAX 2 API for
      11             the 'client-side' of SAX for Python.
      12  
      13  saxutils -- Implementation of the convenience classes commonly used to
      14              work with SAX.
      15  
      16  xmlreader -- Base classes and constants which define the SAX 2 API for
      17               the parsers used with SAX for Python.
      18  
      19  expatreader -- Driver that allows use of the Expat parser with SAX.
      20  """
      21  
      22  from .xmlreader import InputSource
      23  from .handler import ContentHandler, ErrorHandler
      24  from ._exceptions import SAXException, SAXNotRecognizedException, \
      25                          SAXParseException, SAXNotSupportedException, \
      26                          SAXReaderNotAvailable
      27  
      28  
      29  def parse(source, handler, errorHandler=ErrorHandler()):
      30      parser = make_parser()
      31      parser.setContentHandler(handler)
      32      parser.setErrorHandler(errorHandler)
      33      parser.parse(source)
      34  
      35  def parseString(string, handler, errorHandler=ErrorHandler()):
      36      import io
      37      if errorHandler is None:
      38          errorHandler = ErrorHandler()
      39      parser = make_parser()
      40      parser.setContentHandler(handler)
      41      parser.setErrorHandler(errorHandler)
      42  
      43      inpsrc = InputSource()
      44      if isinstance(string, str):
      45          inpsrc.setCharacterStream(io.StringIO(string))
      46      else:
      47          inpsrc.setByteStream(io.BytesIO(string))
      48      parser.parse(inpsrc)
      49  
      50  # this is the parser list used by the make_parser function if no
      51  # alternatives are given as parameters to the function
      52  
      53  default_parser_list = ["xml.sax.expatreader"]
      54  
      55  # tell modulefinder that importing sax potentially imports expatreader
      56  _false = 0
      57  if _false:
      58      import xml.sax.expatreader
      59  
      60  import os, sys
      61  if not sys.flags.ignore_environment and "PY_SAX_PARSER" in os.environ:
      62      default_parser_list = os.environ["PY_SAX_PARSER"].split(",")
      63  del os, sys
      64  
      65  
      66  def make_parser(parser_list=()):
      67      """Creates and returns a SAX parser.
      68  
      69      Creates the first parser it is able to instantiate of the ones
      70      given in the iterable created by chaining parser_list and
      71      default_parser_list.  The iterables must contain the names of Python
      72      modules containing both a SAX parser and a create_parser function."""
      73  
      74      for parser_name in list(parser_list) + default_parser_list:
      75          try:
      76              return _create_parser(parser_name)
      77          except ImportError:
      78              import sys
      79              if parser_name in sys.modules:
      80                  # The parser module was found, but importing it
      81                  # failed unexpectedly, pass this exception through
      82                  raise
      83          except SAXReaderNotAvailable:
      84              # The parser module detected that it won't work properly,
      85              # so try the next one
      86              pass
      87  
      88      raise SAXReaderNotAvailable("No parsers found", None)
      89  
      90  # --- Internal utility methods used by make_parser
      91  
      92  def _create_parser(parser_name):
      93      drv_module = __import__(parser_name,{},{},['create_parser'])
      94      return drv_module.create_parser()