Source Code for Module rdfalchemy.Literal'

  1  #!/usr/bin/env python 
  2  # encoding: utf-8 
  3  """ 
  4  Literal.py 
  5   
  6  Created by Philip Cooper on 2008-02-09. 
  7  Copyright (c) 2008 Openvest. All rights reserved. 
  8  """ 
  9  from rdflib import Namespace, Literal 
 10  from rdflib.Literal import bind as bindLiteral 
 11  from rdflib.Literal import _PythonToXSD 
 12  import re 
 13  import logging 
 14   
 15  XSD = Namespace(u'http://www.w3.org/2001/XMLSchema#') 
 16   
 17  ################################################################################ 
 18  # Let's fix the logging.  This seems like a lot of work... 
 19  # all that it does is not log rebinding errors.  
 20  # We know already about them ... and the warnings confuse the citizenry. 
 21  _log = logging.getLogger("rdflib") 
 22  if not _log.handlers: 
 23 -    class rebindingLogFilter(logging.Filter): 
 24 -        def filter(self, record): 
 25              if record.getMessage().find("Rebinding") > -1: 
 26                  return False 
 27              return True 
 28       
 29      h = logging.StreamHandler() 
 30      h.addFilter(rebindingLogFilter()) 
 31      _log.addHandler(h) 
 32       
 33  ################################################################################ 
 34  ## Let's make toPython return a Decimal if an XSD.decimal in in the triplestore 
 35  try: 
 36      from decimal import Decimal 
 37      bindLiteral(XSD.decimal,Decimal) 
 38      _PythonToXSD.update(dict([(Decimal,(str,XSD.decimal))])) 
 39  except: 
 40      pass 
 41       
 42  ################################################################################ 
 43  ## Default behavior returns untyped literals as literals 
 44  ## this brings untyped literals back as unicode strings 
 45  bindLiteral(None,unicode) 
 46   
 47  ################################################################################ 
 48  ## Default behavior returns string literals as literals 
 49  ## this brings  string literals back as unicode strings 
 50  bindLiteral(XSD.string,unicode) 
 51           
 52  ################################################################################ 
 53  ## Let's make toPython return a datetime if the literal has fractional seconds 
 54  ## Note: dateparser adapted from http://www.mnot.net/python/isodate.py 
 55  ## modified to: handle fractional seconds beyond tenths  
 56  ##              and to allow pseudo iso i.e. "2001-12-15 22:43:46"  
 57  ##                                        vs "2001-12-15T22:43:46" 
 58  import datetime 
 59   
 60  date_parser = re.compile(r"""^ 
 61      (?P<year>\d{4}) 
 62      (?:- 
 63          (?P<month>\d{1,2}) 
 64          (?:- 
 65              (?P<day>\d{1,2}) 
 66              (?:[T ] 
 67                  (?P<hour>\d{1,2}) 
 68                  : 
 69                  (?P<minute>\d{1,2}) 
 70                  (?:: 
 71                      (?P<second>\d{1,2}) 
 72                      (?P<dec_second>\.\d+)? 
 73                  )?                     
 74                  (?:Z|(?: 
 75                          (?P<tz_sign>[+-]) 
 76                          (?P<tz_hour>\d{1,2}) 
 77                          :? 
 78                          (?P<tz_min>\d{2,2}) 
 79                       ) 
 80                  )? 
 81              )? 
 82          )? 
 83      )? 
 84  $""", re.VERBOSE) 
 85   
 86 -def _strToDateTime(s): 
 87          """ parse a string and return a datetime object. """ 
 88          assert isinstance(s, basestring) 
 89          r = date_parser.search(s) 
 90          try: 
 91              a = r.groupdict('0') 
 92          except: 
 93              raise ValueError, 'invalid date string format' 
 94               
 95          dt = datetime.datetime(int(a['year']), 
 96                                 int(a['month']) or 1, 
 97                                 int(a['day']) or 1, 
 98                                 # If not given these will default to 00:00:00.0 
 99                                 int(a['hour']), 
100                                 int(a['minute']), 
101                                 int(a['second']), 
102                                 # Convert into microseconds 
103                                 int(float(a['dec_second'])*1000000), 
104                                 ) 
105          tz_hours_offset = int(a['tz_hour']) 
106          tz_mins_offset = int(a['tz_min']) 
107          if a.get('tz_sign', '+') == "-": 
108              return dt + datetime.timedelta(hours = tz_hours_offset, 
109                                             minutes = tz_mins_offset) 
110          else: 
111              return dt - datetime.timedelta(hours = tz_hours_offset, 
112                                             minutes = tz_mins_offset) 
113   
114  bindLiteral(XSD.dateTime,_strToDateTime) 
115