Source Code for Module glue.segmentdb.query_engine

  1  # 
  2  # Copyright (C) 2009  Larne Pekowsky 
  3  # 
  4  # This program is free software; you can redistribute it and/or modify it 
  5  # under the terms of the GNU General Public License as published by the 
  6  # Free Software Foundation; either version 3 of the License, or (at your 
  7  # option) any later version. 
  8  # 
  9  # This program is distributed in the hope that it will be useful, but 
 10  # WITHOUT ANY WARRANTY; without even the implied warranty of 
 11  # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General 
 12  # Public License for more details. 
 13  # 
 14  # You should have received a copy of the GNU General Public License along 
 15  # with this program; if not, write to the Free Software Foundation, Inc., 
 16  # 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA. 
 17   
 18   
 19  # 
 20  # ============================================================================= 
 21  # 
 22  #                                  Preamble 
 23  # 
 24  # ============================================================================= 
 25  # 
 26   
 27   
 28  """ 
 29  Provides a unified interface for querying sqlite databases and a DB2 database 
 30  behind a ldbd interface 
 31  """ 
 32   
 33  import os 
 34  try: 
 35      import pyRXP 
 36  except ImportError: 
 37      import pyRXPU as pyRXP 
 38  from glue import ldbd 
 39   
 40  from glue import git_version 
 41  __date__ = git_version.date 
 42  __version__ = git_version.id 
 43  __author__  = "Larne Pekowsky <lppekows@physics.syr.edu>" 
 44   
 45   
 46 -class QueryEngine: 
 47          """Abstract class.  Provides query() method that returns something that 
 48          behaves like an array of tuples of results and a close() method that 
 49          does any needed cleanup.""" 
 50   
 51 -        def query(sql): 
 52                  return None 
 53   
 54 -        def close(): 
 55                  pass 
 56   
 57   
 58 -class SqliteQueryEngine(QueryEngine): 
 59          """QueryEngine for sqlite databases.  Really just a minimal wrapper 
 60          around cursor""" 
 61   
 62          connection = None 
 63          cursor     = None 
 64   
 65 -        def __init__(self, connection): 
 66                  self.connection = connection 
 67           
 68 -        def query(self, sql): 
 69                  self.cursor = self.connection.cursor().execute(sql) 
 70                  ret         = [] 
 71   
 72                  for row in self.cursor: 
 73                          ret.append(row) 
 74   
 75                  return ret 
 76   
 77 -        def close(self): 
 78                  self.cursor.close() 
 79                  del self.cursor 
 80   
 81   
 82 -class LdbdQueryEngine(QueryEngine): 
 83          """QueryEngine for databses behind ldbd.  Parses ligolw that a query 
 84          returns into rows""" 
 85   
 86          xmlparser = None 
 87          lwtparser = None 
 88          ligomd    = None 
 89   
 90          rows      = None 
 91           
 92   
 93   
 94 -        def __init__(self, client): 
 95                  def dtd_uri_callback(uri): 
 96                          if uri == 'http://ldas-sw.ligo.caltech.edu/doc/ligolwAPI/html/ligolw_dtd.txt': 
 97                                  return 'file://localhost' + os.path.join( os.environ["GLUE_PREFIX"], 'etc/ligolw_dtd.txt' ) 
 98                          else: 
 99                                  return uri 
100   
101                  self.client      = client 
102                  self.xmlparser      = pyRXP.Parser() 
103                  self.xmlparser.eoCB = dtd_uri_callback           
104                  self.lwtparser      = ldbd.LIGOLwParser() 
105                  self.ligomd      = ldbd.LIGOMetadata(self.xmlparser, self.lwtparser, None) 
106   
107   
108 -        def query(self, sql): 
109                  xml = self.client.query(sql) 
110                   
111                  # This is a kludge around bug 2317 
112                  try: 
113                          self.client.__disconnect__() 
114                          self.client.__connect__(self.client.host, self.client.port, self.client.identity) 
115                  except: 
116                          pass 
117    
118                  self.ligomd.parse(xml) 
119                  res = self.ligomd.table 
120                  self.rows = self.ligomd.table[list(res.keys())[0]]['stream'] 
121   
122                  return self.rows 
123           
124 -        def close(self): 
125                  del self.rows 
126