Source Code for Module wtf.ext.db._tagged

  1  # -*- coding: ascii -*- 
  2  # 
  3  # Copyright 2010-2012 
  4  # Andr\xe9 Malo or his licensors, as applicable 
  5  # 
  6  # Licensed under the Apache License, Version 2.0 (the "License"); 
  7  # you may not use this file except in compliance with the License. 
  8  # You may obtain a copy of the License at 
  9  # 
 10  #     http://www.apache.org/licenses/LICENSE-2.0 
 11  # 
 12  # Unless required by applicable law or agreed to in writing, software 
 13  # distributed under the License is distributed on an "AS IS" BASIS, 
 14  # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 
 15  # See the License for the specific language governing permissions and 
 16  # limitations under the License. 
 17  """ 
 18  ============================ 
 19   Tagged connection creation 
 20  ============================ 
 21   
 22  Tagged connection creation. 
 23  """ 
 24  __author__ = u"Andr\xe9 Malo" 
 25  __docformat__ = "restructuredtext en" 
 26   
 27  from wtf.ext.db import _connection 
 28  from wtf.ext.db import _decorators 
 29   
 30   
 31  #: Global tag mapping 
 32  #: 
 33  #: :Type: ``dict`` 
 34  _connection_tags = {} 
 35   
 36   
 37 -def dbname(tag): 
 38      """ 
 39      Determine dbname from tag 
 40   
 41      :Parameters: 
 42        `tag` : ``str`` 
 43          Connection tag 
 44   
 45      :Return: DB name 
 46      :Rtype: ``str`` 
 47      """ 
 48      return _connection_tags[tag] 
 49   
 50   
 51 -def driver(tag): 
 52      """ 
 53      Determine driver module 
 54   
 55      :Parameters: 
 56        `tag` : ``str`` 
 57          Connection tag 
 58   
 59      :Return: Driver module 
 60      :Rtype: ``module`` 
 61   
 62      :Exceptions: 
 63        - `DBConfigurationError` : DB not configured 
 64        - `KeyError` : DB name not found 
 65        - `ImportError` : Driver not found 
 66      """ 
 67      return _connection.driver(dbname(tag)) 
 68   
 69   
 70 -def connect(tag, **kwargs): 
 71      """ 
 72      Connect and create a connection 
 73   
 74      :Parameters: 
 75        `tag` : ``str`` 
 76          Connection tag 
 77   
 78      :Return: connection 
 79      :Rtype: ``Connection`` 
 80      """ 
 81      return _connection.connect(dbname(tag), **kwargs) 
 82   
 83   
 84 -def connection(tag, arg=None, translate_exceptions=True): 
 85      """ 
 86      Create decorator to inject connection into function 
 87   
 88      :Parameters: 
 89        `tag` : ``str`` 
 90          Connection tag 
 91   
 92        `arg` : ``str`` 
 93          Argument name. If omitted or ``None``, ``'db'`` is used. 
 94   
 95        `translate_exceptions` : ``bool`` 
 96          Translate adapter exceptions to our ones? 
 97   
 98      :Return: Decorator function 
 99      :Rtype: ``callable`` 
100      """ 
101      return _decorators.connection(dbname(tag), arg, translate_exceptions) 
102   
103   
104 -def transaction(arg=None): 
105      """ 
106      Create decorator to wrap a connection into a transaction 
107   
108      :Parameters: 
109        `arg` : ``str`` 
110          Argument name. If omitted or ``None``, ``'db'`` is used. 
111   
112      :Return: Decorator function 
113      :Rtype: ``callable`` 
114      """ 
115      return _decorators.transaction(arg) 
116   
117   
118 -def register_connection_tag(tag, dbname): 
119      """ 
120      Register a connection tag 
121   
122      :Parameters: 
123        `tag` : ``str`` 
124          Tag name 
125   
126        `dbname` : ``str`` 
127          DB name string 
128   
129      :Exceptions: 
130        - `ValueError` : Tag already defined with a different value 
131      """ 
132      # pylint: disable = W0621 
133      if tag in _connection_tags and _connection_tags[tag] != dbname: 
134          raise ValueError("Tag %r (=%r) redefined as %r" % ( 
135              tag, _connection_tags[tag], dbname 
136          )) 
137      _connection_tags[tag] = dbname 
138