Source Code for Module rats.statesaving

 1  #!/usr/bin/env python 
 2  """ 
 3  State saving tools 
 4   
 5  Two json modules exist. We must use the simplejson that became  
 6  the standard json module in Python 2.6 
 7  """ 
 8  try: 
 9      import json # python 2.6 
10  except ImportError: 
11      import simplejson as json # python 2.4 to 2.5 
12  try: 
13      _tmp = json.loads 
14  except AttributeError: 
15      import warnings 
16      import sys 
17      warnings.warn("Use simplejson, not the old json module.") 
18      sys.modules.pop('json') # get rid of the bad json module 
19      import simplejson as json 
20   
21 -class StateSavingError(Exception): 
22      """ 
23      Any error the Saver class can generate. 
24      """ 
25      pass 
26   
27 -def save(file_name, data): 
28      """ 
29      State saving using JSON 
30   
31      The data attribute is a dict of basic types. 
32      (``str``, ``unicode``, ``int``, ``long``, ``float``, ``bool``, ``None``) 
33      It can contain dicts and lists as well. 
34      """ 
35      try: 
36          f = open(file_name, "w") 
37      except IOError, e: 
38          raise StateSavingError(e.message) 
39      json.dump(data, f, indent=4) 
40      f.close() 
41   
42 -def load(file_name): 
43      try: 
44          f = open(file_name, "r") 
45      except IOError, e: 
46          raise StateSavingError(e.message) 
47      data = json.load(f) 
48      f.close() 
49      return data 
50           
51  if __name__ == "__main__": 
52      import tempfile 
53      filename = tempfile.mktemp() 
54      print("Loading from %s" % (filename)) 
55      try: 
56          data = load(file_name) 
57      except StateSavingError, e: 
58          print(e.message) 
59          pass 
60      print("data: %s"  %(data)) 
61      data['x'] = 2 
62      data['y'] = 3.14159 
63      data['z'] = [1,2,3,4,5,6] 
64      data['a'] = {'egg':'white', 'ham':'pink'} 
65      print("data: %s"  %(data)) 
66      print("Saving to %s" % (file_name)) 
67      save(file_name, data) 
68