rosjson.py
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00001 #!/usr/bin/env python
00002 # Software License Agreement (BSD License)
00003 #
00004 # Copyright (c) 2009, Willow Garage, Inc.
00005 # All rights reserved.
00006 #
00007 # Redistribution and use in source and binary forms, with or without
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00010 #
00011 #  * Redistributions of source code must retain the above copyright
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00013 #  * Redistributions in binary form must reproduce the above
00014 #    copyright notice, this list of conditions and the following
00015 #    disclaimer in the documentation and/or other materials provided
00016 #    with the distribution.
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00021 # THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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00034 # Revision $Id: rosweb.py 4149 2009-04-13 17:00:09Z sfkwc $
00035 
00036 import roslib; roslib.load_manifest('rosjson')
00037 
00038 import cStringIO
00039 import os
00040 
00041 import rospy
00042 import genpy
00043 
00044 class ROSJSONException(rospy.ROSException): pass
00045 
00046 _JSON_ESCAPE = {'\\':r'\\', '"':'\\"', '\b':r'\b', '\f':r'\f', '\n':r'\n', '\r':r'\r', '\t':r'\t'}
00047 
00048 ## Convert value to JSON representation
00049 ## @param v Any: value to convert to JSON. Supported types are Python primitives (str, int, float, long, bool) as well as rospy Message-related types (Message, Time, Duration).
00050 ## @return str: JSON string representation of \a v
00051 ## @throws ROSJSONException if \a msg cannot be converted to JSON
00052 def value_to_json(v):
00053     if type(v) == str:
00054         buff = cStringIO.StringIO()
00055         
00056         buff.write('"')
00057         for c in v:
00058             if c in _JSON_ESCAPE:
00059                 buff.write(_JSON_ESCAPE[c])
00060             else:
00061                 buff.write(c)
00062         buff.write('"')                
00063 
00064         return buff.getvalue()
00065     elif type(v) in (int, float, long):
00066         return "%s"%v
00067     elif type(v) in (list, tuple):
00068         return '['+','.join([value_to_json(x) for x in v]) + ']'
00069     elif type(v) == bool:
00070         if v:
00071             return 'true'
00072         else:
00073             return 'false'
00074     elif isinstance(v, rospy.Message):
00075         return ros_message_to_json(v)
00076     elif isinstance(v, (genpy.rostime.Time, genpy.rostime.Duration)):
00077         return v.to_sec()
00078     else:
00079         raise ROSJSONException("unknown type: %s"%type(v))
00080         
00081 ## Convert ROS message to JSON representation. JSON representation is
00082 ## a simple dictionary of dictionaries, where a dictionary represents
00083 ## a ROS message. Time and duration are represented by their float value
00084 ## in seconds.
00085 ##
00086 ## @param msg rospy.Message: message instance to convert
00087 ## @throws ROSJSONException if \a msg cannot be converted to JSON
00088 def ros_message_to_json(msg):
00089     if not isinstance(msg, rospy.Message):
00090         raise ROSJSONException("not a valid rospy Message instance: %s"%msg.__class__.__name__)
00091     buff = cStringIO.StringIO()
00092     buff.write('{')
00093     buff.write(','.join(['"%s": %s'%(f, value_to_json(getattr(msg, f))) for f in msg.__slots__]))
00094     buff.write('}')
00095     return buff.getvalue()


rosjson
Author(s): Ken Conley/kwc@willowgarage.com
autogenerated on Wed Apr 23 2014 10:35:53