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- """Wraps the best available JSON implementation available in a common
- interface"""
-
- import sys
-
- VERSION = (0, 3, 3)
- __version__ = ".".join(map(str, VERSION[0:3])) + "".join(VERSION[3:])
- __author__ = "Rune Halvorsen"
- __contact__ = "runefh@gmail.com"
- __homepage__ = "http://bitbucket.org/runeh/anyjson/"
- __docformat__ = "restructuredtext"
-
- # -eof meta-
-
- #: The json implementation object. This is probably not useful to you,
- #: except to get the name of the implementation in use. The name is
- #: available through ``implementation.name``.
- implementation = None
-
- # json.loads does not support buffer() objects,
- # so we load() and StringIO instead, and it won't copy.
- if sys.version_info[0] == 3:
- from io import StringIO
- else:
- try:
- from io import StringIO # noqa
- except ImportError:
- from io import StringIO # noqa
-
- #: List of known json modules, and the names of their loads/dumps
- #: methods, as well as the exceptions they throw. Exception can be either
- #: an exception class or a string.
- _modules = [("yajl", "dumps", TypeError, "loads", ValueError, "load"),
- ("jsonlib2", "write", "WriteError", "read", "ReadError", None),
- ("jsonlib", "write", "WriteError", "read", "ReadError", None),
- ("simplejson", "dumps", TypeError, "loads", ValueError, "load"),
- ("json", "dumps", TypeError, "loads", ValueError, "load"),
- ("django.utils.simplejson", "dumps", TypeError, "loads", ValueError, "load"),
- ("cjson", "encode", "EncodeError", "decode", "DecodeError", None)
- ]
-
- _fields = ("modname", "encoder", "encerror",
- "decoder", "decerror", "filedecoder")
-
-
- class _JsonImplementation(object):
- """Incapsulates a JSON implementation"""
-
- def __init__(self, modspec):
- modinfo = dict(list(zip(_fields, modspec)))
-
- if modinfo["modname"] == "cjson":
- import warnings
- warnings.warn("cjson is deprecated! See http://pypi.python.org/pypi/python-cjson/1.0.5", DeprecationWarning)
-
- # No try block. We want importerror to end up at caller
- module = self._attempt_load(modinfo["modname"])
-
- self.implementation = modinfo["modname"]
- self._encode = getattr(module, modinfo["encoder"])
- self._decode = getattr(module, modinfo["decoder"])
- fdec = modinfo["filedecoder"]
- self._filedecode = fdec and getattr(module, fdec)
- self._encode_error = modinfo["encerror"]
- self._decode_error = modinfo["decerror"]
-
- if isinstance(modinfo["encerror"], str):
- self._encode_error = getattr(module, modinfo["encerror"])
- if isinstance(modinfo["decerror"], str):
- self._decode_error = getattr(module, modinfo["decerror"])
-
- self.name = modinfo["modname"]
-
- def __repr__(self):
- return "<_JsonImplementation instance using %s>" % self.name
-
- def _attempt_load(self, modname):
- """Attempt to load module name modname, returning it on success,
- throwing ImportError if module couldn't be imported"""
- __import__(modname)
- return sys.modules[modname]
-
- def dumps(self, data):
- """Serialize the datastructure to json. Returns a string. Raises
- TypeError if the object could not be serialized."""
- try:
- return self._encode(data)
- except self._encode_error as exc:
- raise TypeError(TypeError(*exc.args)).with_traceback(sys.exc_info()[2])
- serialize = dumps
-
- def loads(self, s):
- """deserialize the string to python data types. Raises
- ValueError if the string could not be parsed."""
- # uses StringIO to support buffer objects.
- try:
- if self._filedecode and not isinstance(s, str):
- return self._filedecode(StringIO(s))
- return self._decode(s)
- except self._decode_error as exc:
- raise ValueError(ValueError(*exc.args)).with_traceback(sys.exc_info()[2])
- deserialize = loads
-
-
- def force_implementation(modname):
- """Forces anyjson to use a specific json module if it's available"""
- global implementation
- for name, spec in [(e[0], e) for e in _modules]:
- if name == modname:
- implementation = _JsonImplementation(spec)
- return
- raise ImportError("No module named: %s" % modname)
-
-
- if __name__ == "__main__":
- # If run as a script, we do nothing but print an error message.
- # We do NOT try to load a compatible module because that may throw an
- # exception, which renders the package uninstallable with easy_install
- # (It trys to execfile the script when installing, to make sure it works)
- print("Running anyjson as a stand alone script is not supported")
- sys.exit(1)
- else:
- for modspec in _modules:
- try:
- implementation = _JsonImplementation(modspec)
- break
- except ImportError:
- pass
- else:
- raise ImportError("No supported JSON module found")
-
-
- def loads(value):
- """Serialize the object to JSON."""
- return implementation.loads(value)
- deserialize = loads # compat
-
-
- def dumps(value):
- """Deserialize JSON-encoded object to a Python object."""
- return implementation.dumps(value)
- serialize = dumps
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