"""
import simplejson
-import ConfigParser
import re
+import hmac
+
+from ganeti import errors
-# Check whether the simplejson module supports indentation
-_JSON_INDENT = 2
try:
- simplejson.dumps(1, indent=_JSON_INDENT)
-except TypeError:
- _JSON_INDENT = None
+ from hashlib import sha1
+except ImportError:
+ import sha as sha1
+
+
+_JSON_INDENT = 2
+
+_RE_EOLSP = re.compile('[ \t]+$', re.MULTILINE)
+
+
+def _GetJsonDumpers():
+ """Returns two JSON functions to serialize data.
+
+ @rtype: (callable, callable)
+ @return: The function to generate a compact form of JSON and another one to
+ generate a more readable, indented form of JSON (if supported)
-_RE_EOLSP = re.compile('\s+$', re.MULTILINE)
+ """
+ plain_dump = simplejson.dumps
+
+ # Check whether the simplejson module supports indentation
+ try:
+ simplejson.dumps(1, indent=_JSON_INDENT)
+ except TypeError:
+ # Indentation not supported
+ indent_dump = plain_dump
+ else:
+ # Indentation supported
+ indent_dump = lambda data: simplejson.dumps(data, indent=_JSON_INDENT)
+
+ assert callable(plain_dump)
+ assert callable(indent_dump)
+
+ return (plain_dump, indent_dump)
-def Dump(data):
+(_DumpJson, _DumpJsonIndent) = _GetJsonDumpers()
+
+
+def DumpJson(data, indent=True):
"""Serialize a given object.
+ @param data: the data to serialize
+ @param indent: whether to indent output (depends on simplejson version)
+
+ @return: the string representation of data
+
"""
- if _JSON_INDENT is None:
- txt = simplejson.dumps(data)
+ if indent:
+ fn = _DumpJsonIndent
else:
- txt = simplejson.dumps(data, indent=_JSON_INDENT)
+ fn = _DumpJson
+
+ txt = _RE_EOLSP.sub("", fn(data))
if not txt.endswith('\n'):
txt += '\n'
- txt = _RE_EOLSP.sub("", txt)
+
return txt
-def Load(txt):
+def LoadJson(txt):
"""Unserialize data from a string.
+ @param txt: the json-encoded form
+
+ @return: the original data
+
"""
return simplejson.loads(txt)
+
+
+def DumpSignedJson(data, key, salt=None):
+ """Serialize a given object and authenticate it.
+
+ @param data: the data to serialize
+ @param key: shared hmac key
+ @return: the string representation of data signed by the hmac key
+
+ """
+ txt = DumpJson(data, indent=False)
+ if salt is None:
+ salt = ''
+ signed_dict = {
+ 'msg': txt,
+ 'salt': salt,
+ 'hmac': hmac.new(key, salt + txt, sha1).hexdigest(),
+ }
+ return DumpJson(signed_dict, indent=False)
+
+
+def LoadSignedJson(txt, key):
+ """Verify that a given message was signed with the given key, and load it.
+
+ @param txt: json-encoded hmac-signed message
+ @param key: shared hmac key
+ @rtype: tuple of original data, string
+ @return: original data, salt
+ @raises errors.SignatureError: if the message signature doesn't verify
+
+ """
+ signed_dict = LoadJson(txt)
+ if not isinstance(signed_dict, dict):
+ raise errors.SignatureError('Invalid external message')
+ try:
+ msg = signed_dict['msg']
+ salt = signed_dict['salt']
+ hmac_sign = signed_dict['hmac']
+ except KeyError:
+ raise errors.SignatureError('Invalid external message')
+
+ if hmac.new(key, salt + msg, sha1).hexdigest() != hmac_sign:
+ raise errors.SignatureError('Invalid Signature')
+
+ return LoadJson(msg), salt
+
+
+Dump = DumpJson
+Load = LoadJson
+DumpSigned = DumpSignedJson
+LoadSigned = LoadSignedJson