Merge lp:~wallyworld/lazr.json/deserialisation-sometimes-fails-987043 into lp:lazr.json

[Ian Booth]

Ensure single value dicts are properly deserialised.

== Implementation ==

Tweak to deccoder to ensure that single value dicts are decoded properly. Previously, a single value dict would always be interpreted as an encoded object and attempts to deserialise it would result in failure.

== Tests ==

Add extra doc tests to README.txt

== Lint ==

Lint free apart from false positives.

[Ian Booth (wallyworld)]

Minor change, self reviewed.

review: Approve

=== modified file 'src/lazr/json/NEWS.txt'
--- src/lazr/json/NEWS.txt	2012-04-19 07:41:21 +0000
+++ src/lazr/json/NEWS.txt	2012-04-23 00:33:18 +0000
@@ -2,6 +2,11 @@
 NEWS for lazr.json
 =====================
 
+0.2 (2012-04-23)
+================
+
+- Fix issue with deserialising single value dicts (bug 987043)
+
 0.1 (2012-04-19)
 ================
 

=== modified file 'src/lazr/json/README.txt'
--- src/lazr/json/README.txt	2012-04-19 23:21:21 +0000
+++ src/lazr/json/README.txt	2012-04-23 00:33:18 +0000
@@ -69,7 +69,7 @@
 
     >>> register_serialisable_type("complex", ComplexObject)
     >>> print json.dumps(obj, cls=CustomTypeEncoder)
-    {"complex,__builtin__.ComplexObject":
+    {"%complex,__builtin__.ComplexObject%":
     {"f_int": 5, "f_string": "string_value"}}
 
 We can register an encoder for a complex object.
@@ -88,7 +88,7 @@
 The json encoding of the object is changed accordingly.
 
     >>> print json.dumps(obj, cls=CustomTypeEncoder)
-    {"complex,__builtin__.ComplexObject":
+    {"%complex,__builtin__.ComplexObject%":
     "{\"int_value\": 5, \"str_value\": \"string_value\"}"}
 
 Arbitrarily complex objects are supported, including those with complex
@@ -101,8 +101,8 @@
     >>> register_serialisable_type("another", AnotherComplexObject)
     >>> another = AnotherComplexObject()
     >>> print json.dumps(another, cls=CustomTypeEncoder)
-    {"another,__builtin__.AnotherComplexObject":
-    {"obj": {"complex,__builtin__.ComplexObject":
+    {"%another,__builtin__.AnotherComplexObject%":
+    {"obj": {"%complex,__builtin__.ComplexObject%":
     "{\"int_value\": 5, \"str_value\": \"string_value\"}"}}}
 
 Collections of complex objects can be serialised.
@@ -110,7 +110,7 @@
     >>> complex_collection = [ComplexObject() for x in range(4)]
     >>> json_collection = json.dumps(complex_collection, cls=CustomTypeEncoder)
     >>> print json_collection
-    [{"complex,__builtin__.ComplexObject":
+    [{"%complex,__builtin__.ComplexObject%":
     "{\"int_value\": 5, \"str_value\": \"string_value\"}"}, ...]
 
 ==========================
@@ -131,7 +131,7 @@
 
     >>> an_apple = Fruit.APPLE
     >>> print json.dumps(an_apple, cls=CustomTypeEncoder)
-    {"BaseItem,lazr.enum._enum.Item": "{\"type\": \"Fruit\", \"name\": \"APPLE\"}"}
+    {"%BaseItem,lazr.enum._enum.Item%": "{\"type\": \"Fruit\", \"name\": \"APPLE\"}"}
 
 
 ======================
@@ -200,6 +200,18 @@
     >>> print deserialised == obj
     True
 
+Single value dicts which look like (but are not) serialised objects are
+correctly handled.
+    >>> dict_val = json.loads('{"a": 123}', object_hook=custom_type_decoder)
+    >>> print dict_val
+    {u'a': 123}
+    >>> dict_val = json.loads('{"a,b": 123}', object_hook=custom_type_decoder)
+    >>> print dict_val
+    {u'a,b': 123}
+    >>> dict_val = json.loads('{"%a,b%": 123}', object_hook=custom_type_decoder)
+    >>> print dict_val
+    {u'%a,b%': 123}
+
 ============================
 Deserialising Built In Types
 ============================
@@ -225,4 +237,3 @@
 
    *
    docs/*
-

=== modified file 'src/lazr/json/_serialisation.py'
--- src/lazr/json/_serialisation.py	2012-04-19 23:21:21 +0000
+++ src/lazr/json/_serialisation.py	2012-04-23 00:33:18 +0000
@@ -41,7 +41,7 @@
     """A custom JSONEncoder class that knows how to encode custom objects.
 
     Custom objects are encoded as JSON object literals with a single key,
-    'type_name,full_classname' where:
+    '%type_name,full_classname%' where:
         type_name is the name key taken from _SERIALISATION_TYPES
         full_classname is the classname of the object being serialised
 
@@ -64,7 +64,7 @@
             if len(class_info) > 1:
                 encoder = class_info[1]
             if isinstance(obj, obj_type):
-                key = ('%s,%s.%s'
+                key = ('%%%s,%s.%s%%'
                        % (type_name, obj.__module__, obj.__class__.__name__))
                 if encoder is None:
                     encoded_value = obj.__dict__
@@ -102,11 +102,17 @@
     if len(json_dict) == 1:
         # Determine the type_name and classname.
         classname_info, json_value = json_dict.items()[0]
-        type_name, specific_obj_classname = classname_info.split(',')
-        # If no registered decoder, return the raw value.
+        if (classname_info.find(',') < 0
+            or not classname_info.startswith('%')
+            or not classname_info.endswith('%')):
+            return json_dict
+        type_name, specific_obj_classname = (
+            classname_info.strip('%').split(','))
+        # If type is not registered or we don't have a valid object classname,
+        # return the raw value.
         class_info = _SERIALISABLE_TYPES.get(type_name)
         if not class_info:
-            return json_value
+            return json_dict
         # Attempt to import the object's specific class.
         specific_obj_class = _import(specific_obj_classname)
         if specific_obj_class is None:

=== modified file 'src/lazr/json/version.txt'
--- src/lazr/json/version.txt	2012-04-19 07:33:13 +0000
+++ src/lazr/json/version.txt	2012-04-23 00:33:18 +0000
@@ -1,1 +1,1 @@
-0.1
+0.2