Implementing the structured types inspection

wsme/restjson.py

@@ -15,7 +15,7 @@ def prepare_encode(value, datatype):
         return value
     if datatype in wsme.types.structured_types:
         d = dict()
-        for name, datatype, mandatory in wsme.types.list_attributes(value):
+        for name, datatype, mandatory in wsme.types.list_attributes(datatype):
             d[name] = prepare_encode(getattr(value, name), datatype)
         return d
     if datatype in wsme.types.dt_types:

wsme/types.py

@@ -1,5 +1,7 @@
 import datetime
 import decimal
+import weakref
+import inspect
 
 binary = object()
 
@@ -10,6 +12,45 @@ native_types = pod_types + dt_types + extra_types
 
 structured_types = []
 
-def register_type(class_):
-    structured_types.append(class_)
+def mandatory(datatype):
+    if isinstance(datatype, AttrDef):
+        datatype.mandatory = True
+        return datatype
+    return AttrDef(datatype, True)
+
+
+class AttrDef(object):
+    def __init__(self, datatype, mandatory=False, default=None):
+        self.datatype = datatype
+        self.mandatory = mandatory
+        self.default = None
+
+def inspect_class(class_):
+    attributes = []
+    for name in dir(class_):
+        if name.startswith('_'):
+            continue
+            
+        attr = getattr(class_, name)
+        if inspect.isfunction(attr):
+            continue
+        if inspect.ismethod(attr):
+            continue
+        if not isinstance(attr, AttrDef):
+            attrdef = AttrDef(attr)
+        else:
+            attrdef = attr
+
+        attributes.append((name, AttrDef))
+    return attributes
+
+def register_type(class_):
+    if hasattr(class_, '_wsme_attributes'):
+        return
+
+    class_._wsme_attributes = inspect_class(class_)
+    structured_types.append(weakref.ref(class_))
+
+def list_attributes(class_):
+    return class_._wsme_attributes