Add a generic serialization interface

Author: ghanse

dbldatagen/serialization.py

@@ -0,0 +1,47 @@
+""" Defines interface contracts."""
+import sys
+
+
+class Serializable:
+    """ Serializable objects must implement a `toDict` method which
+        converts the object properties to a Python dictionary whose
+        keys are the named arguments to the class constructor.
+    """
+
+    @classmethod
+    def getMapping(cls):
+        """ Returns the internal mapping dictionary for the class.
+            You must implement this method to make classes serializable
+            via `fromDict` and `toDict`.
+        """
+        raise NotImplementedError(f"Object is not serializable. {cls.__name__} does not implement '_args'")
+
+    @classmethod
+    def fromDict(cls, options):
+        """ Converts a Python Dictionary to the object using the object's constructor."""
+        internal_representation = options.copy()
+        internal_representation.pop("kind")
+        d = {}
+        for key, value in internal_representation.items():
+            if isinstance(value, dict):
+                c = value.get("kind")
+                if dict in [type(i) for i in value.values()]:
+                    d[key] = getattr(sys.modules[__name__], c).fromDict(value)
+                    continue
+                value.pop("kind")
+                d[key] = getattr(sys.modules[__name__], c)(**value)
+                continue
+            d[key] = value
+        return cls(**d)
+
+    def toDict(self):
+        """ Converts the object to a Python dictionary with the object's constructor arguments."""
+        args = self.getMapping()
+        return {"kind": self.__class__.__name__,
+                **{
+                    public_key: getattr(self, internal_key).toDict()
+                    if isinstance(getattr(self, internal_key), Serializable)
+                    else getattr(self, internal_key)
+                    for public_key, internal_key in args.items()
+                    if hasattr(self, internal_key) and getattr(self, internal_key) is not None
+                }}