General internal enhancements (#5)

- Private API attributes and functions now all start with a single underscore.
- Models have a "_fields" attribute to access the Fields dictionary.
- Model.from_json() method now also accepts a "strict" option.
- Missing keys when deserializing will now raise a DeserializationError
instead of a ValidationError.
- Update tests to assert the above.
- Various docstring updates.

CHANGES.rst

@@ -1,6 +1,15 @@
 Changelog
 =========
 
+Version 0.2.0
+-------------
+
+*Unreleased*
+
+- General internal enhancements (`#5`_)
+
+.. _#5: https://github.com/rossmacarthur/serde/pull/5
+
 Version 0.1.2
 -------------
 

serde/error.py

@@ -17,9 +17,9 @@ def __init__(self, message, cause=None, field=None, model=None):
             field (~serde.field.Field): the field context.
             model (~serde.model.Model): the model context.
         """
-        super().__init__()
-        self.message = message
+        super().__init__(message)
         self.cause = cause
+        self.field = field
         self.model = model
 
     def add_context(self, cause=None, field=None, model=None):
@@ -36,13 +36,13 @@ def __repr__(self):
         """
         return '<{}.{}: {}>'.format(self.__class__.__module__,
                                     self.__class__.__qualname__,
-                                    self.message)
+                                    str(self))
 
     def __str__(self):
         """
         Return a string representation of this SerdeError.
         """
-        return self.message
+        return self.args[0]
 
 
 class SerializationError(SerdeError):

serde/field/core.py

@@ -11,7 +11,7 @@ def resolve_to_field_instance(thing, none_allowed=True):
     Resolve an arbitrary object to a `Field` instance.
 
     Args:
-        thing (object): anything to resolve to a Field instance.
+        thing: anything to resolve to a Field instance.
         none_allowed (bool): if set then a thing of None will be resolved to a
             generic Field.
 
@@ -21,16 +21,16 @@ def resolve_to_field_instance(thing, none_allowed=True):
     # We import Model here to avoid circular dependency problems.
     from serde.model import Model
 
-    # If the things is None
-    if none_allowed is True and thing is None:
+    # If the thing is None then create a generic Field.
+    if none_allowed and thing is None:
         return Field()
 
     # If the thing is a Field then thats great.
-    if isinstance(thing, Field):
+    elif isinstance(thing, Field):
         return thing
 
     # If the thing is a subclass of Field then attempt to create an instance.
-    # This could fail the Field expects arguments.
+    # This could fail the Field expects positional arguments.
     try:
         if issubclass(thing, Field):
             return thing()
@@ -44,7 +44,8 @@ def resolve_to_field_instance(thing, none_allowed=True):
     except TypeError:
         pass
 
-    # If the thing is a built-in type then create a InstanceField with that type.
+    # If the thing is a built-in type that we support then create an
+    # InstanceField with that type.
     field_class = {
         bool: Bool,
         dict: Dict,
@@ -72,7 +73,7 @@ class Field:
     Here is a simple example of how Fields can be used on a Model. In this
     example we use the base class Field which does not have any of its own
     validation, and simply passes values through when serializing and
-    deserializing.
+    deserializing. Typically, more constrained Field classes would be used.
 
     .. doctest::
 
@@ -125,7 +126,7 @@ class Field:
     """
 
     # This is so we can get the order the fields were instantiated in.
-    __counter__ = 0
+    __counter = 0
 
     def __init__(self, rename=None, required=True, default=None, validators=None):
         """
@@ -145,8 +146,8 @@ def __init__(self, rename=None, required=True, default=None, validators=None):
         """
         super().__init__()
 
-        self.id = Field.__counter__
-        Field.__counter__ += 1
+        self.id = Field.__counter
+        Field.__counter += 1
 
         self.rename = rename
         self.required = required
@@ -155,10 +156,10 @@ def __init__(self, rename=None, required=True, default=None, validators=None):
 
     def __attrs__(self):
         """
-        Return all attributes of this Field except "id".
+        Return all attributes of this Field except "id" and "_name".
         """
         return {name: value for name, value in vars(self).items()
-                if name not in ('id', '__name__')}
+                if name not in ('id', '_name')}
 
     def __eq__(self, other):
         """
@@ -179,15 +180,15 @@ def __setattr__(self, name, value):
         Set a named attribute on a Field.
 
         Raises:
-            `~serde.error.SerdeError`: when the __name__ attribute is set after
-                it has already been set.
+            `~serde.error.SerdeError`: when the _name attribute is set after it
+                has already been set.
         """
-        if name == '__name__' and hasattr(self, '__name__'):
+        if name == '_name' and hasattr(self, '_name'):
             raise SerdeError('field instance used multiple times')
 
         super().__setattr__(name, value)
 
-    def __validate__(self, value):
+    def _validate(self, value):
         """
         Validate the given value according to this Field's specification.
 
@@ -197,7 +198,7 @@ def __validate__(self, value):
             value: the value to validate.
         """
         if value is None:
-            if self.required is True:
+            if self.required:
                 raise ValidationError('{!r} is required'.format(self.name))
 
             return
@@ -215,11 +216,11 @@ def name(self):
         This is the rename value, given when the Field is instantiated,
         otherwise the attribute name of this Field on the Model.
         """
-        if not hasattr(self, '__name__'):
+        if not hasattr(self, '_name'):
             raise SerdeError('field is not on a Model')
 
         if self.rename is None:
-            return self.__name__
+            return self._name
 
         return self.rename
 
@@ -786,7 +787,7 @@ def deserialize(self, value):
         """
         value = super().deserialize(value)
 
-        if self.strip is True:
+        if self.strip:
             value = value.strip()
 
         return value