Add support for IFromBytes. Fixes #92

CHANGES.rst

@@ -6,7 +6,9 @@
 1.0.0a13 (unreleased)
 =====================
 
-- Nothing changed yet.
+- Support ``IFromBytes`` fields introduced by zope.schema 4.8.0. See
+  `issue 92
+  <https://github.com/NextThought/nti.externalization/issues/92>`_.
 
 
 1.0.0a12 (2018-09-11)

setup.py

@@ -183,7 +183,7 @@ def _c(m):
         'zope.location',
         'zope.mimetype >= 2.3.0',
         'zope.proxy',
-        'zope.schema >= 4.7.0',
+        'zope.schema >= 4.8.0',
         'zope.security',
     ],
     extras_require={

src/nti/externalization/internalization/_fields.pxd

@@ -26,6 +26,7 @@ cdef notify
 
 # optimizations
 cdef IField_providedBy
+cdef IFromBytes_providedBy
 cdef IFromUnicode_providedBy
 cdef get_exc_info
 

src/nti/externalization/internalization/fields.py

@@ -21,6 +21,7 @@
 from zope.interface import implementedBy
 
 from zope.schema.interfaces import IField
+from zope.schema.interfaces import IFromBytes
 from zope.schema.interfaces import IFromUnicode
 from zope.schema.interfaces import SchemaNotProvided
 from zope.schema.interfaces import SchemaNotCorrectlyImplemented
@@ -35,6 +36,7 @@
 from zope.event import notify
 
 IField_providedBy = IField.providedBy
+IFromBytes_providedBy = IFromBytes.providedBy
 IFromUnicode_providedBy = IFromUnicode.providedBy
 
 __all__ = [
@@ -284,6 +286,8 @@ def validate_field_value(self, field_name, field, value):
     try:
         if isinstance(value, text_type) and IFromUnicode_providedBy(field):
             value = field.fromUnicode(value)  # implies validation
+        elif isinstance(value, bytes) and IFromBytes_providedBy(field):
+            value = field.fromBytes(value)  # implies validation
         else:
             field.validate(value)
     except SchemaNotProvided:

src/nti/externalization/internalization/tests/test_fields.py

@@ -126,6 +126,27 @@ class Foo(object):
         self._callFUT(foo, IFoo, u'field', u'text')()
         assert_that(foo, has_attr('field', u'text'))
 
+    def test_from_bytes(self):
+        from zope.schema.interfaces import IFromBytes
+        from zope.schema import Field
+        @interface.implementer(IFromBytes)
+        class OnlyBytes(Field):
+            _type = bytes
+
+            def fromBytes(self, value):
+                return b'from bytes'
+
+        class IFoo(interface.Interface):
+            field = OnlyBytes(title=u'text')
+
+        class Foo(object):
+            pass
+
+        foo = Foo()
+        self._callFUT(foo, IFoo, u'field', b'text')()
+        assert_that(foo, has_attr('field', b'from bytes'))
+
+
     def test_raises_SchemaNotCorrectlyImplemented(self):
         from zope.schema.interfaces import SchemaNotCorrectlyImplemented
         from zope.schema import TextLine

src/nti/externalization/tests/test_datastructures.py

@@ -413,11 +413,15 @@ class O(object):
         inst.updateFromExternalObject({'ivar': u'2.0'})
         assert_that(ext_self, has_property('ivar', 2.0))
 
-        # A byte string is NOT fine
+        # A byte string is fine
+        inst.updateFromExternalObject({'ivar': b'3.0'})
+
+        # An object is NOT fine
         with self.assertRaises(WrongType):
-            inst.updateFromExternalObject({'ivar': b'3.0'})
+            inst.updateFromExternalObject({'ivar': object()})
 
-        assert_that(ext_self, has_property('ivar', 2.0))
+
+        assert_that(ext_self, has_property('ivar', 3.0))
 
 
         # Now a validation error after set