add support for sqlalchemy composite columns

graphene/contrib/sqlalchemy/converter.py

@@ -31,6 +31,30 @@ def convert_sqlalchemy_column(column):
     return convert_sqlalchemy_type(getattr(column, 'type', None), column)
 
 
+def convert_sqlalchemy_composite(composite):
+    try:
+        return convert_sqlalchemy_composite.registry[composite.composite_class](composite)
+    except KeyError:
+        try:
+            raise Exception(
+                "Don't know how to convert the composite field %s (%s)" %
+                (composite, composite.composite_class))
+        except AttributeError:
+            # handle fields that are not attached to a class yet (don't have a parent)
+            raise Exception(
+                "Don't know how to convert the composite field %r (%s)" %
+                (composite, composite.composite_class))
+
+
+def _register_composite_class(cls):
+    def inner(fn):
+        convert_sqlalchemy_composite.registry[cls] = fn
+    return inner
+
+convert_sqlalchemy_composite.registry = {}
+convert_sqlalchemy_composite.register = _register_composite_class
+
+
 @singledispatch
 def convert_sqlalchemy_type(type, column):
     raise Exception(

graphene/contrib/sqlalchemy/tests/test_converter.py

@@ -1,5 +1,6 @@
 from py.test import raises
 from sqlalchemy import Column, Table, types
+from sqlalchemy.orm import composite
 from sqlalchemy.ext.declarative import declarative_base
 from sqlalchemy_utils.types.choice import ChoiceType
 from sqlalchemy.dialects import postgresql
@@ -7,6 +8,7 @@ from sqlalchemy.dialects import postgresql
 import graphene
 from graphene.core.types.custom_scalars import JSONString
 from graphene.contrib.sqlalchemy.converter import (convert_sqlalchemy_column,
+                                                   convert_sqlalchemy_composite,
                                                    convert_sqlalchemy_relationship)
 from graphene.contrib.sqlalchemy.fields import (ConnectionOrListField,
                                                 SQLAlchemyModelField)
@@ -23,6 +25,19 @@ def assert_column_conversion(sqlalchemy_type, graphene_field, **kwargs):
     return field
 
 
+def assert_composite_conversion(composite_class, composite_columns, graphene_field,
+                                **kwargs):
+    composite_column = composite(composite_class, *composite_columns,
+                                 doc='Custom Help Text', **kwargs)
+    graphene_type = convert_sqlalchemy_composite(composite_column)
+    assert isinstance(graphene_type, graphene_field)
+    field = graphene_type.as_field()
+    # SQLAlchemy currently does not persist the doc onto the column, even though
+    # the documentation says it does....
+    # assert field.description == 'Custom Help Text'
+    return field
+
+
 def test_should_unknown_sqlalchemy_field_raise_exception():
     with raises(Exception) as excinfo:
         convert_sqlalchemy_column(None)
@@ -148,3 +163,36 @@ def test_should_postgresql_jsonb_convert():
 
 def test_should_postgresql_hstore_convert():
     assert_column_conversion(postgresql.HSTORE(), JSONString)
+
+
+def test_should_composite_convert():
+
+    class CompositeClass(object):
+        def __init__(self, col1, col2):
+            self.col1 = col1
+            self.col2 = col2
+
+    @convert_sqlalchemy_composite.register(CompositeClass)
+    def convert_composite_class(composite):
+        return graphene.String(description=composite.doc)
+
+    assert_composite_conversion(CompositeClass,
+                                (Column(types.Unicode(50)),
+                                 Column(types.Unicode(50))),
+                                graphene.String)
+
+
+def test_should_unknown_sqlalchemy_composite_raise_exception():
+    with raises(Exception) as excinfo:
+
+        class CompositeClass(object):
+            def __init__(self, col1, col2):
+                self.col1 = col1
+                self.col2 = col2
+
+        assert_composite_conversion(CompositeClass,
+                                    (Column(types.Unicode(50)),
+                                     Column(types.Unicode(50))),
+                                    graphene.String)
+
+    assert 'Don\'t know how to convert the composite field' in str(excinfo.value)

graphene/contrib/sqlalchemy/types.py

@@ -5,9 +5,10 @@ from sqlalchemy.inspection import inspect as sqlalchemyinspect
 from sqlalchemy.orm.exc import NoResultFound
 
 from ...core.classtypes.objecttype import ObjectType, ObjectTypeMeta
-from ...relay.types import Node, NodeMeta
 from ...relay.connection import Connection
+from ...relay.types import Node, NodeMeta
 from .converter import (convert_sqlalchemy_column,
+                        convert_sqlalchemy_composite,
                         convert_sqlalchemy_relationship)
 from .options import SQLAlchemyOptions
 from .utils import get_query, is_mapped
@@ -34,17 +35,25 @@ class SQLAlchemyObjectTypeMeta(ObjectTypeMeta):
             converted_relationship = convert_sqlalchemy_relationship(relationship)
             cls.add_to_class(relationship.key, converted_relationship)
 
-        for name, column in inspected_model.columns.items():
-            is_not_in_only = only_fields and name not in only_fields
-            is_already_created = name in already_created_fields
-            is_excluded = name in exclude_fields or is_already_created
-            if is_not_in_only or is_excluded:
+        def filter_included(l):
+            for name, value in l.items():
+                is_not_in_only = only_fields and name not in only_fields
+                is_already_created = name in already_created_fields
+                is_excluded = name in exclude_fields or is_already_created
                 # We skip this field if we specify only_fields and is not
                 # in there. Or when we excldue this field in exclude_fields
-                continue
+                if is_not_in_only or is_excluded:
+                    continue
+                yield name, value
+
+        for name, column in filter_included(inspected_model.columns):
             converted_column = convert_sqlalchemy_column(column)
             cls.add_to_class(name, converted_column)
 
+        for name, composite in filter_included(inspected_model.composites):
+            converted_composite = convert_sqlalchemy_composite(composite)
+            cls.add_to_class(name, converted_composite)
+
     def construct(cls, *args, **kwargs):
         cls = super(SQLAlchemyObjectTypeMeta, cls).construct(*args, **kwargs)
         if not cls._meta.abstract: