Merge pull request #101 from CaselIT/sortable_field

Added sort support

Author: syrusakbary

docs/examples.rst

@@ -3,22 +3,32 @@ Schema Examples
 
 
 Search all Models with Union
------------------
+----------------------------
 
 .. code:: python
 
     class Book(SQLAlchemyObjectType):
         class Meta:
             model = BookModel
             interfaces = (relay.Node,)
-    
-    
+
+
+    class BookConnection(relay.Connection):
+        class Meta:
+            node = Book
+
+
     class Author(SQLAlchemyObjectType):
         class Meta:
             model = AuthorModel
             interfaces = (relay.Node,)
 
 
+    class AuthorConnection(relay.Connection):
+        class Meta:
+            node = Author
+
+
     class SearchResult(graphene.Union):
         class Meta:
             types = (Book, Author)
@@ -29,8 +39,8 @@ Search all Models with Union
         search = graphene.List(SearchResult, q=graphene.String())  # List field for search results
         
         # Normal Fields
-        all_books = SQLAlchemyConnectionField(Book)
-        all_authors = SQLAlchemyConnectionField(Author)
+        all_books = SQLAlchemyConnectionField(BookConnection)
+        all_authors = SQLAlchemyConnectionField(AuthorConnection)
 
         def resolve_search(self, info, **args):
             q = args.get("q")  # Search query
@@ -47,13 +57,13 @@ Search all Models with Union
             # Query Authors
             authors = author_query.filter(AuthorModel.name.contains(q)).all()
 
-        return authors + books  # Combine lists
+            return authors + books  # Combine lists
 
     schema = graphene.Schema(query=Query, types=[Book, Author, SearchResult])
     
 Example GraphQL query
 
-.. code:: GraphQL
+.. code::
 
     book(id: "Qm9vazow") {
         id

docs/tips.rst

@@ -2,9 +2,6 @@
 Tips
 ====
 
-Tips
-====
-
 Querying
 --------
 
@@ -30,3 +27,61 @@ For make querying to the database work, there are two alternatives:
 If you don't specify any, the following error will be displayed:
 
 ``A query in the model Base or a session in the schema is required for querying.``
+
+Sorting
+-------
+
+By default the SQLAlchemyConnectionField sorts the result elements over the primary key(s). 
+The query has a `sort` argument which allows to sort over a different column(s)
+
+Given the model
+
+.. code:: python
+
+    class Pet(Base):
+        __tablename__ = 'pets'
+        id = Column(Integer(), primary_key=True)
+        name = Column(String(30))
+        pet_kind = Column(Enum('cat', 'dog', name='pet_kind'), nullable=False)
+
+
+    class PetNode(SQLAlchemyObjectType):
+        class Meta:
+            model = Pet
+
+
+    class PetConnection(Connection):
+        class Meta:
+            node = PetNone
+
+
+    class Query(ObjectType):
+        allPets = SQLAlchemyConnectionField(PetConnection)
+
+some of the allowed queries are
+
+-  Sort in ascending order over the `name` column
+
+.. code::
+
+    allPets(sort: name_asc){
+        edges {
+            node {
+                name
+            }
+        }
+    }
+
+-  Sort in descending order over the `per_kind` column and in ascending order over the `name` column
+
+.. code::
+
+    allPets(sort: [pet_kind_desc, name_asc]) {
+        edges {
+            node {
+                name
+                petKind
+            }
+        }
+    }
+

docs/tutorial.rst

@@ -102,15 +102,28 @@ Create ``flask_sqlalchemy/schema.py`` and type the following:
             interfaces = (relay.Node, )
 
 
+    class DepartmentConnection(relay.Connection):
+        class Meta:
+            node = Department
+
+
     class Employee(SQLAlchemyObjectType):
         class Meta:
             model = EmployeeModel
             interfaces = (relay.Node, )
 
 
+    class EmployeeConnection(relay.Connection):
+        class Meta:
+            node = Employee
+
+
     class Query(graphene.ObjectType):
         node = relay.Node.Field()
-        all_employees = SQLAlchemyConnectionField(Employee)
+        # Allows sorting over multiple columns, by default over the primary key
+        all_employees = SQLAlchemyConnectionField(EmployeeConnection)
+        # Disable sorting over this field
+        all_departments = SQLAlchemyConnectionField(DepartmentConnection, sort=None)
 
     schema = graphene.Schema(query=Query)
 

examples/flask_sqlalchemy/schema.py

@@ -1,37 +1,60 @@
 import graphene
 from graphene import relay
-from graphene_sqlalchemy import SQLAlchemyConnectionField, SQLAlchemyObjectType
+from graphene_sqlalchemy import SQLAlchemyConnectionField, SQLAlchemyObjectType, utils
 from models import Department as DepartmentModel
 from models import Employee as EmployeeModel
 from models import Role as RoleModel
 
 
 class Department(SQLAlchemyObjectType):
-
     class Meta:
         model = DepartmentModel
         interfaces = (relay.Node, )
 
 
-class Employee(SQLAlchemyObjectType):
+class DepartmentConnection(relay.Connection):
+    class Meta:
+        node = Department
+
 
+class Employee(SQLAlchemyObjectType):
     class Meta:
         model = EmployeeModel
         interfaces = (relay.Node, )
 
 
-class Role(SQLAlchemyObjectType):
+class EmployeeConnection(relay.Connection):
+    class Meta:
+        node = Employee
 
+
+class Role(SQLAlchemyObjectType):
     class Meta:
         model = RoleModel
         interfaces = (relay.Node, )
 
 
+class RoleConnection(relay.Connection):
+    class Meta:
+        node = Role
+
+
+SortEnumEmployee = utils.sort_enum_for_model(EmployeeModel, 'SortEnumEmployee',
+    lambda c, d: c.upper() + ('_ASC' if d else '_DESC'))
+
+
 class Query(graphene.ObjectType):
     node = relay.Node.Field()
-    all_employees = SQLAlchemyConnectionField(Employee)
-    all_roles = SQLAlchemyConnectionField(Role)
-    role = graphene.Field(Role)
+    # Allow only single column sorting
+    all_employees = SQLAlchemyConnectionField(
+        EmployeeConnection,
+        sort=graphene.Argument(
+            SortEnumEmployee,
+            default_value=utils.EnumValue('id_asc', EmployeeModel.id.asc())))
+    # Allows sorting over multiple columns, by default over the primary key
+    all_roles = SQLAlchemyConnectionField(RoleConnection)
+    # Disable sorting over this field
+    all_departments = SQLAlchemyConnectionField(DepartmentConnection, sort=None)
 
 
 schema = graphene.Schema(query=Query, types=[Department, Employee, Role])

graphene_sqlalchemy/fields.py

@@ -2,22 +2,28 @@
 from promise import is_thenable, Promise
 from sqlalchemy.orm.query import Query
 
-from graphene.relay import ConnectionField
+from graphene.relay import Connection, ConnectionField
 from graphene.relay.connection import PageInfo
 from graphql_relay.connection.arrayconnection import connection_from_list_slice
 
-from .utils import get_query
+from .utils import get_query, sort_argument_for_model
 
 
-class SQLAlchemyConnectionField(ConnectionField):
+class UnsortedSQLAlchemyConnectionField(ConnectionField):
 
     @property
     def model(self):
         return self.type._meta.node._meta.model
 
     @classmethod
-    def get_query(cls, model, info, **args):
-        return get_query(model, info.context)
+    def get_query(cls, model, info, sort=None, **args):
+        query = get_query(model, info.context)
+        if sort is not None:
+            if isinstance(sort, str):
+                query = query.order_by(sort.value)
+            else:
+                query = query.order_by(*(col.value for col in sort))
+        return query
 
     @classmethod
     def resolve_connection(cls, connection_type, model, info, args, resolved):
@@ -55,7 +61,25 @@ def get_resolver(self, parent_resolver):
         return partial(self.connection_resolver, parent_resolver, self.type, self.model)
 
 
-__connectionFactory = SQLAlchemyConnectionField
+class SQLAlchemyConnectionField(UnsortedSQLAlchemyConnectionField):
+
+    def __init__(self, type, *args, **kwargs):
+        if 'sort' not in kwargs and issubclass(type, Connection):
+            # Let super class raise if type is not a Connection
+            try:
+                model = type.Edge.node._type._meta.model
+                kwargs.setdefault('sort', sort_argument_for_model(model))
+            except Exception:
+                raise Exception(
+                    'Cannot create sort argument for {}. A model is required. Set the "sort" argument'
+                    ' to None to disabling the creation of the sort query argument'.format(type.__name__)
+                )
+        elif 'sort' in kwargs and kwargs['sort'] is None:
+            del kwargs['sort']
+        super(SQLAlchemyConnectionField, self).__init__(type, *args, **kwargs)
+
+
+__connectionFactory = UnsortedSQLAlchemyConnectionField
 
 
 def createConnectionField(_type):
@@ -69,4 +93,4 @@ def registerConnectionFieldFactory(factoryMethod):
 
 def unregisterConnectionFieldFactory():
     global __connectionFactory
-    __connectionFactory = SQLAlchemyConnectionField
+    __connectionFactory = UnsortedSQLAlchemyConnectionField

graphene_sqlalchemy/tests/test_converter.py

@@ -16,7 +16,7 @@
 from ..converter import (convert_sqlalchemy_column,
                          convert_sqlalchemy_composite,
                          convert_sqlalchemy_relationship)
-from ..fields import SQLAlchemyConnectionField
+from ..fields import UnsortedSQLAlchemyConnectionField
 from ..registry import Registry
 from ..types import SQLAlchemyObjectType
 from .models import Article, Pet, Reporter
@@ -205,7 +205,7 @@ class Meta:
 
     dynamic_field = convert_sqlalchemy_relationship(Reporter.pets.property, A._meta.registry)
     assert isinstance(dynamic_field, graphene.Dynamic)
-    assert isinstance(dynamic_field.get_type(), SQLAlchemyConnectionField)
+    assert isinstance(dynamic_field.get_type(), UnsortedSQLAlchemyConnectionField)
 
 
 def test_should_manytoone_convert_connectionorlist():

graphene_sqlalchemy/tests/test_fields.py

@@ -0,0 +1,38 @@
+from graphene.relay import Connection
+import pytest
+
+from ..fields import SQLAlchemyConnectionField
+from ..types import SQLAlchemyObjectType
+from ..utils import sort_argument_for_model
+from .models import Pet as PetModel, Editor
+
+
+class Pet(SQLAlchemyObjectType):
+    class Meta:
+        model = PetModel
+
+
+class PetConn(Connection):
+    class Meta:
+        node = Pet
+
+
+def test_sort_added_by_default():
+    arg = SQLAlchemyConnectionField(PetConn)
+    assert 'sort' in arg.args
+    assert arg.args['sort'] == sort_argument_for_model(PetModel)
+
+
+def test_sort_can_be_removed():
+    arg = SQLAlchemyConnectionField(PetConn, sort=None)
+    assert 'sort' not in arg.args
+
+
+def test_custom_sort():
+    arg = SQLAlchemyConnectionField(PetConn, sort=sort_argument_for_model(Editor))
+    assert arg.args['sort'] == sort_argument_for_model(Editor)
+
+
+def test_init_raises():
+    with pytest.raises(Exception, match='Cannot create sort'):
+        SQLAlchemyConnectionField(Connection)