Add an Eve-aware base class (WIP)

The idea is to provide a base class from which user Tables can inherit.
Unless they are meant for read-only acces, tables will have to provide
these fields anyway.

Not sure on a few things:
- namespace should be different? Maybe have the base-class reside in the
main eve_sqlalchemy namespace, or something different than 'declarative'
to avoid confusion with sqlalchemy itself (I actually followed that
lead).
- base class name. Maybe CommonColumns, or EveBaseModel, or something
else would be more appropriate?
- What if the user changes ETAG, CREATED, UPDATED settings in the main
Eve app?

Again, I am not confident enough with the extension code, so careful
review would be appreciated.

Author: nicolaiarocci

docs/tutorial.rst

@@ -12,7 +12,7 @@ library. This means that you can simply use something like that:
 
 .. literalinclude:: ../eve_sqlalchemy/examples/simple/tables.py
 
-We have used ``CommonColumns`` abstract class to provide attributes used by
+We have used ``BaseModel`` abstract class to provide attributes used by
 Eve, such as ``_created`` and ``_updated``. These are not needed if you are only
 reading from the database. However, if your API is also writing to the database,
 then you need to include them.

docs/upgrading.rst

@@ -29,15 +29,15 @@ directory):
 
 .. code-block:: python
 
-    class People(CommonColumns):
+    class People(BaseModel):
         __tablename__ = 'people'
         id = Column(Integer, primary_key=True, autoincrement=True)
         firstname = Column(String(80))
         lastname = Column(String(120))
         fullname = column_property(firstname + " " + lastname)
 
 
-    class Invoices(CommonColumns):
+    class Invoices(BaseModel):
         __tablename__ = 'invoices'
         id = Column(Integer, primary_key=True, autoincrement=True)
         number = Column(Integer)

eve_sqlalchemy/declarative.py

@@ -0,0 +1,15 @@
+from sqlalchemy import Column, DateTime, String, func
+from sqlalchemy.ext.declarative import declarative_base
+
+
+class BaseModel(object):
+    """
+    Master Eve model for SQLALchemy. It provides common columns such as
+    _created, _updated, and _etag.
+    """
+    _created = Column(DateTime, default=func.now())
+    _updated = Column(DateTime, default=func.now(), onupdate=func.now())
+    _etag = Column(String(40))
+
+
+BaseModel = declarative_base(cls=BaseModel)

eve_sqlalchemy/tests/__init__.py

@@ -19,7 +19,7 @@
 from eve import ISSUES
 
 from eve_sqlalchemy import SQL
-from eve_sqlalchemy.tests.test_sql_tables import Base
+from eve_sqlalchemy.declarative import BaseModel
 from eve_sqlalchemy.validation import ValidatorSQL
 
 
@@ -47,7 +47,7 @@ def setUp(self, settings_file=None, url_converters=None,
         if declarative_base is not None:
             SQL.driver.Model = declarative_base
         else:
-            SQL.driver.Model = Base
+            SQL.driver.Model = BaseModel
 
         self.app = eve.Eve(settings=self.settings_file,
                            url_converters=url_converters, data=SQL,

eve_sqlalchemy/tests/config/__init__.py

@@ -3,6 +3,7 @@
 
 from sqlalchemy import Column, DateTime, String, func
 from sqlalchemy.ext.declarative import declared_attr
+from eve_sqlalchemy.declarative import BaseModel
 
 
 def call_for(*args):
@@ -14,11 +15,8 @@ def loop(self):
     return decorator
 
 
-class BaseModel(object):
+class BaseModel(BaseModel):
     __abstract__ = True
-    _created = Column(DateTime, default=func.now())
-    _updated = Column(DateTime, default=func.now())
-    _etag = Column(String)
 
     @declared_attr
     def __tablename__(cls):

eve_sqlalchemy/tests/integration/collection_class_set.py

@@ -1,27 +1,16 @@
 # -*- coding: utf-8 -*-
 from __future__ import unicode_literals
 
-from sqlalchemy import (
-    Column, DateTime, ForeignKey, Integer, String, Table, func,
-)
-from sqlalchemy.ext.declarative import declarative_base
+from sqlalchemy import Column, ForeignKey, Integer, Table
 from sqlalchemy.orm import relationship
 
 from eve_sqlalchemy.config import DomainConfig, ResourceConfig
+from eve_sqlalchemy.declarative import BaseModel
 from eve_sqlalchemy.tests import TestMinimal
 
-Base = declarative_base()
-
-
-class BaseModel(Base):
-    __abstract__ = True
-    _created = Column(DateTime, default=func.now())
-    _updated = Column(DateTime, default=func.now(), onupdate=func.now())
-    _etag = Column(String(40))
-
 
 association_table = Table(
-    'association', Base.metadata,
+    'association', BaseModel.metadata,
     Column('left_id', Integer, ForeignKey('left.id')),
     Column('right_id', Integer, ForeignKey('right.id'))
 )
@@ -55,7 +44,7 @@ class TestCollectionClassSet(TestMinimal):
 
     def setUp(self, url_converters=None):
         super(TestCollectionClassSet, self).setUp(
-            SETTINGS, url_converters, Base)
+            SETTINGS, url_converters, BaseModel)
 
     def bulk_insert(self):
         self.app.data.insert('children', [{'id': k} for k in range(1, 5)])

eve_sqlalchemy/tests/integration/get_none_values.py

@@ -2,19 +2,11 @@
 from __future__ import unicode_literals
 
 from sqlalchemy import Column, DateTime, Integer, String, func
-from sqlalchemy.ext.declarative import declarative_base
 
 from eve_sqlalchemy.config import DomainConfig, ResourceConfig
 from eve_sqlalchemy.tests import TestMinimal
 
-Base = declarative_base()
-
-
-class BaseModel(Base):
-    __abstract__ = True
-    _created = Column(DateTime, default=func.now())
-    _updated = Column(DateTime, default=func.now(), onupdate=func.now())
-    _etag = Column(String(40))
+from eve_sqlalchemy.declarative import BaseModel
 
 
 class Node(BaseModel):
@@ -37,7 +29,7 @@ class Node(BaseModel):
 class TestGetNoneValues(TestMinimal):
 
     def setUp(self, url_converters=None):
-        super(TestGetNoneValues, self).setUp(SETTINGS, url_converters, Base)
+        super(TestGetNoneValues, self).setUp(SETTINGS, url_converters, BaseModel)
 
     def bulk_insert(self):
         self.app.data.insert('nodes', [{'id': k} for k in range(1, 5)])

eve_sqlalchemy/tests/test_sql_tables.py

@@ -1,54 +1,28 @@
 # -*- coding: utf-8 -*-
 from __future__ import unicode_literals
 
-import hashlib
-
-from sqlalchemy import (
-    Boolean, Column, DateTime, Float, ForeignKey, Integer, LargeBinary,
-    PickleType, String, Table, func,
-)
-from sqlalchemy.ext.declarative import declarative_base
+from sqlalchemy import Boolean, Column, DateTime, Float, ForeignKey, Integer, LargeBinary, PickleType, String, Table
 from sqlalchemy.orm import relationship
 
-Base = declarative_base()
-
-
-class CommonColumns(Base):
-    """
-    Master SQLAlchemy Model. All the SQL tables defined for the application
-    should inherit from this class. It provides common columns such as
-    _created, _updated and _id.
-
-    WARNING: the _id column name does not respect Eve's setting for custom
-    ID_FIELD.
-    """
-    __abstract__ = True
-    _created = Column(DateTime, default=func.now())
-    _updated = Column(DateTime, default=func.now(), onupdate=func.now())
-    _etag = Column(String)
-
-    def __init__(self, *args, **kwargs):
-        h = hashlib.sha1()
-        self._etag = h.hexdigest()
-        super(CommonColumns, self).__init__(*args, **kwargs)
+from eve_sqlalchemy.declarative import BaseModel
 
 
-class DisabledBulk(CommonColumns):
+class DisabledBulk(BaseModel):
     __tablename__ = 'disabled_bulk'
     _id = Column(Integer, primary_key=True)
     string_field = Column(String(25))
 
 
 InvoicingContacts = Table(
-    'invoicing_contacts', Base.metadata,
+    'invoicing_contacts', BaseModel.metadata,
     Column('invoice_id', Integer, ForeignKey('invoices._id'),
            primary_key=True),
     Column('contact_id', Integer, ForeignKey('contacts._id'),
            primary_key=True)
 )
 
 
-class Contacts(CommonColumns):
+class Contacts(BaseModel):
     __tablename__ = 'contacts'
     _id = Column(Integer, primary_key=True)
     ref = Column(String(25), unique=True, nullable=False)
@@ -81,7 +55,7 @@ class Contacts(CommonColumns):
     abool = Column(Boolean)
 
 
-class Invoices(CommonColumns):
+class Invoices(BaseModel):
     __tablename__ = 'invoices'
     _id = Column(Integer, primary_key=True)
     inv_number = Column(String(25))
@@ -90,66 +64,66 @@ class Invoices(CommonColumns):
     invoicing_contacts = relationship('Contacts', secondary=InvoicingContacts)
 
 
-class Empty(CommonColumns):
+class Empty(BaseModel):
     __tablename__ = 'empty'
     _id = Column(Integer, primary_key=True)
     inv_number = Column(String(25))
 
 
 DepartmentsContacts = Table(
-    'department_contacts', Base.metadata,
+    'department_contacts', BaseModel.metadata,
     Column('department_id', Integer, ForeignKey('departments._id'),
            primary_key=True),
     Column('contact_id', Integer, ForeignKey('contacts._id'),
            primary_key=True)
 )
 
 CompaniesDepartments = Table(
-    'companies_departments', Base.metadata,
+    'companies_departments', BaseModel.metadata,
     Column('company_id', Integer, ForeignKey('companies._id'),
            primary_key=True),
     Column('department_id', Integer, ForeignKey('departments._id'),
            primary_key=True)
 )
 
 
-class Departments(CommonColumns):
+class Departments(BaseModel):
     __tablename__ = 'departments'
     _id = Column(Integer, primary_key=True)
     title = Column(String(25))
     members = relationship('Contacts', secondary=DepartmentsContacts)
 
 
-class Companies(CommonColumns):
+class Companies(BaseModel):
     __tablename__ = 'companies'
     _id = Column(Integer, primary_key=True)
     holding_id = Column(String(16), ForeignKey('companies._id'))
     holding = relationship('Companies', remote_side=[_id])
     departments = relationship('Departments', secondary=CompaniesDepartments)
 
 
-class Payments(CommonColumns):
+class Payments(BaseModel):
     __tablename__ = 'payments'
     _id = Column(Integer, primary_key=True)
     a_string = Column(String(10))
     a_number = Column(Integer)
 
 
-class InternalTransactions(CommonColumns):
+class InternalTransactions(BaseModel):
     __tablename__ = 'internal_transactions'
     _id = Column(Integer, primary_key=True)
     internal_string = Column(String(10))
     internal_number = Column(Integer)
 
 
-class Login(CommonColumns):
+class Login(BaseModel):
     __tablename__ = 'login'
     _id = Column(Integer, primary_key=True)
     email = Column(String(255), nullable=False, unique=True)
     password = Column(String(32), nullable=False)
 
 
-class Products(CommonColumns):
+class Products(BaseModel):
     __tablename__ = 'products'
     sku = Column(String(16), primary_key=True)
     title = Column(String(32))