Merge pull request #11 from knucklesuganda/feature/filter_specifications

Version 1.0.0 of PyAssimilator

Author: knucklesuganda

README.md

@@ -1,9 +1,72 @@
 # Assimilator - the best Python patterns for the best projects
 
-![](/images/logo.png)
+<p align="center">
+  <a href="https://knucklesuganda.github.io/py_assimilator/"><img src="https://knucklesuganda.github.io/py_assimilator/images/logo.png" alt="PyAssimilator"></a>
+</p>
+<p align="center">
+<a href="https://pypi.org/project/py-assimilator/" target="_blank">
+    <img src="https://img.shields.io/github/license/knucklesuganda/py_assimilator?color=%237e56c2&style=for-the-badge" alt="License">
+</a>
+
+<a href="https://pypi.org/project/py-assimilator/" target="_blank">
+    <img src="https://img.shields.io/github/stars/knucklesuganda/py_assimilator?color=%237e56c2&style=for-the-badge" alt="Stars">
+</a>
+<a href="https://pypi.org/project/py-assimilator/" target="_blank">
+    <img src="https://img.shields.io/github/last-commit/knucklesuganda/py_assimilator?color=%237e56c2&style=for-the-badge" alt="Last commit">
+</a>
+</p>
+
 
 ## Install now
-* `pip install py_assimilator`
+* `pip install py-assimilator`
+* `pip install py-assimilator[alchemy]` - Optional SQLAlchemy support 
+* `pip install py-assimilator[kafka]` - Optional Kafka support 
+* `pip install py-assimilator[redis]` - Optional Redis support 
+* `pip install py-assimilator[mongo]` - Optional MongoDB support 
+
+
+## Simple example
+
+Example usage of the code to create a user using all the DDD patterns:
+```Python
+from assimilator.alchemy.database import AlchemyUnitOfWork, AlchemyRepository
+from assimilator.core.database import UnitOfWork
+
+def create_user(username: str, email: str, uow: UnitOfWork):
+    with uow:
+        repository = uow.repository     # Get Repository pattern
+        new_user = repository.save(username=username, email=email, balance=0)
+        uow.commit()    # Securely save the data
+
+    return new_user
+
+
+user_repository = AlchemyRepository(
+    session=alchemy_session,    # alchemy db session
+    model=User,     # alchemy user model 
+)
+user_uow = AlchemyUnitOfWork(repository=user_repository)
+
+create_user(
+    username="Andrey", 
+    email="[email protected]",
+    uow=user_uow,
+)
+
+```
+
+## Why do I need it?
+![](images/why_assimilator_no_usage.png)
+
+Patterns are very useful for good code, but only to some extent. Most of them are not suitable for 
+real life applications. DDD(Domain-driven design) is one of the most popular ways of development
+today, but nobody explains how to write most of DDD patterns in Python. Even if they do, life gives you another
+issue that cannot be solved with a simple algorithm. That is why [Andrey](https://www.youtube.com/channel/UCSNpJHMOU7FqjD4Ttux0uuw) created
+a library for the patterns that he uses in his projects daily.
+
+![](images/why_assimilator_usage.png)
+
+Watch our [Demo]() to find out more about pyAssimilator capabilities.
 
 ## Source
 * [Github](https://github.com/knucklesuganda/py_assimilator)
@@ -13,24 +76,23 @@
 * [Author's YouTube RU](https://www.youtube.com/channel/UCSNpJHMOU7FqjD4Ttux0uuw)
 * [Author's YouTube ENG](https://www.youtube.com/channel/UCeC9LNDwRP9OfjyOFHaSikA)
 
-## About patterns in coding
-They are useful, but only to some extent. Most of them are not suitable for 
-real life applications. DDD(Domain-driven design) is one of the most popular ways of development
-today, but nobody explains how to write most of DDD patterns in Python. Even if they do, life gives you another
-issue that cannot be solved with a simple algorithm. That is why [Andrey](https://www.youtube.com/channel/UCSNpJHMOU7FqjD4Ttux0uuw) created
-a library for the patterns that he uses in his projects daily.
+
+## Stars history
+[![Star History Chart](https://api.star-history.com/svg?repos=knucklesuganda/py_assimilator&type=Date)](https://star-history.com/#knucklesuganda/py_assimilator&Date)
+
 
 ## Types of patterns
-These are different use cases for the patterns implemented.
+These are different use cases for the patterns implemented:
 
-- Database - patterns for database/data layer interactions
-- Events - projects with events or event-driven architecture
+- Database - patterns for database/data layer interactions.
+- Events(in development) - projects with events or event-driven architecture.
+- Unidentified - patterns that are useful for different purposes.
 
 ## Available providers
-Providers are different patterns for external modules like SQLAlchemy or 
-FastAPI.
+Providers are different patterns for external modules like SQLAlchemy or FastAPI.
 
-- Alchemy(Database, Events) - patterns for [SQLAlchemy](https://docs.sqlalchemy.org/en/20/) for both database and events
-- Kafka(Events) - patterns in [Kafka](https://kafka.apache.org/) related to events
-- Internal(Database, Events) - internal is the type of provider that saves everything in memory(dict, list and all the tools within your app)
-- Redis(Database, Events) - redis allows us to work with [Redis](https://redis.io/) memory database
+- Alchemy(Database, Events) - patterns for [SQLAlchemy](https://docs.sqlalchemy.org/en/20/) for both database and events.
+- Kafka(Events) - patterns in [Kafka](https://kafka.apache.org/) related to events.
+- Internal(Database, Events) - internal is the type of provider that saves everything in memory(dict, list and all the tools within your app).
+- Redis(Database, Events) - redis_ allows us to work with [Redis](https://redis.io/) memory database.
+- MongoDB(Database) - mongo allows us to work with [MongoDB](https://www.mongodb.com/) database.

assimilator/__init__.py

@@ -1,27 +1 @@
-from contextlib import contextmanager
-
-import assimilator.core
-import assimilator.internal
-
-
-@contextmanager
-def optional_dependencies(error: str = "ignore"):
-    assert error in {"raise", "warn", "ignore"}
-    try:
-        yield None
-    except ImportError as e:
-        if error == "raise":
-            raise e
-        if error == "warn":
-            msg = f'Missing optional dependency "{e.name}". Use pip or conda to install.'
-            print(f'Warning: {msg}')
-
-
-with optional_dependencies():
-    import assimilator.alchemy
-
-with optional_dependencies():
-    import assimilator.kafka_
-
-with optional_dependencies():
-    import assimilator.redis_ as redis
+# TODO: change demo link in docs

assimilator/alchemy/__init__.py

@@ -1,2 +0,0 @@
-from assimilator.alchemy.events import *
-from assimilator.alchemy.database import *

assimilator/alchemy/database/__init__.py

@@ -1,3 +1,4 @@
 from assimilator.alchemy.database.repository import *
-from assimilator.alchemy.database.specifications import *
+from assimilator.alchemy.database.specifications.specifications import *
+from assimilator.alchemy.database.specifications.filtering_options import *
 from assimilator.alchemy.database.unit_of_work import *

assimilator/alchemy/database/error_wrapper.py

@@ -1,6 +1,11 @@
-from sqlalchemy.exc import NoResultFound, IntegrityError, SQLAlchemyError
+from sqlalchemy.exc import NoResultFound, IntegrityError, SQLAlchemyError, MultipleResultsFound
 
-from assimilator.core.database.exceptions import DataLayerError, NotFoundError, InvalidQueryError
+from assimilator.core.database.exceptions import (
+    DataLayerError,
+    NotFoundError,
+    InvalidQueryError,
+    MultipleResultsError,
+)
 from assimilator.core.patterns.error_wrapper import ErrorWrapper
 
 
@@ -10,6 +15,7 @@ def __init__(self):
             NoResultFound: NotFoundError,
             IntegrityError: InvalidQueryError,
             SQLAlchemyError: DataLayerError,
+            MultipleResultsFound: MultipleResultsError,
         }, default_error=DataLayerError)
 
 

assimilator/alchemy/database/model_utils.py

@@ -0,0 +1,40 @@
+from typing import TypeVar, Type
+
+from sqlalchemy import inspect
+
+
+T = TypeVar("T")
+
+
+def get_model_from_relationship(model: T, relationship_name: str):
+    foreign_prop = getattr(model, relationship_name).property
+    return foreign_prop.mapper.class_, foreign_prop.uselist
+
+
+def dict_to_models(data: dict, model: Type[T]) -> T:
+    for relationship in inspect(model).relationships.keys():
+        foreign_data = data.get(relationship)
+        if foreign_data is None:
+            continue
+
+        foreign_model, is_list = get_model_from_relationship(
+            model=model,
+            relationship_name=relationship,
+        )
+
+        if not is_list and isinstance(foreign_data, dict):
+            foreign_data = dict_to_models(data=foreign_data, model=foreign_model)
+            foreign_data = foreign_model(**foreign_data)
+        elif is_list:
+            foreign_models = (
+                foreign_data for foreign_data in foreign_data
+                if isinstance(foreign_data, dict)
+            )
+
+            for i, foreign_part in enumerate(foreign_models):
+                foreign_part = dict_to_models(data=foreign_part, model=foreign_model)
+                foreign_data[i] = foreign_model(**foreign_part)
+
+        data[relationship] = foreign_data
+
+    return data

assimilator/alchemy/database/repository.py

@@ -1,15 +1,15 @@
 from typing import Type, Union, Optional, TypeVar, Collection
 
-from sqlalchemy import func, select, update, delete
-from sqlalchemy.orm import Session, Query
+from sqlalchemy import func, select, update, delete, Delete
+from sqlalchemy.orm import Session, Query   # TODO: change query for alchemy 2
 from sqlalchemy.inspection import inspect
 
-from assimilator.alchemy.database.error_wrapper import AlchemyErrorWrapper
+from assimilator.alchemy.database.model_utils import dict_to_models
+from assimilator.core.patterns.error_wrapper import ErrorWrapper
 from assimilator.core.database.exceptions import InvalidQueryError
+from assimilator.alchemy.database.error_wrapper import AlchemyErrorWrapper
 from assimilator.alchemy.database.specifications import AlchemySpecificationList
-from assimilator.core.database import Repository, SpecificationList, \
-    LazyCommand, SpecificationType, make_lazy
-from assimilator.core.patterns.error_wrapper import ErrorWrapper
+from assimilator.core.database import Repository, LazyCommand, SpecificationType
 
 
 AlchemyModelT = TypeVar("AlchemyModelT")
@@ -24,7 +24,7 @@ def __init__(
         session: Session,
         model: Type[AlchemyModelT],
         initial_query: Query = None,
-        specifications: Type[SpecificationList] = AlchemySpecificationList,
+        specifications: Type[AlchemySpecificationList] = AlchemySpecificationList,
         error_wrapper: Optional[ErrorWrapper] = None,
     ):
         super(AlchemyRepository, self).__init__(
@@ -35,33 +35,36 @@ def __init__(
             error_wrapper=error_wrapper or AlchemyErrorWrapper(),
         )
 
-    @make_lazy
     def get(
         self,
         *specifications: SpecificationType,
         lazy: bool = False,
         initial_query: Query = None,
     ) -> Union[AlchemyModelT, LazyCommand[AlchemyModelT]]:
         query = self._apply_specifications(
-            query=self.get_initial_query(initial_query),
+            query=initial_query,
             specifications=specifications,
         )
         return self.session.execute(query).one()[0]
 
-    @make_lazy
     def filter(
         self,
         *specifications: SpecificationType,
         lazy: bool = False,
         initial_query: Query = None,
     ) -> Union[Collection[AlchemyModelT], LazyCommand[Collection[AlchemyModelT]]]:
         query = self._apply_specifications(
-            query=self.get_initial_query(initial_query),
+            query=initial_query,
             specifications=specifications,
         )
         return [result[0] for result in self.session.execute(query)]
 
-    def update(self, obj: Optional[AlchemyModelT] = None, *specifications, **update_values) -> None:
+    def update(
+        self,
+        obj: Optional[AlchemyModelT] = None,
+        *specifications: SpecificationType,
+        **update_values,
+    ) -> None:
         obj, specifications = self._check_obj_is_specification(obj, specifications)
 
         if specifications:
@@ -71,58 +74,66 @@ def update(self, obj: Optional[AlchemyModelT] = None, *specifications, **update_
                     "to the update() yet provided specifications"
                 )
 
-            query: Query = self._apply_specifications(
-                query=self.get_initial_query(update(self.model)),
+            query = self._apply_specifications(
+                query=update(self.model),
                 specifications=specifications,
             )
-            self.session.execute(query.values(update_values))
+
+            self.session.execute(
+                query.values(update_values).execution_options(synchronize_session=False)
+            )
+
         elif obj is not None:
+            if obj not in self.session:
+                obj = self.session.merge(obj)
+
             self.session.add(obj)
 
     def save(self, obj: Optional[AlchemyModelT] = None, **data) -> AlchemyModelT:
         if obj is None:
-            obj = self.model(**data)
+            obj = self.model(**dict_to_models(data=data, model=self.model))
 
         self.session.add(obj)
         return obj
 
     def refresh(self, obj: AlchemyModelT) -> None:
-        inspection = inspect(obj)
-
-        if inspection.transient or inspection.pending:
-            return
-        elif inspection.detached:
-            self.session.add(obj)
+        if obj not in self.session:
+            obj = self.session.merge(obj)
 
         self.session.refresh(obj)
 
     def delete(self, obj: Optional[AlchemyModelT] = None, *specifications: SpecificationType) -> None:
         obj, specifications = self._check_obj_is_specification(obj, specifications)
 
         if specifications:
-            query: Query = self._apply_specifications(
-                query=self.get_initial_query(delete(self.model)),
+            query: Delete = self._apply_specifications(
+                query=delete(self.model),
                 specifications=specifications,
             )
-            self.session.execute(query)
+            self.session.execute(query.execution_options(synchronize_session=False))
         elif obj is not None:
             self.session.delete(obj)
 
     def is_modified(self, obj: AlchemyModelT) -> bool:
-        return self.session.is_modified(obj)
+        return obj in self.session and self.session.is_modified(obj)
 
-    @make_lazy
-    def count(self, *specifications: SpecificationType, lazy: bool = False) -> Union[LazyCommand[int], int]:
+    def count(
+        self,
+        *specifications: SpecificationType,
+        lazy: bool = False,
+        initial_query: Query = None
+    ) -> Union[LazyCommand[int], int]:
         primary_keys = inspect(self.model).primary_key
 
         if not primary_keys:
-            raise InvalidQueryError("Your repository model does not have"
-                                    " any primary keys. We cannot use count()")
+            raise InvalidQueryError(
+                "Your repository model does not have any primary keys. We cannot use count()"
+            )
 
         return self.get(
             *specifications,
             lazy=False,
-            query=select(func.count(getattr(self.model, primary_keys[0].name))),
+            initial_query=initial_query or select(func.count(getattr(self.model, primary_keys[0].name))),
         )