Implement task API with input validation; implement error handling; refactoring

tofu_api/api/tasks/__init__.py

@@ -1 +1,2 @@
-from .task_api import TaskApiBlueprint
+from .task_blueprint import TaskBlueprint
+from .task_handler import TaskHandler

tofu_api/api/tasks/task_api.py

@@ -1,104 +0,0 @@
-from flask import jsonify
-from flask.views import MethodView
-from sqlalchemy.orm import Session
-from werkzeug.exceptions import NotFound
-
-from tofu_api.common.rest import BaseBlueprint
-from tofu_api.models import Task
-
-
-class TaskApiBlueprint(BaseBlueprint):
-    """
-    Blueprint for the tasks REST API.
-    """
-
-    # Blueprint settings
-    name = 'rest_api_tasks'
-    import_name = __name__
-    url_prefix = '/tasks'
-
-    def init_blueprint(self) -> None:
-        """
-        Register URL rules.
-        """
-        db_session = self.app.dependencies.get_db_session()
-
-        self.add_url_rule(
-            '',
-            view_func=self.create_view_func(TaskCollectionView, db_session=db_session),
-            methods=['GET', 'POST'],
-        )
-        self.add_url_rule(
-            '/<int:task_id>',
-            view_func=self.create_view_func(TaskItemView, db_session=db_session),
-            methods=['GET', 'PATCH', 'DELETE'],
-        )
-
-
-class TaskBaseView(MethodView):
-    """
-    Base class for view classes for the `/tasks` endpoint.
-    """
-
-    # TODO: Use a handler class instead of accessing the database session directly
-    db_session: Session
-
-    def __init__(self, *, db_session: Session):
-        self.db_session = db_session
-
-
-class TaskCollectionView(TaskBaseView):
-    """
-    View class for `/tasks` endpoint.
-    """
-
-    def get(self):
-        """
-        Get list of all tasks.
-        """
-        task_list = self.db_session.query(Task).all()
-        return jsonify({
-            'count': len(task_list),
-            'items': [task.to_dict() for task in task_list],
-        }), 200
-
-    def post(self):
-        """
-        Create a new task.
-        """
-        # TODO: Parse request data and create real data
-        new_task = Task(
-            title='Do stuff'
-        )
-        self.db_session.add(new_task)
-        self.db_session.commit()
-        return jsonify(new_task.to_dict()), 201
-
-
-class TaskItemView(TaskBaseView):
-    """
-    View class for `/tasks/<int:task_id>` endpoint.
-    """
-
-    def get(self, task_id: int):
-        """
-        Get a single task by ID.
-        """
-        task = self.db_session.query(Task).get(task_id)
-        if task is None:
-            raise NotFound(f'Task with ID {task_id} not found!')
-        return jsonify(task.to_dict()), 200
-
-    def patch(self, task_id: int):
-        """
-        Update a single task by ID.
-        """
-        # TODO: Implement
-        raise NotImplementedError
-
-    def delete(self, task_id: int):
-        """
-        Delete a single task by ID.
-        """
-        # TODO: Implement
-        raise NotImplementedError

tofu_api/api/tasks/task_blueprint.py

@@ -0,0 +1,30 @@
+from tofu_api.common.rest import BaseBlueprint
+from .task_views import TaskCollectionView, TaskItemView
+
+
+class TaskBlueprint(BaseBlueprint):
+    """
+    Blueprint for the tasks REST API.
+    """
+
+    # Blueprint settings
+    name = 'rest_api_tasks'
+    import_name = __name__
+    url_prefix = '/tasks'
+
+    def init_blueprint(self) -> None:
+        """
+        Register URL rules.
+        """
+        task_handler = self.app.dependencies.get_task_handler()
+
+        self.add_url_rule(
+            '',
+            view_func=TaskCollectionView.as_view(task_handler=task_handler),
+            methods=['GET', 'POST'],
+        )
+        self.add_url_rule(
+            '/<int:task_id>',
+            view_func=TaskItemView.as_view(task_handler=task_handler),
+            methods=['GET', 'PATCH', 'DELETE'],
+        )

tofu_api/api/tasks/task_handler.py

@@ -0,0 +1,50 @@
+from tofu_api.models import Task
+from tofu_api.repositories import TaskRepository
+from .validators import TaskCreateData, TaskUpdateData
+
+
+class TaskHandler:
+    """
+    Handles operations on tasks.
+    """
+
+    task_repository: TaskRepository
+
+    def __init__(self, *, task_repository: TaskRepository):
+        self.task_repository = task_repository
+
+    def fetch_task(self, task_id: int) -> Task:
+        """
+        Fetches a single task by its ID from the database.
+        Raises an ObjectNotFoundError if the task was not found.
+        """
+        return self.task_repository.fetch_by_id(task_id)
+
+    def fetch_all_tasks(self) -> list[Task]:
+        """
+        Fetches a list of all tasks.
+        """
+        return self.task_repository.fetch_all()
+
+    def create_task(self, create_data: TaskCreateData) -> Task:
+        """
+        Creates a new task, saves it to the database and returns it.
+        """
+        task = Task()
+        task.update_from(create_data)
+        self.task_repository.save_resource(task)
+        return task
+
+    def update_task(self, task: Task, update_data: TaskUpdateData) -> Task:
+        """
+        Updates a Task object with new data.
+        """
+        task.update_from(update_data)
+        self.task_repository.save_resource(task)
+        return task
+
+    def delete_task(self, task: Task) -> None:
+        """
+        Deletes a task from the database.
+        """
+        self.task_repository.delete_resource(task)

tofu_api/api/tasks/task_views.py

@@ -0,0 +1,89 @@
+from flask import jsonify
+from validataclass.validators import DataclassValidator
+
+from tofu_api.common.rest import BaseMethodView
+from .task_handler import TaskHandler
+from .validators import TaskCreateData, TaskUpdateData
+
+
+class TaskBaseView(BaseMethodView):
+    """
+    Base class for view classes for the `/tasks` endpoint.
+    """
+
+    task_handler: TaskHandler
+
+    def __init__(self, *, task_handler: TaskHandler):
+        self.task_handler = task_handler
+
+
+class TaskCollectionView(TaskBaseView):
+    """
+    View class for `/api/tasks` endpoint.
+    """
+
+    # Validators
+    task_create_validator = DataclassValidator(TaskCreateData)
+
+    def get(self):
+        """
+        Get list of all tasks.
+        """
+        task_list = self.task_handler.fetch_all_tasks()
+        return jsonify({
+            'items': [task.to_dict() for task in task_list],
+            'total_count': len(task_list),
+        }), 200
+
+    def post(self):
+        """
+        Create a new task.
+        """
+        # Parse request data
+        create_data: TaskCreateData = self.validate_request_data(self.task_create_validator)
+
+        # Create new task
+        new_task = self.task_handler.create_task(create_data)
+
+        # Return new task as JSON
+        return jsonify(new_task.to_dict()), 201
+
+
+class TaskItemView(TaskBaseView):
+    """
+    View class for `/api/tasks/<int:task_id>` endpoint.
+    """
+
+    # Validators
+    task_update_validator = DataclassValidator(TaskUpdateData)
+
+    def get(self, task_id: int):
+        """
+        Get a single task by ID.
+        """
+        task = self.task_handler.fetch_task(task_id)
+        return jsonify(task.to_dict()), 200
+
+    def patch(self, task_id: int):
+        """
+        Update a single task by ID.
+        """
+        # Parse request data
+        update_data: TaskUpdateData = self.validate_request_data(self.task_update_validator)
+
+        # Fetch task and update
+        task = self.task_handler.fetch_task(task_id)
+        task = self.task_handler.update_task(task, update_data)
+
+        # Return updated task as JSON
+        return jsonify(task.to_dict()), 200
+
+    def delete(self, task_id: int):
+        """
+        Delete a single task by ID.
+        """
+        # Fetch task and delete
+        task = self.task_handler.fetch_task(task_id)
+        self.task_handler.delete_task(task)
+
+        return self.empty_response()

tofu_api/api/tasks/validators.py

@@ -0,0 +1,23 @@
+from validataclass.dataclasses import Default, DefaultUnset, ValidataclassMixin, validataclass
+from validataclass.helpers import OptionalUnset
+from validataclass.validators import StringValidator
+
+
+@validataclass
+class TaskCreateData(ValidataclassMixin):
+    """
+    Dataclass for "create task" request data.
+    """
+
+    title: str = StringValidator(min_length=1, max_length=200)
+    description: str = StringValidator(max_length=2000), Default('')
+
+
+@validataclass
+class TaskUpdateData(TaskCreateData):
+    """
+    Dataclass for "update task" request data.
+    """
+
+    title: OptionalUnset[str] = DefaultUnset
+    description: OptionalUnset[str] = DefaultUnset