From dc814b68cbf1666da923dc20d79965f817b0a7b6 Mon Sep 17 00:00:00 2001
From: CarloGarcellano <202480047@psu.palawan.edu.ph>
Date: Fri, 29 May 2026 20:07:15 +0800
Subject: [PATCH] Add REST API with full CRUD operations and unit tests

---
 README.md   | 114 ++++++++++++++++++++++---------------
 api.py      |  82 +++++++++++++++++++++++++++
 app.py      |   9 ++-
 test_api.py | 159 ++++++++++++++++++++++++++++++++++++++++++++++++++++
 4 files changed, 317 insertions(+), 47 deletions(-)
 create mode 100644 api.py
 create mode 100644 test_api.py

diff --git a/README.md b/README.md
index e2a98cb..0e8d8a7 100644
--- a/README.md
+++ b/README.md
@@ -1,45 +1,69 @@
-Simple Flask Todo App using SQLAlchemy and SQLite database.
-
-For styling [semantic-ui](https://semantic-ui.com/) is used.
-
-### Setup
-Create project with virtual environment
-
-```console
-$ mkdir myproject
-$ cd myproject
-$ python3 -m venv venv
-```
-
-Activate it
-```console
-$ . venv/bin/activate
-```
-
-or on Windows
-```console
-venv\Scripts\activate
-```
-
-Install Flask
-```console
-$ pip install Flask
-$ pip install Flask-SQLAlchemy
-```
-
-Set environment variables in terminal
-```console
-$ export FLASK_APP=app.py
-$ export FLASK_ENV=development
-```
-
-or on Windows
-```console
-$ set FLASK_APP=app.py
-$ set FLASK_ENV=development
-```
-
-Run the app
-```console
-$ flask run
-```
+# Flask Todo App — with REST API
+
+This is a fork of [patrickloeber/flask-todo](https://github.com/patrickloeber/flask-todo), a simple Todo web application built with Flask and SQLAlchemy.
+
+## What is the original app?
+
+The original app is a simple Todo list web application. You open it in your browser, type a task, and click Add. You can also mark tasks as complete or delete them. But all of that only works through the browser — there is no way for another program to talk to it.
+
+## What did I add?
+
+I added a REST API. This means other programs (like Postman, a mobile app, or another website) can now interact with the todos by sending HTTP requests and receiving JSON responses — without touching the browser at all.
+
+This is useful because:
+- A mobile app could use the API to sync todos
+- Another service could automatically create or delete todos
+- Developers can test the app without opening a browser
+
+## How does it work?
+
+The API has 5 routes that cover full CRUD operations:
+
+- GET /api/todos — returns a list of all todos as JSON
+- GET /api/todos/id — returns one specific todo by its ID
+- POST /api/todos — creates a new todo (send a title in the request body)
+- PUT /api/todos/id — updates an existing todo (change title or complete status)
+- DELETE /api/todos/id — deletes a todo permanently
+
+All responses are in JSON format. The API also handles errors properly:
+- 200 means the request was successful
+- 201 means a new todo was successfully created
+- 400 means the request was missing something or had bad data
+- 404 means the todo ID does not exist
+
+## Files I Added
+
+### api.py
+Contains all 5 API routes with full CRUD functionality and error handling.
+Uses Flask Blueprint to keep the API separate from the main app code.
+
+### test_api.py
+Contains 18 unit tests written with pytest.
+Tests cover all CRUD operations with both positive and negative test cases.
+Positive tests check that things work correctly.
+Negative tests check that errors are handled properly (missing data, wrong ID, etc.)
+
+## How to Run
+
+1. Clone and switch to the feature branch:
+   git clone https://github.com/CarloGarcellano/flask-todo.git
+   cd flask-todo
+   git checkout feature/rest-api
+
+2. Install dependencies:
+   pip install flask flask-sqlalchemy pytest pytest-cov
+
+3. Run the app:
+   python app.py
+
+4. Visit the app in your browser:
+   http://127.0.0.1:5000
+
+5. Test the API:
+   http://127.0.0.1:5000/api/todos
+
+6. Run the unit tests:
+   pytest test_api.py -v
+
+## Original Repository
+https://github.com/patrickloeber/flask-todo
\ No newline at end of file
diff --git a/api.py b/api.py
new file mode 100644
index 0000000..27e060d
--- /dev/null
+++ b/api.py
@@ -0,0 +1,82 @@
+from flask import Blueprint, jsonify, request
+
+api = Blueprint("api", __name__)
+
+def get_db_and_todo():
+    from app import db, Todo, app
+    return db, Todo, app
+
+@api.route("/api/todos", methods=["GET"])
+def get_todos():
+    db, Todo, app = get_db_and_todo()
+    with app.app_context():
+        todos = Todo.query.all()
+        return jsonify([
+            {"id": todo.id, "title": todo.title, "complete": todo.complete}
+            for todo in todos
+        ]), 200
+
+@api.route("/api/todos/<int:todo_id>", methods=["GET"])
+def get_todo(todo_id):
+    db, Todo, app = get_db_and_todo()
+    with app.app_context():
+        todo = Todo.query.get(todo_id)
+        if todo is None:
+            return jsonify({"error": "Todo not found"}), 404
+        return jsonify({
+            "id": todo.id,
+            "title": todo.title,
+            "complete": todo.complete
+        }), 200
+
+@api.route("/api/todos", methods=["POST"])
+def create_todo():
+    db, Todo, app = get_db_and_todo()
+    data = request.get_json()
+    if not data or "title" not in data or not data["title"].strip():
+        return jsonify({"error": "A 'title' field is required"}), 400
+    with app.app_context():
+        new_todo = Todo(title=data["title"].strip(), complete=False)
+        db.session.add(new_todo)
+        db.session.commit()
+        return jsonify({
+            "id": new_todo.id,
+            "title": new_todo.title,
+            "complete": new_todo.complete
+        }), 201
+
+@api.route("/api/todos/<int:todo_id>", methods=["PUT"])
+def update_todo(todo_id):
+    db, Todo, app = get_db_and_todo()
+    data = request.get_json()
+    if not data:
+        return jsonify({"error": "No data provided"}), 400
+    with app.app_context():
+        todo = Todo.query.get(todo_id)
+        if todo is None:
+            return jsonify({"error": "Todo not found"}), 404
+        if "title" in data:
+            if not data["title"].strip():
+                return jsonify({"error": "Title cannot be empty"}), 400
+            todo.title = data["title"].strip()
+        if "complete" in data:
+            if not isinstance(data["complete"], bool):
+                return jsonify({"error": "'complete' must be true or false"}), 400
+            todo.complete = data["complete"]
+        db.session.commit()
+        return jsonify({
+            "id": todo.id,
+            "title": todo.title,
+            "complete": todo.complete
+        }), 200
+
+@api.route("/api/todos/<int:todo_id>", methods=["DELETE"])
+def delete_todo(todo_id):
+    db, Todo, app = get_db_and_todo()
+    with app.app_context():
+        todo = Todo.query.get(todo_id)
+        if todo is None:
+            return jsonify({"error": "Todo not found"}), 404
+        db.session.delete(todo)
+        db.session.commit()
+        return jsonify({"message": f"Todo {todo_id} deleted successfully"}), 200
\ No newline at end of file
diff --git a/app.py b/app.py
index 4b6ccca..1885646 100644
--- a/app.py
+++ b/app.py
@@ -45,6 +45,11 @@ def delete(todo_id):
     db.session.commit()
     return redirect(url_for("home"))
 
+
+from api import api
+app.register_blueprint(api)
+
 if __name__ == "__main__":
-    db.create_all()
-    app.run(debug=True)
+    with app.app_context():
+        db.create_all()
+    app.run(debug=True)
\ No newline at end of file
diff --git a/test_api.py b/test_api.py
new file mode 100644
index 0000000..edf6580
--- /dev/null
+++ b/test_api.py
@@ -0,0 +1,159 @@
+import pytest
+import json
+from app import app, db, Todo
+
+
+@pytest.fixture
+def client():
+    app.config["TESTING"] = True
+    app.config["SQLALCHEMY_DATABASE_URI"] = "sqlite:///:memory:"
+    with app.test_client() as client:
+        with app.app_context():
+            db.create_all()
+            yield client
+            db.drop_all()
+
+
+def make_todo(client, title="Test Todo"):
+    return client.post(
+        "/api/todos",
+        data=json.dumps({"title": title}),
+        content_type="application/json"
+    )
+
+
+class TestGetAllTodos:
+    def test_get_todos_empty(self, client):
+        db.session.query(Todo).delete()
+        db.session.commit()
+        response = client.get("/api/todos")
+        assert response.status_code == 200
+        assert response.get_json() == []
+
+    def test_get_todos_with_items(self, client):
+        make_todo(client, "Buy milk")
+        make_todo(client, "Walk the dog")
+        response = client.get("/api/todos")
+        assert response.status_code == 200
+        assert len(response.get_json()) == 2
+
+    def test_get_todos_correct_fields(self, client):
+        make_todo(client, "Check fields")
+        todo = client.get("/api/todos").get_json()[0]
+        assert "id" in todo
+        assert "title" in todo
+        assert "complete" in todo
+
+
+class TestGetOneTodo:
+    def test_get_existing_todo(self, client):
+        created = make_todo(client, "Read a book").get_json()
+        response = client.get(f"/api/todos/{created['id']}")
+        assert response.status_code == 200
+        assert response.get_json()["title"] == "Read a book"
+
+    def test_get_nonexistent_todo(self, client):
+        response = client.get("/api/todos/9999")
+        assert response.status_code == 404
+        assert "error" in response.get_json()
+
+
+class TestCreateTodo:
+    def test_create_todo(self, client):
+        response = make_todo(client, "Go for a run")
+        assert response.status_code == 201
+        assert response.get_json()["title"] == "Go for a run"
+
+    def test_create_todo_missing_title(self, client):
+        response = client.post(
+            "/api/todos",
+            data=json.dumps({}),
+            content_type="application/json"
+        )
+        assert response.status_code == 400
+
+    def test_create_todo_empty_title(self, client):
+        response = client.post(
+            "/api/todos",
+            data=json.dumps({"title": "   "}),
+            content_type="application/json"
+        )
+        assert response.status_code == 400
+
+    def test_create_todo_no_body(self, client):
+        response = client.post("/api/todos", content_type="application/json")
+        assert response.status_code == 400
+
+
+class TestUpdateTodo:
+    def test_update_title(self, client):
+        created = make_todo(client, "Old title").get_json()
+        response = client.put(
+            f"/api/todos/{created['id']}",
+            data=json.dumps({"title": "New title"}),
+            content_type="application/json"
+        )
+        assert response.status_code == 200
+        assert response.get_json()["title"] == "New title"
+
+    def test_update_complete(self, client):
+        created = make_todo(client, "Finish homework").get_json()
+        response = client.put(
+            f"/api/todos/{created['id']}",
+            data=json.dumps({"complete": True}),
+            content_type="application/json"
+        )
+        assert response.status_code == 200
+        assert response.get_json()["complete"] is True
+
+    def test_update_nonexistent(self, client):
+        response = client.put(
+            "/api/todos/9999",
+            data=json.dumps({"title": "Ghost"}),
+            content_type="application/json"
+        )
+        assert response.status_code == 404
+
+    def test_update_no_body(self, client):
+        created = make_todo(client, "Some todo").get_json()
+        response = client.put(
+            f"/api/todos/{created['id']}",
+            content_type="application/json"
+        )
+        assert response.status_code == 400
+
+    def test_update_empty_title(self, client):
+        created = make_todo(client, "Valid todo").get_json()
+        response = client.put(
+            f"/api/todos/{created['id']}",
+            data=json.dumps({"title": ""}),
+            content_type="application/json"
+        )
+        assert response.status_code == 400
+
+    def test_update_wrong_complete_type(self, client):
+        created = make_todo(client, "Type test").get_json()
+        response = client.put(
+            f"/api/todos/{created['id']}",
+            data=json.dumps({"complete": "yes"}),
+            content_type="application/json"
+        )
+        assert response.status_code == 400
+
+
+class TestDeleteTodo:
+    def test_delete_todo(self, client):
+        created = make_todo(client, "Delete me").get_json()
+        response = client.delete(f"/api/todos/{created['id']}")
+        assert response.status_code == 200
+        assert "deleted" in response.get_json()["message"].lower()
+
+    def test_deleted_todo_gone(self, client):
+        created = make_todo(client, "Temporary").get_json()
+        client.delete(f"/api/todos/{created['id']}")
+        response = client.get(f"/api/todos/{created['id']}")
+        assert response.status_code == 404
+
+    def test_delete_nonexistent(self, client):
+        response = client.delete("/api/todos/9999")
+        assert response.status_code == 404
\ No newline at end of file