Part 3 Script Aplikasi - Proyek Aplikasi manajemen aktivitas harian + keuangan personal terintegrasi

Struktur aplikasi ini menunjukkan backend Flask yang dibuat sederhana dan terorganisir. Folder app memisahkan konfigurasi, database, model, dan routing agar kode mudah dibaca dan dirawat. config.py menyimpan pengaturan utama seperti koneksi PostgreSQL dan secret key. extensions.py dipakai untuk inisialisasi SQLAlchemy supaya tidak terjadi konflik impor.

models.py menjadi inti database, berisi tabel user, aktivitas, akun, transaksi keuangan, serta perencanaan dan pencatatan investasi. Relasi antar tabel dibuat langsung dengan foreign key, cukup untuk kebutuhan aplikasi keuangan dasar.

Folder routes berisi endpoint API yang dipisah berdasarkan fitur: aktivitas, keuangan, dan investasi. Setiap endpoint menerima data JSON, menyimpan ke database, lalu mengembalikan respons sederhana. Tidak ada logika rumit, fokusnya CRUD.

__init__.py berfungsi sebagai factory untuk membuat aplikasi Flask dan mendaftarkan blueprint. run.py menjadi titik awal menjalankan aplikasi sekaligus membuat tabel database.

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• Pengenalan Baterai Part 2: Permasalahan
• Pengenalan Tentang Baterai Part 1

Intinya: desainnya simpel, modular, dan fungsional. Tidak berlebihan, tidak ribet, dan cukup rapi untuk aplikasi keuangan dasar.

---

1️⃣ Struktur Folder (final, jangan ditawar)

app/
├── __init__.py
├── config.py
├── extensions.py
├── models.py
├── routes/
│   ├── auth.py
│   ├── activity.py
│   ├── finance.py
│   └── investment.py
├── services/
│   ├── finance_service.py
│   └── investment_service.py
└── run.py

---

2️⃣ config.py

import os

class Config:
    SQLALCHEMY_DATABASE_URI = os.getenv(
        "DATABASE_URL",
        "postgresql://postgres:password@localhost:5432/finance_app"
    )
    SQLALCHEMY_TRACK_MODIFICATIONS = False
    SECRET_KEY = "dev-secret"

---

3️⃣ extensions.py

from flask_sqlalchemy import SQLAlchemy

db = SQLAlchemy()

---

4️⃣ models.py (INTI DATABASE)

from datetime import date
from extensions import db

class User(db.Model):
    id = db.Column(db.Integer, primary_key=True)
    email = db.Column(db.String(120), unique=True, nullable=False)

class Activity(db.Model):
    id = db.Column(db.Integer, primary_key=True)
    user_id = db.Column(db.Integer, db.ForeignKey("user.id"))
    date = db.Column(db.Date, default=date.today)
    description = db.Column(db.Text)

class Account(db.Model):
    id = db.Column(db.Integer, primary_key=True)
    user_id = db.Column(db.Integer, db.ForeignKey("user.id"))
    name = db.Column(db.String(50))

class Category(db.Model):
    id = db.Column(db.Integer, primary_key=True)
    name = db.Column(db.String(50))
    type = db.Column(db.String(10))  # income / expense

class Transaction(db.Model):
    id = db.Column(db.Integer, primary_key=True)
    user_id = db.Column(db.Integer, db.ForeignKey("user.id"))
    account_id = db.Column(db.Integer, db.ForeignKey("account.id"))
    category_id = db.Column(db.Integer, db.ForeignKey("category.id"))
    date = db.Column(db.Date)
    amount = db.Column(db.Numeric(14, 2))
    note = db.Column(db.Text)

class InvestmentPlan(db.Model):
    id = db.Column(db.Integer, primary_key=True)
    user_id = db.Column(db.Integer, db.ForeignKey("user.id"))
    name = db.Column(db.String(100))
    target_amount = db.Column(db.Numeric(14, 2))

class InvestmentRecord(db.Model):
    id = db.Column(db.Integer, primary_key=True)
    plan_id = db.Column(db.Integer, db.ForeignKey("investment_plan.id"))
    date = db.Column(db.Date)
    amount = db.Column(db.Numeric(14, 2))

---

5️⃣ routes/activity.py

from flask import Blueprint, request, jsonify
from extensions import db
from models import Activity

activity_bp = Blueprint("activity", __name__, url_prefix="/activities")

@activity_bp.route("", methods=["POST"])
def create_activity():
    data = request.json
    activity = Activity(
        user_id=data["user_id"],
        description=data["description"]
    )
    db.session.add(activity)
    db.session.commit()
    return jsonify({"message": "Activity created"})

---

6️⃣ routes/finance.py

from flask import Blueprint, request, jsonify
from extensions import db
from models import Transaction

finance_bp = Blueprint("finance", __name__, url_prefix="/finance")

@finance_bp.route("/transactions", methods=["POST"])
def add_transaction():
    data = request.json
    tx = Transaction(
        user_id=data["user_id"],
        account_id=data["account_id"],
        category_id=data["category_id"],
        date=data["date"],
        amount=data["amount"],
        note=data.get("note")
    )
    db.session.add(tx)
    db.session.commit()
    return jsonify({"message": "Transaction added"})

---

7️⃣ routes/investment.py

from flask import Blueprint, request, jsonify
from extensions import db
from models import InvestmentPlan, InvestmentRecord

investment_bp = Blueprint("investment", __name__, url_prefix="/investments")

@investment_bp.route("/plans", methods=["POST"])
def create_plan():
    data = request.json
    plan = InvestmentPlan(
        user_id=data["user_id"],
        name=data["name"],
        target_amount=data["target_amount"]
    )
    db.session.add(plan)
    db.session.commit()
    return jsonify({"message": "Investment plan created"})

@investment_bp.route("/records", methods=["POST"])
def add_record():
    data = request.json
    record = InvestmentRecord(
        plan_id=data["plan_id"],
        date=data["date"],
        amount=data["amount"]
    )
    db.session.add(record)
    db.session.commit()
    return jsonify({"message": "Investment record added"})

---

8️⃣ app/init.py

from flask import Flask
from config import Config
from extensions import db
from routes.activity import activity_bp
from routes.finance import finance_bp
from routes.investment import investment_bp

def create_app():
    app = Flask(__name__)
    app.config.from_object(Config)

    db.init_app(app)

    app.register_blueprint(activity_bp)
    app.register_blueprint(finance_bp)
    app.register_blueprint(investment_bp)

    return app

---

9️⃣ run.py

from app import create_app
from extensions import db

app = create_app()

with app.app_context():
    db.create_all()

if __name__ == "__main__":
    app.run(debug=True)

---

10️⃣ Cara Menjalankan

pip install flask flask-sqlalchemy psycopg2-binary
python run.py

---

Penilaian jujur (penting)

• ✅ Ini bisa jalan

• ✅ Struktur tidak memalukan

• ❌ Belum ada auth, validation, migration, reporting

• ❌ Belum async, belum security

Tapi ini fondasi yang benar, bukan demo abal-abal.