add token response

.env.example

@@ -0,0 +1,2 @@
+JWT_SECRET=your_jwt_secret_key_here
+JWT_ALGORITHM=HS256

.gitignore

@@ -1,3 +1,4 @@
 __pycache__
 .venv
 database.db
+.env

database.py

@@ -1,49 +1,104 @@
-from models import User
-from passlib.context import CryptContext
+from models import User, TokenResponse
+from settings import settings
+from fastapi import HTTPException, status, Request
 import sqlite3
-import jwt
-import datetime
+import security
 
-JWT_SECRET = "secret"
 
-connection = sqlite3.connect('database.db')
-connection.row_factory = sqlite3.Row
-cursor = connection.cursor()
+def connect() -> (sqlite3.Connection, sqlite3.Cursor):
+    """Connects to the database and returns the connection and cursor."""
+    connection = sqlite3.connect('database.db')
+    connection.row_factory = sqlite3.Row
+    cursor = connection.cursor()
+
+    return connection, cursor
+
+
+connection, cursor = connect()
 
-password_context = CryptContext(schemes=["sha256_crypt"], deprecated="auto")
 
 def init() -> None:
-    # create users table
-     cursor.execute('''
-            CREATE TABLE IF NOT EXISTS users (
-                id INTEGER PRIMARY KEY,
-                name TEXT NOT NULL UNIQUE,
-                password TEXT NOT NULL
-            )
-        ''')
+    """Initializes the database."""
+
+    # Create users table
+    cursor.execute('''
+    CREATE TABLE IF NOT EXISTS users (
+        id INTEGER PRIMARY KEY,
+        name TEXT NOT NULL UNIQUE,
+        password TEXT NOT NULL
+    )
+    ''')
+
+    # Create logs table
+    cursor.execute('''
+    CREATE TABLE IF NOT EXISTS logs (
+        id INTEGER PRIMARY KEY,
+        user_id INTEGER NOT NULL,
+        calories DOUBLE NOT NULL,
+        description TEXT,
+        timestamp DATETIME DEFAULT CURRENT_TIMESTAMP,
+        FOREIGN KEY (user_id) REFERENCES users (id)
+    )
+    ''')
+
 
 def close() -> None:
-     connection.close()
+    """Closes the database connection."""
+    connection.close()
 
 
 def register(user: User) -> None:
-     password = password_context.hash(user.password)
-     cursor.execute("INSERT INTO users (name, password) VALUES (?, ?)", (user.name, password))
-     connection.commit()
+    """Registers a new user in the database."""
+    try:
+        cursor.execute(
+            "INSERT INTO users (name, password) VALUES (?, ?)",
+            (user.name,
+             security.hash_password(user.password)))
+        connection.commit()
+    except sqlite3.IntegrityError:
+        raise HTTPException(
+            status_code=status.HTTP_400_BAD_REQUEST,
+            detail="User already exists"
+        )
+
+
+def get_user_by_token(request: Request) -> User:
+    """Retrieves a user from the database using a JWT token."""
+
+    payload = security.decode_jwt(
+        request.headers.get("Authorization"))
+
+    if not payload:
+        raise HTTPException(
+            status_code=status.HTTP_401_UNAUTHORIZED,
+            detail="Not authenticated"
+        )
+
+    connection, cursor = connect()
+    cursor.execute(
+        "SELECT id, name, password FROM users WHERE id = ?", (payload["id"],))
+    row = cursor.fetchone()
+    connection.close()
+
+    if not row:
+        raise HTTPException(
+            status_code=status.HTTP_401_UNAUTHORIZED,
+            detail="Not authenticated"
+        )
+
+    return User(**row)
+
 
 def login(user: User) -> str:
-     cursor.execute("SELECT id, name, password FROM users WHERE name = ?", (user.name,))
-     row = cursor.fetchone()
+    """Logs in a user and returns a JWT token."""
+    cursor.execute(
+        "SELECT id, name, password FROM users WHERE name = ?", (user.name,))
+    row = cursor.fetchone()
 
-     if not row:
-          raise Exception('User not found')
-     if not password_context.verify(user.password, row["password"]):
-          raise Exception('Invalid password')
+    if not row or not security.verify_password(user.password, row["password"]):
+        raise HTTPException(
+            status_code=status.HTTP_401_UNAUTHORIZED,
+            detail="Invalid credentials"
+        )
 
-     exp = datetime.datetime.now(datetime.timezone.utc) + datetime.timedelta(hours=1)
-     payload = {
-          "id": row["id"],
-          "exp": exp
-     }
-     
-     return jwt.encode(payload=payload, key=JWT_SECRET, algorithm="HS256")
+    return TokenResponse(token=security.sign_jwt(row))

format.sh

@@ -0,0 +1,6 @@
+#!/usr/bin/env bash
+which autopep8 &> /dev/null || { echo "autopep8 not found, please install it."; exit 1; }
+
+autopep8 --in-place --aggressive --aggressive --recursive --exclude .venv,.git,__pycache__ .
+
+echo "Code formatted with autopep8."

main.py

@@ -1,7 +1,15 @@
-from fastapi import FastAPI
+from fastapi import FastAPI, Depends, status
 from contextlib import asynccontextmanager
 import database
 import models
+import logging
+
+logging.basicConfig(
+    level=logging.INFO,
+    format="%(asctime)s - %(name)s - %(levelname)s - %(message)s",
+    datefmt="%Y-%m-%d %H:%M:%S",
+)
+
 
 @asynccontextmanager
 async def lifespan(app: FastAPI):
@@ -12,15 +20,17 @@ async def lifespan(app: FastAPI):
 app = FastAPI(lifespan=lifespan)
 
 
-@app.get("/")
-async def root():
-    return {"message": "Hello World"}
+@app.get("/me")
+async def me(user: models.User = Depends(database.get_user_by_token)):
+    return user
 
-@app.post("/users")
+
+@app.post("/register", status_code=status.HTTP_201_CREATED)
 async def register(user: models.User):
     database.register(user)
     return user
 
+
 @app.post("/login")
 async def login(user: models.User):
     return database.login(user)

models.py

@@ -1,5 +1,10 @@
 from pydantic import BaseModel
 
+
 class User(BaseModel):
     name: str
     password: str
+
+
+class TokenResponse(BaseModel):
+    token: str

requirements.txt

@@ -0,0 +1,5 @@
+fastapi[standard]==0.121.2
+passlib==1.7.4
+pyjwt==2.10.1
+pydantic-settings==2.12.0
+autopep8==2.3.2

security.py

@@ -0,0 +1,61 @@
+from passlib.context import CryptContext
+from settings import settings
+import jwt
+import datetime
+import logging
+
+password_context = CryptContext(schemes=["sha256_crypt"], deprecated="auto")
+logger = logging.getLogger(__name__)
+
+
+def hash_password(password: str) -> str:
+    """Hashes a plain text password."""
+    return password_context.hash(password)
+
+
+def verify_password(plain_password: str, hashed_password: str) -> bool:
+    """Verifies a plain text password against a hashed password."""
+    return password_context.verify(plain_password, hashed_password)
+
+
+def sign_jwt(row: dict) -> str:
+    """Signs a JWT token with the given payload."""
+    exp = datetime.datetime.now(
+        datetime.timezone.utc) + datetime.timedelta(hours=1)
+
+    payload = {
+        "id": row["id"],
+        "exp": exp
+    }
+
+    return jwt.encode(
+        payload,
+        key=settings.jwt_secret,
+        algorithm=settings.jwt_algorithm
+    )
+
+
+def decode_jwt(token: str | None) -> dict | None:
+    """Decodes a JWT token and returns the payload."""
+    if not token or not token.startswith("Bearer "):
+        logger.warning(
+            "No token provided or token does not start with 'Bearer '")
+        return None
+
+    try:
+        payload = jwt.decode(
+            token.replace("Bearer ", ""),
+            key=settings.jwt_secret,
+            algorithms=[settings.jwt_algorithm]
+        )
+
+        return payload
+    except jwt.ExpiredSignatureError:
+        logger.warning("Token has expired")
+        return None
+    except jwt.InvalidTokenError:
+        logger.warning("Invalid token")
+        return None
+
+    logger.warning("Unexpected error in token decoding")
+    return None

settings.py

@@ -0,0 +1,12 @@
+from pydantic_settings import BaseSettings, SettingsConfigDict
+
+
+class Settings(BaseSettings):
+    model_config = SettingsConfigDict(
+        env_file='.env', env_file_encoding='utf-8')
+
+    jwt_secret: str
+    jwt_algorithm: str
+
+
+settings = Settings()