Current File : //usr/share/doc/python3-flask/examples/flaskr/auth.py
import functools
from flask import Blueprint
from flask import flash
from flask import g
from flask import redirect
from flask import render_template
from flask import request
from flask import session
from flask import url_for
from werkzeug.security import check_password_hash
from werkzeug.security import generate_password_hash
from flaskr.db import get_db
bp = Blueprint("auth", __name__, url_prefix="/auth")
def login_required(view):
"""View decorator that redirects anonymous users to the login page."""
@functools.wraps(view)
def wrapped_view(**kwargs):
if g.user is None:
return redirect(url_for("auth.login"))
return view(**kwargs)
return wrapped_view
@bp.before_app_request
def load_logged_in_user():
"""If a user id is stored in the session, load the user object from
the database into ``g.user``."""
user_id = session.get("user_id")
if user_id is None:
g.user = None
else:
g.user = (
get_db().execute("SELECT * FROM user WHERE id = ?", (user_id,)).fetchone()
)
@bp.route("/register", methods=("GET", "POST"))
def register():
"""Register a new user.
Validates that the username is not already taken. Hashes the
password for security.
"""
if request.method == "POST":
username = request.form["username"]
password = request.form["password"]
db = get_db()
error = None
if not username:
error = "Username is required."
elif not password:
error = "Password is required."
elif (
db.execute("SELECT id FROM user WHERE username = ?", (username,)).fetchone()
is not None
):
error = f"User {username} is already registered."
if error is None:
# the name is available, store it in the database and go to
# the login page
db.execute(
"INSERT INTO user (username, password) VALUES (?, ?)",
(username, generate_password_hash(password)),
)
db.commit()
return redirect(url_for("auth.login"))
flash(error)
return render_template("auth/register.html")
@bp.route("/login", methods=("GET", "POST"))
def login():
"""Log in a registered user by adding the user id to the session."""
if request.method == "POST":
username = request.form["username"]
password = request.form["password"]
db = get_db()
error = None
user = db.execute(
"SELECT * FROM user WHERE username = ?", (username,)
).fetchone()
if user is None:
error = "Incorrect username."
elif not check_password_hash(user["password"], password):
error = "Incorrect password."
if error is None:
# store the user id in a new session and return to the index
session.clear()
session["user_id"] = user["id"]
return redirect(url_for("index"))
flash(error)
return render_template("auth/login.html")
@bp.route("/logout")
def logout():
"""Clear the current session, including the stored user id."""
session.clear()
return redirect(url_for("index"))
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