adapt flaskr example to sqlalchemy

examples/flaskr/.gitignore

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+venv/
+*.pyc
+instance/
+.pytest_cache/
+.coverage
+htmlcov/
+dist/
+build/
+*.egg-info/
+.idea/

examples/flaskr/LICENSE.rst

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+Copyright 2010 Pallets
+
+Redistribution and use in source and binary forms, with or without
+modification, are permitted provided that the following conditions are
+met:
+
+1.  Redistributions of source code must retain the above copyright
+    notice, this list of conditions and the following disclaimer.
+
+2.  Redistributions in binary form must reproduce the above copyright
+    notice, this list of conditions and the following disclaimer in the
+    documentation and/or other materials provided with the distribution.
+
+3.  Neither the name of the copyright holder nor the names of its
+    contributors may be used to endorse or promote products derived from
+    this software without specific prior written permission.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
+PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED
+TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
+PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
+LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
+NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

examples/flaskr/MANIFEST.in

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+graft flaskr/static
+graft flaskr/templates
+graft tests
+global-exclude *.pyc

examples/flaskr/README.rst

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+Flaskr
+======
+
+The basic blog app built in the Flask `tutorial`_, modified to use
+Flask-SQLAlchemy instead of plain SQL.
+
+.. _tutorial: http://flask.pocoo.org/docs/tutorial/
+
+
+Install
+-------
+
+**Be sure to use the same version of the code as the version of the docs
+you're reading.** You probably want the latest tagged version, but the
+default Git version is the master branch.
+
+.. code-block:: text
+
+    # clone the repository
+    $ git clone https://github.com/pallets/flask-sqlalchemy
+    $ cd flask-sqlalchemy/examples/flaskr
+    # checkout the correct version
+    $ git checkout correct-version-tag
+
+Create a virtualenv and activate it:
+
+.. code-block:: text
+
+    $ python3 -m venv venv
+    $ . venv/bin/activate
+
+Or on Windows cmd:
+
+.. code-block:: text
+
+    $ py -3 -m venv venv
+    $ venv\Scripts\activate.bat
+
+Install Flaskr:
+
+.. code-block:: text
+
+    $ pip install -e .
+
+Or if you are using the master branch, install Flask-SQLAlchemy from
+source before installing Flaskr:
+
+.. code-block:: text
+
+    $ pip install -e ../..
+    $ pip install -e .
+
+
+Run
+---
+
+.. code-block:: text
+
+    $ export FLASK_APP=flaskr
+    $ export FLASK_ENV=development
+    $ flask init-db
+    $ flask run
+
+Or on Windows cmd:
+
+.. code-block:: text
+
+    > set FLASK_APP=flaskr
+    > set FLASK_ENV=development
+    > flask init-db
+    > flask run
+
+Open http://127.0.0.1:5000 in a browser.
+
+
+Test
+----
+
+.. code-block:: text
+
+    $ pip install -e '.[test]'
+    $ pytest
+
+Run with coverage report:
+
+.. code-block:: text
+
+    $ coverage run -m pytest
+    $ coverage report
+    $ coverage html  # open htmlcov/index.html in a browser

examples/flaskr/flaskr/__init__.py

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+import os
+
+import click
+from flask import Flask
+from flask.cli import with_appcontext
+from flask_sqlalchemy import SQLAlchemy
+
+__version__ = (1, 0, 0, "dev")
+
+db = SQLAlchemy()
+
+
+def create_app(test_config=None):
+    """Create and configure an instance of the Flask application."""
+    app = Flask(__name__, instance_relative_config=True)
+
+    # some deploy systems set the database url in the environ
+    db_url = os.environ.get("DATABASE_URL")
+
+    if db_url is None:
+        # default to a sqlite database in the instance folder
+        db_url = "sqlite:///" + os.path.join(app.instance_path, "flaskr.sqlite")
+        # ensure the instance folder exists
+        os.makedirs(app.instance_path, exist_ok=True)
+
+    app.config.from_mapping(
+        # default secret that should be overridden in environ or config
+        SECRET_KEY=os.environ.get("SECRET_KEY", "dev"),
+        SQLALCHEMY_DATABASE_URI=db_url,
+        SQLALCHEMY_TRACK_MODIFICATIONS=False,
+    )
+
+    if test_config is None:
+        # load the instance config, if it exists, when not testing
+        app.config.from_pyfile("config.py", silent=True)
+    else:
+        # load the test config if passed in
+        app.config.update(test_config)
+
+    # initialize Flask-SQLAlchemy and the init-db command
+    db.init_app(app)
+    app.cli.add_command(init_db_command)
+
+    # apply the blueprints to the app
+    from flaskr import auth, blog
+
+    app.register_blueprint(auth.bp)
+    app.register_blueprint(blog.bp)
+
+    # make "index" point at "/", which is handled by "blog.index"
+    app.add_url_rule("/", endpoint="index")
+
+    return app
+
+
+def init_db():
+    db.drop_all()
+    db.create_all()
+
+
+@click.command("init-db")
+@with_appcontext
+def init_db_command():
+    """Clear existing data and create new tables."""
+    init_db()
+    click.echo("Initialized the database.")

examples/flaskr/flaskr/auth.py

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+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 sqlalchemy.ext.hybrid import hybrid_property
+from werkzeug.security import check_password_hash
+from werkzeug.security import generate_password_hash
+
+from flaskr import db
+
+
+class User(db.Model):
+    id = db.Column(db.Integer, primary_key=True)
+    username = db.Column(db.String, unique=True, nullable=False)
+    _password = db.Column("password", db.String, nullable=False)
+
+    @hybrid_property
+    def password(self):
+        return self._password
+
+    @password.setter
+    def password(self, value):
+        """Store the password as a hash for security."""
+        self._password = generate_password_hash(value)
+
+    def check_password(self, value):
+        return check_password_hash(self.password, value)
+
+
+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")
+    g.user = User.query.get(user_id) if user_id is not None else None
+
+
+@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"]
+        error = None
+
+        if not username:
+            error = "Username is required."
+        elif not password:
+            error = "Password is required."
+        elif db.session.query(
+            User.query.filter_by(username=username).exists()
+        ).scalar():
+            error = f"User {username} is already registered."
+
+        if error is None:
+            # the name is available, create the user and go to the login page
+            db.session.add(User(username=username, password=password))
+            db.session.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"]
+        error = None
+        user = User.query.filter_by(username=username).first()
+
+        if user is None:
+            error = "Incorrect username."
+        elif not user.check_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"))