First chapter

flaskr/__init__.py

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+import os
+
+from flask import Flask
+
+
+def create_app(test_config=None):
+    # create and configure the app
+    app = Flask(__name__, instance_relative_config=True)
+    app.config.from_mapping(
+        SECRET_KEY='dev',
+        DATABASE=os.path.join(app.instance_path, 'flaskr.sqlite'),
+    )
+
+    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.from_mapping(test_config)
+
+    # ensure the instance folder exists
+    try:
+        os.makedirs(app.instance_path)
+    except OSError:
+        pass
+
+    # a simple page that says hello
+    @app.route('/hello')
+    def hello():
+        return 'Hello, World!'
+
+    return app

flaskr/db.py

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+import sqlite3
+
+import click
+from flask import current_app, g
+from flask.cli import with_appcontext
+
+
+def get_db():
+    if 'db' not in g:
+        g.db = sqlite3.connect(
+            current_app.config['DATABASE'],
+            detect_types=sqlite3.PARSE_DECLTYPES
+        )
+        g.db.row_factory = sqlite3.Row
+
+    return g.db
+
+
+def close_db(e=None):
+    db = g.pop('db', None)
+
+    if db is not None:
+        db.close()
+
+def init_db():
+    db = get_db()
+
+    with current_app.open_resource('schema.sql') as f:
+        db.executescript(f.read().decode('utf8'))
+
+
+@click.command('init-db')
+@with_appcontext
+def init_db_command():
+    """Clear the existing data and create new tables."""
+    init_db()
+    click.echo('Initialized the database.')
+
+def init_app(app):
+    app.teardown_appcontext(close_db)
+    app.cli.add_command(init_db_command)

flaskr/schema.sql

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+DROP TABLE IF EXISTS user;
+DROP TABLE IF EXISTS post;
+
+CREATE TABLE user (
+  id INTEGER PRIMARY KEY AUTOINCREMENT,
+  username TEXT UNIQUE NOT NULL,
+  password TEXT NOT NULL
+);
+
+CREATE TABLE post (
+  id INTEGER PRIMARY KEY AUTOINCREMENT,
+  author_id INTEGER NOT NULL,
+  created TIMESTAMP NOT NULL DEFAULT CURRENT_TIMESTAMP,
+  title TEXT NOT NULL,
+  body TEXT NOT NULL,
+  FOREIGN KEY (author_id) REFERENCES user (id)
+);