章：数据库 35 为了设置 Flask、扩展或是我们程序本身的一些行为，我们需要设置和定义一些配 置变量。Flask 提供了一个统一的接口来写入和获取这些配置变 量： Flask.config 字典。配置变量的名称必须使用大写，写入配置的语句一般 会放到扩展类实例化语句之前。 下面写入了一个 SQLALCHEMY_DATABASE_URI 变量来告诉 SQLAlchemy 数据库连 config['SQLALCHEMY_DATABASE_URI'] = 'sqlite:////' + os.path. join(app.root_path, 'data.db') 注意 这个配置变量的最后一个单词是 URI，而不是 URL。 对于这个变量值，不同的 DBMS 有不同的格式，对于 SQLite 来说，这个值的格式 如下： sqlite:////数据库文件的绝对地址 数据库文件一般放到项目根目录即可， sqlite3 作为后缀。 另外，如果你使用 Windows 系统，上面的 URI 前缀部分需要写入三个斜线（即 sqlite:/// ）。在本书的示例程序代码里，做了一些兼容性处理，另外还新设 置了一个配置变量，实际的代码如下： 第 5 章：数据库 36 import os import sys from flask import Flask WIN = sys.platform.startswith('win')

Nested Field Extending Flask-RESTful Content Negotiation Custom Fields & Inputs Response Formats Resource Method Decorators Custom Error Handlers Intermediate Usage Project Structure Use With Blueprints from flask_restful import Resource, Api app = Flask(__name__) api = Api(app) class HelloWorld(Resource): def get(self): return {'hello': 'world'} api.add_resource(HelloWorld, '/') if __name__ defining methods on your resource. A basic CRUD resource for a todo application (of course) looks like this: from flask import Flask, request from flask_restful import Resource, Api app = Flask(__name__)

Flask from flask_restful import Resource, Api app = Flask(__name__) api = Api(app) class HelloWorld(Resource): def get(self): return {'hello': 'world'} api.add_resource(HelloWorld, '/') if __name__ defining methods on your resource. A basic CRUD resource for a todo application (of course) looks like this: from flask import Flask, request from flask_restful import Resource, Api app = Flask(__name__) TodoSimple(Resource): def get(self, todo_id): return {todo_id: todos[todo_id]} def put(self, todo_id): todos[todo_id] = request.form['data'] return {todo_id: todos[todo_id]} api.add_resource(TodoSimple

Nested Field Extending Flask-RESTful Content Negotiation Custom Fields & Inputs Response Formats Resource Method Decorators Custom Error Handlers Intermediate Usage Project Structure Use With Blueprints from flask_restful import Resource, Api app = Flask(__name__) api = Api(app) class HelloWorld(Resource): def get(self): return {'hello': 'world'} api.add_resource(HelloWorld, '/') if __name__ defining methods on your resource. A basic CRUD resource for a todo application (of course) looks like this: from flask import Flask, request from flask_restful import Resource, Api app = Flask(__name__)

Nested Field Extending Flask-RESTful Content Negotiation Custom Fields & Inputs Response Formats Resource Method Decorators Custom Error Handlers Intermediate Usage Project Structure Use With Blueprints from flask_restful import Resource, Api app = Flask(__name__) api = Api(app) class HelloWorld(Resource): def get(self): return {'hello': 'world'} api.add_resource(HelloWorld, '/') if __name__ defining methods on your resource. A basic CRUD resource for a todo application (of course) looks like this: from flask import Flask, request from flask_restful import Resource, Api app = Flask(__name__)

Flask from flask_restful import Resource, Api app = Flask(__name__) api = Api(app) class HelloWorld(Resource): def get(self): return {'hello': 'world'} api.add_resource(HelloWorld, '/') if __name__ defining methods on your resource. A basic CRUD resource for a todo application (of course) looks like this: from flask import Flask, request from flask_restful import Resource, Api app = Flask(__name__) TodoSimple(Resource): def get(self, todo_id): return {todo_id: todos[todo_id]} def put(self, todo_id): todos[todo_id] = request.form['data'] return {todo_id: todos[todo_id]} api.add_resource(TodoSimple

Flask from flask_restful import Resource, Api app = Flask(__name__) api = Api(app) class HelloWorld(Resource): def get(self): return {'hello': 'world'} api.add_resource(HelloWorld, '/') if __name__ defining methods on your resource. A basic CRUD resource for a todo application (of course) looks like this: from flask import Flask, request from flask_restful import Resource, Api app = Flask(__name__) TodoSimple(Resource): def get(self, todo_id): return {todo_id: todos[todo_id]} def put(self, todo_id): todos[todo_id] = request.form['data'] return {todo_id: todos[todo_id]} api.add_resource(TodoSimple

Nested Field Extending Flask-RESTful Content Negotiation Custom Fields & Inputs Response Formats Resource Method Decorators Custom Error Handlers Intermediate Usage Project Structure Use With Blueprints from flask_restful import Resource, Api app = Flask(__name__) api = Api(app) class HelloWorld(Resource): def get(self): return {'hello': 'world'} api.add_resource(HelloWorld, '/') if __name__ defining methods on your resource. A basic CRUD resource for a todo application (of course) looks like this: from flask import Flask, request from flask_restful import Resource, Api app = Flask(__name__)

Flask from flask_restful import Resource, Api app = Flask(__name__) api = Api(app) class HelloWorld(Resource): def get(self): return {'hello': 'world'} api.add_resource(HelloWorld, '/') if __name__ defining methods on your resource. A basic CRUD resource for a todo application (of course) looks like this: from flask import Flask, request from flask_restful import Resource, Api app = Flask(__name__) TodoSimple(Resource): def get(self, todo_id): return {todo_id: todos[todo_id]} def put(self, todo_id): todos[todo_id] = request.form['data'] return {todo_id: todos[todo_id]} api.add_resource(TodoSimple

commands to the db.py file: flaskr/db.py 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') existing data and create new tables.""" init_db() click.echo('Initialized the database.') open_resource() opens a file relative to the flaskr package, which is useful since you won’t necessarily know open_instance_resource(). Example usage for both: filename = os.path.join(app.instance_path, 'application.cfg') with open(filename) as f: config = f.read() # or via open_instance_resource: with app