Jusene's Blog

Flask框架之RESTful Api

python
字数统计: 879阅读时长: 4 min
2018/01/03 Share

REST

REST是所有Web应用都应该遵守的架构设计指导原则，Representational State Transfer(表现层状态转化)，面向资源是REST最明显的特征，对于同一资源的一组不同的操作，资源是服务器上一个可命名的抽象概念，资源是以名词为核心来组织的，首先关注的是名词。REST要求，必须通过统一接口来对资源执行各种操作。对于每个资源只能执行一组有限的操作。

安装和使用

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pip install flask-restful
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from flask import Flask
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from flask.ext import restful
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app=Flask(__name__)
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api=restful.Api(app)
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class HelloFlask(restful.Resource):
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    def get(self):
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        return {'hello':'flask'}
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api.add_resource(HelloFlask,'/')
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if __name__ == "__main__":
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    app.run(debug=True)

Flask-RESTful提供的最主要的基础就是resources，只要在你的资源上定义方法就能容易地访问多个HTTP方法。

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from flask import Flask,request
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from flask.ext.restful import Resource,Api
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app=Flask(__name__)
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api=Api(app)
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todos={}
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class TodoSimple(Resource):
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    def get(self,todo_id):
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        return {todo_id:todos[todo_id]}
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    def put(self,todo_id):
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        todos[todo_id]=request.form['data']
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        return {todo_id:todos[todo_id]}
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api.add_resource(TodoSimple,'/<string:todo_id>')
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if __name__ == "__main__":
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    app.run(debug=True)
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~]# curl -XPUT http://127.0.0.1:5000/todo1 -d "data=Chagne Me"
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{
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    "todo1": "Change Me"
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}
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~]# curl http://127.0.0.1:5000/todo1
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{
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    "todo1": "Change Me"
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}
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>>> from requests import put,get
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>>> put('http://127.0.0.1:5000/todo2',data={'data':"Remember Me"}).json()
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{'todo2': 'Remember Me'}
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>>> get('http://127.0.0.1:5000/todo2').json()
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{'todo2': 'Remember Me'}

Flask-RESTful支持视图方法多种类型返回值，它将会被转换成一个包含原始 Flask 响应对象的响应，Flask-RESTful 也支持使用多个返回值来设置响应代码和响应头。

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from flask import Flask
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from flask.ext.restful import Resource,Api
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app=Flask(__name__)
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api=Api(app)
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class Default(Resource):
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    def get(self):
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        return {'message':'OK'}
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class Error(Resource):
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    def get(self):
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        return {'error':'fail'},404
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class Header(Resource):
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    def get(self):
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        return {'api':'Restful'},201,{'Server':'Api Server'}
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api.add_resource(Default,'/')
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api.add_resource(Error,'/error')
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api.add_resource(Header,'/header')
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if __name__ == "__main__":
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    app.run(debug=True)

参数解析

Flask能够简单地访问请求数据（比如查询字符串或者POST表单编码的数据），验证表单数据仍然很痛苦，Flask-RESTful内置了支持验证请求数据，它使用了一个类似argparse的库。

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from flask import Flask,request
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from flask.ext.restful import Resource,Api,reqparse
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app=Flask(__name__)
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api=Api(app)
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class Default(Resource):
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    def get(self,arg):
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        return {arg:bands[arg]}
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    def put(self,arg):
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        parser=reqparse.RequestParser()
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        parser.add_argument('rate',type=int,help='Rate must int')
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        args=parser.parse_args()
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        return args
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api.add_resource(Default,'/<string:arg>')
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if __name__ == "__main__":
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    app.run(debug=True)
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~]# curl -XPUT -d 'rate=foo' 127.0.0.1:5000/rate
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{
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    "message": {
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        "rate": "rate must int"
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    }
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}
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~]# curl -XPUT -d 'rate=1000' 127.0.0.1:5000/rate
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{
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    "rate": "1000"
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}

完整例子:

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from flask import Flask
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from flask.ext.restful import reqparse,abort,Api,Resource
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app=Flask(__name__)
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api=Api(app)
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TODOS={
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    'todo1':{'task':'build an API'},
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    'todo2':{'task':'????'},
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    'todo3':{'task':'profit!'},
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}
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def abort_if_todo_doesnt_exist(todo_id):
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    if todo_id not in TODOS:
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        abort(404,message="Todo {} doesn't exist".format(todo_id))
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parser=reqparse.RequestParser()
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parser.add_argument('task',type=str)
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class Todo(Resource):
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    def get(self,todo_id):
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        abort_if_todo_doesnt_exist(todo_id)
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        return TODOS[todo_id]
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    def delete(self,todo_id):
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        abort_if_todo_doesnt_exist(todo_id)
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        del TODOS[todo_id]
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        return '',204
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    def put(self,todo_id):
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        args=parser.parse_args()
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        task={'task':args['task']}
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        TODOS[todo_id]=task
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        return task,201
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class TodoList(Resource):
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    def get(self):
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        return TODOS
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    def post(self):
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        args=parser.parse_args()
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        todo_id=int(max(TODOS.keys()).lstrip('todo'))+1
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        todo_id='todo%i' % todo_id 
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        TODOS[todo_id]={'task':args['task']}
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        return TODOS[todo_id],201
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api.add_resource(TodoList,'/todos')
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api.add_resource(Todo,'/todos/<todo_id>')
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if __name__ == "__main__":
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    app.run()

原文作者：Zhang Jusene

原文链接：http://jusene.github.io/2018/01/03/flask-restapi/

发表日期：January 3rd 2018, 3:44:13 pm

更新日期：November 30th 2019, 1:54:24 am

版权声明：本文采用知识共享署名-非商业性使用 4.0 国际许可协议进行许可

CATALOG
  1. 1. REST
  2. 2. 安装和使用
  3. 3. 参数解析
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