Description of a simple example under the flask framework (including reverse routing url_for)

Example 1

Referenced from

# -*- coding: utf-8 -*-  
#路由与反向路由  
from flask import Flask  
from flask import request  
from flask import url_for  

app=Flask(__name__)  

#@app.route为路由，"/"是根目录  
@app.route('/')  
def hello_world():  
    return 'hello world'  

#用methods来指定传输方式  
@app.route('/user',methods=['GET','POST'])  
def hello_user():  
    return 'hello user'  

#参数传递，这里指定为"id"  
@app.route('/user/<id>')  
def hello_userid(id):  
    return 'hello userid:'+id  

#根据键值对返回id  
@app.route('/query_user')  
def query_user():  
    id=request.args.get('id')  
    return 'query_user:'+id  

#反向函数:通过视图反导出URL地址
#返回的是“query_url:/query_user”，通过url_for通过end point访问query_user  
@app.route('/query_url')  
def quer_url():  
    return 'query_url:'+url_for('query_user')  

if __name__=='__main__':  
    app.run(debug=True,port=7777)  

reverse routing

URL**–>endpoint–>**viewfunction

reverse routing

https://www.cnblogs.com/captainmeng/p/8572833.html

Example 2

More

from flask import Flask
from flask.ext.restful import reqparse, abort, Api, Resource

app = Flask(__name__)
api = Api(app)

TODOS = {
    'todo1': {'task': 'build an API'},
    'todo2': {'task': '?????'},
    'todo3': {'task': 'profit!'},
}


def abort_if_todo_doesnt_exist(todo_id):
    if todo_id not in TODOS:
        abort(404, message="Todo {} doesn't exist".format(todo_id))

parser = reqparse.RequestParser()
parser.add_argument('task', type=str)


# Todo
#   show a single todo item and lets you delete them
class Todo(Resource):
    def get(self, todo_id):
        abort_if_todo_doesnt_exist(todo_id)
        return TODOS[todo_id]

    def delete(self, todo_id):
        abort_if_todo_doesnt_exist(todo_id)
        del TODOS[todo_id]
        return '', 204

    def put(self, todo_id):
        args = parser.parse_args()
        task = {'task': args['task']}
        TODOS[todo_id] = task
        return task, 201


# TodoList
#   shows a list of all todos, and lets you POST to add new tasks
class TodoList(Resource):
    def get(self):
        return TODOS

    def post(self):
        args = parser.parse_args()
        todo_id = int(max(TODOS.keys()).lstrip('todo')) + 1
        todo_id = 'todo%i' % todo_id
        TODOS[todo_id] = {'task': args['task']}
        return TODOS[todo_id], 201

##
## Actually setup the Api resource routing here
##
api.add_resource(TodoList, '/todos')
api.add_resource(Todo, '/todos/<todo_id>')


if __name__ == '__main__':
    app.run(debug=True)