flask探索-1

1. 安装

   pip install -U Flask

   Successfully built itsdangerous MarkupSafe
   Installing collected packages: MarkupSafe, Jinja2, itsdangerous, Werkzeug, click, Flask
   Successfully installed Flask-1.0.2 Jinja2-2.10 MarkupSafe-1.0 Werkzeug-0.14.1 click-6.7 itsdangerous-0.24
   

   看起来都用了这几个包

   MarkupSafe
   Jinja2
   itsdangerous
   Werkzeug
   click
   Flask

   是干啥的暂且不知道,接下来跟着官网第一个示例走你

   from flask import Flask
   
   
   #创建了一个Flask的实例
   
   app = Flask(__name__)
   
   
   @app.route('/')
   def hello():
       return "hello world"

   来看看route这个带参装饰器的实现

   def route(self, rule, **options):
       def decorator(f):
           #key: 要删除的键/值对所对应的键
           #default: 可选参数，给定键不在字典中时必须设置，否者会报错(没有默认值)，此时返回default值
           endpoint = options.pop('endpoint', None)
           self.add_url_rule(rule, endpoint, f, **options)
           return f
       return decorator
   

   add_url_rule的实现

   @setupmethod
   def add_url_rule(self, rule, endpoint=None, view_func=None,
                    provide_automatic_options=None, **options):
       """
       :param rule: the URL rule as string
       :param endpoint: the endpoint for the registered URL rule.  Flask
                        itself assumes the name of the view function as
                        endpoint
   
       :param options:
       the options to be forwarded to the underlying :class:`~werkzeug.routing.Rule` object.  
       A change to Werkzeug is handling of method options.
       methods is a list of methods this rule should be limited
       to (``GET``, ``POST`` etc.)"""
       if endpoint is None:
           endpoint = _endpoint_from_view_func(view_func)
       options['endpoint'] = endpoint
       methods = options.pop('methods', None)
   

   @app.route('/')
   def hello():
       return "hello world"
   
   #就相当于
   
   add_url_rule(rule='/',view_func=hello)
   
   #假如入我们把接受的请求方法改为get,应该就是这么写
   
   
   #注意methods is a list of methods
   
   @app.route('/',methods=['GET'])
   def hello():
       return "hello world"
   """
   不过有句注释这么说来着 
   By default a rulejust listens for ``GET`` 
   所以啊,这种情况下上面的method可以省略
   
   那如果我想接收一个post请求呢
   """
   
   @app.route('/post',methods=['POST'])
   def post():
       return "post method\n"
   

   测试下
   

   当然也可以走一个,既可以接受POST,又可以接受GET的请求.如下

   @app.route('/double',methods=['POST','GET'])
   def double():
       if request.method == 'POST':
           return 'post something'
       elif request.method == 'GET':
           return 'get something'

   测试下