flask框架(三)——路由系统route转换成add_url_rule及源码分析

这节我们不用@app.route来写路由,而是通过add_url_rule

传统写法  (<int:nid>传递int类型参数,endpoint是取别名)

@app.route('/detail/<int:nid>',methods=['GET'],endpoint='detail')

默认转换器

DEFAULT_CONVERTERS = {
    'default':          UnicodeConverter,
    'string':           UnicodeConverter,
    'any':              AnyConverter,
    'path':             PathConverter,
    'int':              IntegerConverter,
    'float':            FloatConverter,
    'uuid':             UUIDConverter,
}

路由系统本质(源码分析)

从@app.route的route入手

源码app.py (从下面的源码可以看出route本质就是add_url_rule.这里的self就是实例化对象,也就是之前的app)

    def route(self, rule, **options):

        def decorator(f):
            endpoint = options.pop("endpoint", None)
            self.add_url_rule(rule, endpoint, f, **options)
            return f

        return decorator

然后跳转到add_url_rule

@setupmethod
    def add_url_rule(
        self,
        rule,  #视图函数路由
        endpoint=None,  #取别名(非必填)
        view_func=None,  #这个就是上一个跳转过来的f,就是视图函数名(必填)
        provide_automatic_options=None,
        **options
    ):
   
        if endpoint is None:  #如果endpoint(别名)没填,就进入_endpoint_from_view_func看看
            endpoint = _endpoint_from_view_func(view_func)
        options["endpoint"] = endpoint
        methods = options.pop("methods", None)
if methods is None: methods = getattr(view_func, "methods", None) or ("GET",) if isinstance(methods, string_types): raise TypeError( "Allowed methods have to be iterables of strings, " 'for example: @app.route(..., methods=["POST"])' ) methods = set(item.upper() for item in methods) # Methods that should always be added required_methods = set(getattr(view_func, "required_methods", ())) if provide_automatic_options is None: provide_automatic_options = getattr( view_func, "provide_automatic_options", None ) if provide_automatic_options is None: if "OPTIONS" not in methods: provide_automatic_options = True required_methods.add("OPTIONS") else: provide_automatic_options = False # Add the required methods now. methods |= required_methods rule = self.url_rule_class(rule, methods=methods, **options) rule.provide_automatic_options = provide_automatic_options self.url_map.add(rule) if view_func is not None: old_func = self.view_functions.get(endpoint) if old_func is not None and old_func != view_func: raise AssertionError( "View function mapping is overwriting an " "existing endpoint function: %s" % endpoint ) self.view_functions[endpoint] = view_func

进入_endpoint_from_view_func看看是怎么取别名的 ()

assert view_func is not None, "expected view func if endpoint is not provided."
return view_func.__name__

第一句话是永远不是执行的,看第二句,取名就是视图函数名,这里就是login

取别名使用方法(url_for): 访问login路径,返回123

from flask import Flask,url_for
app=Flask(__name__)
app.debug=True
def index():
return '123'
app.add_url_rule('/index',view_func=index,endpoint='sb',methods=['POST',"GET"])


def login():
real_url=url_for("sb")
return real_url
app.add_url_rule('/login',view_func=index,methods=['POST',"GET"])
if __name__ == '__main__': 
  app.run()

add_url_rule参数总结:

rule:必填参数,就是跳转路由
endpoint:非必填参数,如果不填就是视图函数名。如果设置了endpoint,就在视图函数中通过url_for使用,不能设置重复,用于反向生成URL,即: url_for('名称')
view_func:也就是请求该路由时,相应的视图函数名称
methods:设置请求方式,默认是get请求,如:['GET','POST']

add_url_rule额外参数:

defaults = None, 默认值, 当URL中无参数,函数需要参数时,使用defaults = {'k': 'v'}

#对URL最后的 / 符号是否严格要求,False是非严格模式,True严格模式,默认是严格模式
strict_slashes = None
  '''
        @app.route('/index', strict_slashes=False)
        #访问http://www.xx.com/index/ 或http://www.xx.com/index均可
        @app.route('/index', strict_slashes=True)
        #仅访问http://www.xx.com/index
    '''
#重定向到指定地址
redirect_to = None, 
    '''
        @app.route('/index/<int:nid>', redirect_to='/home/<nid>')
    '''

总结代码示例:

from  flask import Flask,url_for
app=Flask(__name__)
app.debug=True

def login(nid):
    print(type(nid),nid)
    return "ojbk_login"
app.add_url_rule('/login/<string:nid>',view_func=login,endpoint="sb",methods=['POST',"GET"])

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

也可以设置有名参数:添加数据类型的有名参数,通过视图函数传递参数

原文地址:https://www.cnblogs.com/wangcuican/p/11838264.html