1. 定义路由本质
比如在url.py定义以下路由，浏览器中输入http://192.168.0.1:8000/user/2003-04-21可以访问
意味着此url http://192.168.0.1:8000/user/2003-04-21 和url.py里的路由们做了路由匹配
如果匹配成功找到相应的试图函数
源码解析
ctrl+鼠标左键 点进re_path,会发现
如果re_path = partial(....)
那么上面的url re_path() = partial(), 这里的_path 和Pattern代表什么接着往后看
partial偏函数：
作用：_path()里面规定了要传递一下参数，而path = partial(...)里面传递了Pattern=RegxPatten
那么我们在使用时即不需要再次传递Pattern
点击_path 恍然大悟，_path接收route, view, kwargs, name,Pattern
route view 在url.py已经规定好了, Pattren在partial函数中规定好了
那么这里url.py里的re_path函数就可以写成
partial(_path(route, view, kwargs=None, name=None, Pattern=None), Pattern=RegexPattern)
替换掉route 和 view
partial(_path(r'user/(\d{4})-(\d{2})-(\d{2})', view.user, kwargs=None, name=None, Pattern=None), Pattern=RegexPattern)
因为partial是偏函数,最后路由变成
_path(r'user/(\d{4})-(\d{2})-(\d{2})', view.user, kwargs=None, name=None, Pattern=RegexPattern)
点进_path看看这个函数干啥呢
现在这是我们的路由
re_path(r'user/(\d{4})-(\d{2})-(\d{2})', view.user)就变成了下面这样
URLPattern(Pattern(r'user/(\d{4})-(\d{2})-(\d{2})', name=None, is_endpoint=True), view.user, None, None),
因为规定Pattern = RegxPattern
URLPattern(RegxPattern(r'user/(\d{4})-(\d{2})-(\d{2})', name=None, is_endpoint=True), view.user, None, None),
两个类的关系 URLPattern RegexPattern
URLPattern默认接受四个参数并封装
封装后的
self.pattern = RegxPattern(r'user/(\d{4})-(\d{2})-(\d{2})', name=None, is_endpoint=True）
self.callback = view.user
其他为None
最后到了RegxPattern类，这里会去封装self._regex
上面传递了RegxPattern(r'user/(\d{4})-(\d{2})-(\d{2})', name=None, is_endpoint=True）
那么self._regex= r'user/(\d{4})-(\d{2})-(\d{2})'
两层封装结束,现在
URLPattern.pattern._regex = r'user/(\d{4})-(\d{2})-(\d{2})'
self.callback = view.user
2.路由匹配流程
-启动项目
-请求到来
http://127.0.0.1:8000/user/
与定义好的路由逐一匹配
那么路由是怎么找到的呢
wsgi请求入口
往下找到wsgiHandler函数里的__call__方法，
此函数为类方法入口
environ为每次请求时浏览器携带的参数
request = self.request_class(environ)
因为规定
request_class = WSGIRequest
所以
request = WSGIRequest(environ)
封装好后可以通过request.POST request.GET request.method request.FILES 拿到想要的数据
request.path_info 可以拿到地址
比如 https://192.168.0.1:8000/user/, path_info 可以拿到/user/
下一步通过request 进行函数处理拿到response， 点进get_response
点进get_response发现又进行了_middleware_chain处理
再点 _middleware_chain = handler
往上翻找handler到底是什么
传入的mw_instance
mw_instance = middleware(adapted_handler)
又绕回到上面的adapt_method_mode方法
所以adapted_handler = handler
现在确定handler就是_get_response
现在具体观察这个方法
这里分成两部分查看
1. get_resolver()
进一步查看_get_cached_resolver(urlconf)
URlResolver分析完毕，下面看URLResolver里的resolve方法， 图片注释有误
import_module相当于 from day006 import urls
urls.py被导入之后,patterns = urls.urlpatterns
然后就可进行循环
从最开始的讲解
urls.py里的每一条数据
比如 path('user/(\d{4})-(\d{2})-(\d{2})', view.user)也就等于
URLPattern(RegxPattern(r'user/(\d{4})-(\d{2})-(\d{2})', name=None, is_endpoint=True), view.user, None, None),
每次for pattern做匹配的时候也就是相当于
URLPattern(RegxPattern(r'user/(\d{4})-(\d{2})-(\d{2})', name=None, is_endpoint=True), view.user, None, None),
找到它下面的resolve方法 传入'user/'做验证
这里的resolve就在URLPattern.resolve(new_path)
因为一个re_path() = URLPattern(RegxPattern(r'user/(\d{4})-(\d{2})-(\d{2})', name=None, is_endpoint=True), view.user, None, None),
URLPattern()这里传递的第一个参数为RegxPattern(r'user/(\d{4})-(\d{2})-(\d{2})'
所以self.pattern = RegxPattern(r'user/(\d{4})-(\d{2})-(\d{2})'
这里return的返回值
