源码粗略分析
'''
globals:
_request_ctx_stack = LocalStack()
_app_ctx_stack = LocalStack()
current_app = LocalProxy(_find_app)
request = LocalProxy(partial(_lookup_req_object, "request"))
session = LocalProxy(partial(_lookup_req_object, "session"))
g = LocalProxy(partial(_lookup_app_object, "g"))
1 run_simple(host, port, self, **options),self是app,执行self()，Flask里面的__call__
2 在__call__里面执行的return self.wsgi_app(environ, start_response)，把执行结果返回，
environ请求相关的, start_response响应相关的
3 self.wsgi_app(environ, start_response)的源码：
def wsgi_app(self, environ, start_response):
#得到一个RequestContext的对象，这对象里面有包含了request和session
ctx = self.request_context(environ)
error = None
try:
try:
ctx.push()
response = self.full_dispatch_request()
except Exception as e:
error = e
response = self.handle_exception(e)
except: # noqa: B001
error = sys.exc_info()[1]
raise
return response(environ, start_response)
finally:
if self.should_ignore_error(error):
error = None
ctx.auto_pop(error)
3.1 执行 ctx = self.request_context(environ):environ请求相关的：的源码
return RequestContext(self, environ) self是app,environ请求相关的
3.1.1RequestContext(self, environ)实例化一个RequestContext对象
def __init__(self, app, environ, request=None, session=None):
self.app = app
if request is None:
request = app.request_class(environ)
self.request = request
self.url_adapter = None
try:
self.url_adapter = app.create_url_adapter(self.request)
except HTTPException as e:
self.request.routing_exception = e
self.flashes = None
self.session = session
3.1总结：ctx = self.request_context(environ)以后ctx为RequestContext对象，这个对象有request,session
3.2 ctx.push()里面执行了
_request_ctx_stack.push(self)：self是ctx
3.2.1_request_ctx_stack这个是一个全局变量是LocalStack()的对象
_request_ctx_stack.push(self)就是执行LocalStack里面的push方法
3.2.1.1 LocalStack里面的push方法,obj参数是ctx
def push(self, obj):
rv = getattr(self._local, "stack", None)
if rv is None:
self._local.stack = rv = []
#把obj,也就是ctx存到了LOCAL对象中的storage,存的格式为： storage={"执行id":{'stack':[ctx,]}}
rv.append(obj)
return rv
3.2.1.2 rv = getattr(self._local, "stack", None)这个self._local是LOCAL对象
3.3 response = self.full_dispatch_request()，这里是响应函数与请求扩展
def full_dispatch_request(self):
#第一请求的函数,before_first_request里面的所有函数
self.try_trigger_before_first_request_functions()
try:
#信号
request_started.send(self)
#before_request执行的结果，如果这个里面有返回值，后面的befor_request都不会执行
#如果 rv = self.preprocess_request()，rv为None,才会执行self.dispatch_request()
#也就响应函数
rv = self.preprocess_request()
if rv is None:
# 真正的响应函数，如果上面的before_request没有返回值就执行它，并拿到rv这个返回值
rv = self.dispatch_request()
except Exception as e:
rv = self.handle_user_exception(e)
#请求之后的函数，也就是after_request的函数
return self.finalize_request(rv)
3.4 请求结束后执行ctx.auto_pop(error)把它在LOCAL对象中删除.删除的是ctx
