为什么引入web框架
web应用的本质
- 浏览器发送一个HTTP请求；
- 服务器收到请求，生成一个HTML文档；
- 服务器把HTML文档作为HTTP响应的Body发送给浏览器；
- 浏览器收到HTTP响应，从HTTP Body取出HTML文档并显示；
涉及的问题
- 解析http请求
- 找到对应的处理函数
- 生成并发送http响应
web框架工作流程
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中间件
- 中间件是请求或者应用开始和结束时注入代码的机制
- 常见的web中间件： 鉴权、打印log、session、统计信息、处理数据库连接 等等
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image
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golang http 服务端编程
- golang 的net/http包提供了http编程的相关接口，封装了内部TCP连接和报文解析的复杂琐碎的细节
go c.serve(ctx)最终会启动goroutine处理请求 - 使用者只需要和
http.request和http.ResponseWriter两个对象交互就行(也就是一个struct 实现net/http包中的Handler interface中的 ServeHttp方法 )
//E:\Go\src\net\http\server.go +82
type Handler interface {
ServeHTTP(ResponseWriter, *Request)
}
//纯 net.http包的server方法
package main
import (
"io"
"net/http"
)
type helloHandler struct{}
func (h *helloHandler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
w.Write([]byte("Hello, world!"))
}
func main() {
http.Handle("/", &helloHandler{})
http.ListenAndServe(":12345", nil)
}
//////////////////////////////////////////////////////////////////
import (
"net/http"
)
type Handle struct{}
func (h Handle) ServeHTTP(response http.ResponseWriter, request *http.Request) {
switch request.URL.Path {
case "/info":
response.Write([]byte("info"))
default:
}
}
func main() {
http.ListenAndServe(":8888", Handle{})
}
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net/http 的另外一个重要的概念 ，ServeMux （多路传输）：ServeMux 可以注册多了 URL 和 handler 的对应关系，并自动把请求转发到对应的 handler 进行处理
-
// 下面看一个带路由的http server package main import ( "io" "net/http" ) func helloHandler(w http.ResponseWriter, r *http.Request) { io.WriteString(w, "Hello, world!\n") } func echoHandler(w http.ResponseWriter, r *http.Request) { io.WriteString(w, r.URL.Path) } func main() { mux := http.NewServeMux() mux.HandleFunc("/hello", helloHandler) mux.HandleFunc("/", echoHandler) http.ListenAndServe(":12345", mux) } // 其实ServeMux 也实现了Handler的ServeHTTP方法所以也是Handler接口 //E:\Go\src\net\http\server.go 2382 func (mux *ServeMux) ServeHTTP(w ResponseWriter, r *Request) { if r.RequestURI == "*" { if r.ProtoAtLeast(1, 1) { w.Header().Set("Connection", "close") } w.WriteHeader(StatusBadRequest) return } h, _ := mux.Handler(r) h.ServeHTTP(w, r) } // E:\Go\src\net\http\server.go +2219可以看到 net/http包中的 基于map 路由查找 // Find a handler on a handler map given a path string. // Most-specific (longest) pattern wins. func (mux *ServeMux) match(path string) (h Handler, pattern string) { // Check for exact match first. v, ok := mux.m[path] if ok { return v.h, v.pattern } // Check for longest valid match. var n = 0 for k, v := range mux.m { if !pathMatch(k, path) { continue } if h == nil || len(k) > n { n = len(k) h = v.h pattern = v.pattern } } return }image.gif
golang web框架 GIN golang gin web框架
//gin框架初始化的流程
1.初始化engine
2.注册中间件
3.注册路由
//响应流程
1.路由，找到handle
2.将请求和响应用Context包装起来供业务代码使用
3.依次调用中间件和处理函数
4.输出结果
//gin 里面最重要的两个数据结构
//1.Context在中间件中传递本次请求的各种数据、管理流程，进行响应
//2.Engine gin 引擎，是框架的实例，它包含多路复用器，中间件和配置设置
// 下面看下open-falcon-api中的实际应用
//open-falcon-api里面注册路由和中间件
//E:\go_path\src\github.com\open-falcon\falcon-plus\modules\api\app\controller\graph\graph_routes.go
// 首先注册/api/v1/开头的path的路由组
// 然后Use 一个auth的中间件 ，作用是检查token
// 这个组后面的所有path 都使用这个中间件
// 也就是访问 /graph/endpoint 时会过 3个中间件(log recovery auth )+一个EndpointRegexpQuery处理函数
//
func Routes(r *gin.Engine) {
db = config.Con()
authapi := r.Group("/api/v1")
authapi.Use(utils.AuthSessionMidd)
authapi.GET("/graph/endpointobj", EndpointObjGet)
authapi.GET("/graph/endpoint", EndpointRegexpQuery)
authapi.GET("/graph/endpoint_counter", EndpointCounterRegexpQuery)
authapi.POST("/graph/history", QueryGraphDrawData)
authapi.POST("/graph/lastpoint", QueryGraphLastPoint)
authapi.POST("/graph/info", QueryGraphItemPosition)
authapi.DELETE("/graph/endpoint", DeleteGraphEndpoint)
authapi.DELETE("/graph/counter", DeleteGraphCounter)
grfanaapi := r.Group("/api")
grfanaapi.GET("/v1/grafana", GrafanaMainQuery)
grfanaapi.GET("/v1/grafana/metrics/find", GrafanaMainQuery)
grfanaapi.POST("/v1/grafana/render", GrafanaRender)
grfanaapi.GET("/v1/grafana/render", GrafanaRender)
}
func AuthSessionMidd(c *gin.Context) {
auth, err := h.SessionChecking(c)
if !viper.GetBool("skip_auth") {
if err != nil || auth != true {
log.Debugf("error: %v, auth: %v", err, auth)
c.Set("auth", auth)
h.JSONR(c, http.StatusUnauthorized, err)
c.Abort()
return
}
}
c.Set("auth", auth)
}
// E:\go_path\src\github.com\open-falcon\falcon-plus\vendor\github.com\gin-gonic\gin\context.go +715 最后会调用这里的Render方法
// Render writes the response headers and calls render.Render to render data.
func (c *Context) Render(code int, r render.Render) {
c.Status(code)
if !bodyAllowedForStatus(code) {
r.WriteContentType(c.Writer)
c.Writer.WriteHeaderNow()
return
}
if err := r.Render(c.Writer); err != nil {
panic(err)
}
}
// 可以看到这里的bind 是在gin在解析请求payload是否和函数中要求的struct一致
// E:\go_path\src\github.com\open-falcon\falcon-plus\vendor\github.com\gin-gonic\gin\context.go +504
// bind会根据请求中的Content-Type header判断是json 还是xml
// 并且根据struct中的tag通过反射解析payload
// Bind checks the Content-Type to select a binding engine automatically,
// Depending the "Content-Type" header different bindings are used:
// "application/json" --> JSON binding
// "application/xml" --> XML binding
// otherwise --> returns an error.
// It parses the request's body as JSON if Content-Type == "application/json" using JSON or XML as a JSON input.
// It decodes the json payload into the struct specified as a pointer.
// It writes a 400 error and sets Content-Type header "text/plain" in the response if input is not valid.
func (c *Context) Bind(obj interface{}) error {
b := binding.Default(c.Request.Method, c.ContentType())
return c.MustBindWith(obj, b)
}
type APIEndpointObjGetInputs struct {
Endpoints []string `json:"endpoints" form:"endpoints"`
Deadline int64 `json:"deadline" form:"deadline"`
}
func EndpointObjGet(c *gin.Context) {
inputs := APIEndpointObjGetInputs{
Deadline: 0,
}
if err := c.Bind(&inputs); err != nil {
h.JSONR(c, badstatus, err)
return
}
if len(inputs.Endpoints) == 0 {
h.JSONR(c, http.StatusBadRequest, "endpoints missing")
return
}
var result []m.Endpoint = []m.Endpoint{}
dt := db.Graph.Table("endpoint").
Where("endpoint in (?) and ts >= ?", inputs.Endpoints, inputs.Deadline).
Scan(&result)
if dt.Error != nil {
h.JSONR(c, http.StatusBadRequest, dt.Error)
return
}
endpoints := []map[string]interface{}{}
for _, r := range result {
endpoints = append(endpoints, map[string]interface{}{"id": r.ID, "endpoint": r.Endpoint, "ts": r.Ts})
}
h.JSONR(c, endpoints)
}
//E:\go_path\src\github.com\open-falcon\falcon-plus\modules\api\main.go +78
//初始化gin
routes := gin.Default()
//E:\go_path\src\github.com\open-falcon\falcon-plus\vendor\github.com\gin-gonic\gin\gin.go +148
// Default returns an Engine instance with the Logger and Recovery middleware already attached.
func Default() *Engine {
debugPrintWARNINGDefault()
engine := New()
engine.Use(Logger(), Recovery())
return engine
}
//E:\go_path\src\github.com\open-falcon\falcon-plus\vendor\github.com\gin-gonic\gin\gin.go +119
// new方法 返回一个不带中间件的 单例engine ，并且把context 放在池中
func New() *Engine {
debugPrintWARNINGNew()
engine := &Engine{
RouterGroup: RouterGroup{
Handlers: nil,
basePath: "/",
root: true,
},
FuncMap: template.FuncMap{},
RedirectTrailingSlash: true,
RedirectFixedPath: false,
HandleMethodNotAllowed: false,
ForwardedByClientIP: true,
AppEngine: defaultAppEngine,
UseRawPath: false,
UnescapePathValues: true,
MaxMultipartMemory: defaultMultipartMemory,
trees: make(methodTrees, 0, 9),
delims: render.Delims{Left: "{{", Right: "}}"},
secureJsonPrefix: "while(1);",
}
engine.RouterGroup.engine = engine
engine.pool.New = func() interface{} {
return engine.allocateContext()
}
return engine
}
//E:\go_path\src\github.com\open-falcon\falcon-plus\modules\api\app\controller\routes.go
//r.Run(port) 最后调用的是 net.http.ListenAndServe
func (engine *Engine) Run(addr ...string) (err error) {
defer func() { debugPrintError(err) }()
address := resolveAddress(addr)
debugPrint("Listening and serving HTTP on %s\n", address)
err = http.ListenAndServe(address, engine)
return
}
//E:\Go\src\net\http\server.go +2686
func (sh serverHandler) ServeHTTP(rw ResponseWriter, req *Request) {
handler := sh.srv.Handler
if handler == nil {
handler = DefaultServeMux
}
if req.RequestURI == "*" && req.Method == "OPTIONS" {
handler = globalOptionsHandler{}
}
handler.ServeHTTP(rw, req)
}
//E:\go_path\src\github.com\open-falcon\falcon-plus\vendor\github.com\gin-gonic\gin\gin.go +321
//我们可以看到 在gin中实现了ServeHTTP方法 net.http.Handler
// ServeHTTP conforms to the http.Handler interface.
// 这里使用sync.pool cache context数据结构，避免频繁GC，每次使用都初始化
//一个struct实现了 interface中的方法 就说明这个struct是这个类型
func (engine *Engine) ServeHTTP(w http.ResponseWriter, req *http.Request) {
c := engine.pool.Get().(*Context)
c.writermem.reset(w)
c.Request = req
c.reset()
engine.handleHTTPRequest(c)
engine.pool.Put(c)
}
// gin 里面处理请求的核心方法
// 根据一些配置去 压缩前缀树 radix.tree中找到对应的handleChain 然后执行
// 注意这句handlers, params, tsr := root.getValue(path, c.Params, unescape)
// 路由查找的过程是 从基数树的根节点一直匹配到和请求一致的节点找到对应的handlerchain
// 注册路由 E:\go_path\src\github.com\open-falcon\falcon-plus\vendor\github.com\gin-gonic\gin\gin.go +243
// 从下面的addRoute方法中可以看到gin 为每个HttpMethod GET POST PUT DELETE都注册了一颗tree
// 并且有priority 即最长的路径优先匹配
/*
func (engine *Engine) addRoute(method, path string, handlers HandlersChain) {
assert1(path[0] == '/', "path must begin with '/'")
assert1(method != "", "HTTP method can not be empty")
assert1(len(handlers) > 0, "there must be at least one handler")
debugPrintRoute(method, path, handlers)
root := engine.trees.get(method)
if root == nil {
root = new(node)
engine.trees = append(engine.trees, methodTree{method: method, root: root})
}
root.addRoute(path, handlers)
}
*/
func (engine *Engine) handleHTTPRequest(c *Context) {
httpMethod := c.Request.Method
path := c.Request.URL.Path
unescape := false
if engine.UseRawPath && len(c.Request.URL.RawPath) > 0 {
path = c.Request.URL.RawPath
unescape = engine.UnescapePathValues
}
// Find root of the tree for the given HTTP method
t := engine.trees
for i, tl := 0, len(t); i < tl; i++ {
if t[i].method != httpMethod {
continue
}
root := t[i].root
// Find route in tree
handlers, params, tsr := root.getValue(path, c.Params, unescape)
if handlers != nil {
c.handlers = handlers
c.Params = params
c.Next()
c.writermem.WriteHeaderNow()
return
}
if httpMethod != "CONNECT" && path != "/" {
if tsr && engine.RedirectTrailingSlash {
redirectTrailingSlash(c)
return
}
if engine.RedirectFixedPath && redirectFixedPath(c, root, engine.RedirectFixedPath) {
return
}
}
break
}
if engine.HandleMethodNotAllowed {
for _, tree := range engine.trees {
if tree.method == httpMethod {
continue
}
if handlers, _, _ := tree.root.getValue(path, nil, unescape); handlers != nil {
c.handlers = engine.allNoMethod
serveError(c, http.StatusMethodNotAllowed, default405Body)
return
}
}
}
c.handlers = engine.allNoRoute
serveError(c, http.StatusNotFound, default404Body)
}
image.gif
python django （django框架复杂，先简单看一下）
# 入口文件
def execute_from_command_line(argv=None):
"""
A simple method that runs a ManagementUtility.
"""
utility = ManagementUtility(argv)
utility.execute()
def execute(self):
"""
Given the command-line arguments, figure out which subcommand is being
run, create a parser appropriate to that command, and run it.
"""
try:
subcommand = self.argv[1]
except IndexError:
subcommand = 'help' # Display help if no arguments were given.
# Preprocess options to extract --settings and --pythonpath.
# These options could affect the commands that are available, so they
# must be processed early.
parser = CommandParser(usage='%(prog)s subcommand [options] [args]', add_help=False, allow_abbrev=False)
parser.add_argument('--settings')
parser.add_argument('--pythonpath')
parser.add_argument('args', nargs='*') # catch-all
try:
options, args = parser.parse_known_args(self.argv[2:])
handle_default_options(options)
except CommandError:
pass # Ignore any option errors at this point.
try:
settings.INSTALLED_APPS
except ImproperlyConfigured as exc:
self.settings_exception = exc
except ImportError as exc:
self.settings_exception = exc
if settings.configured:
# Start the auto-reloading dev server even if the code is broken.
# The hardcoded condition is a code smell but we can't rely on a
# flag on the command class because we haven't located it yet.
if subcommand == 'runserver' and '--noreload' not in self.argv:
try:
autoreload.check_errors(django.setup)()
except Exception:
# The exception will be raised later in the child process
# started by the autoreloader. Pretend it didn't happen by
# loading an empty list of applications.
apps.all_models = defaultdict(OrderedDict)
apps.app_configs = OrderedDict()
apps.apps_ready = apps.models_ready = apps.ready = True
# Remove options not compatible with the built-in runserver
# (e.g. options for the contrib.staticfiles' runserver).
# Changes here require manually testing as described in
# #27522.
_parser = self.fetch_command('runserver').create_parser('django', 'runserver')
_options, _args = _parser.parse_known_args(self.argv[2:])
for _arg in _args:
self.argv.remove(_arg)
# In all other cases, django.setup() is required to succeed.
else:
django.setup()
self.autocomplete()
if subcommand == 'help':
if '--commands' in args:
sys.stdout.write(self.main_help_text(commands_only=True) + '\n')
elif not options.args:
sys.stdout.write(self.main_help_text() + '\n')
else:
self.fetch_command(options.args[0]).print_help(self.prog_name, options.args[0])
# Special-cases: We want 'django-admin --version' and
# 'django-admin --help' to work, for backwards compatibility.
elif subcommand == 'version' or self.argv[1:] == ['--version']:
sys.stdout.write(django.get_version() + '\n')
elif self.argv[1:] in (['--help'], ['-h']):
sys.stdout.write(self.main_help_text() + '\n')
else:
self.fetch_command(subcommand).run_from_argv(self.argv)
#C:\Users\Administrator\AppData\Local\Programs\Python\Python37\Lib\site-packages\django\core\management\__init__.py +301
'''
#1.fetch_command 最终会调用C:\Users\Administrator\AppData\Local\Programs\Python\Python37\Lib\site-packages\django\core\management\__init__.py 的find_commands()
最终会找到 django\core\management\commands 下面的所有的command
check
compilemessages
createcachetable
dbshell
diffsettings
dumpdata
flush
inspectdb
loaddata
makemessages
makemigrations
migrate
runserver
sendtestemail
shell
showmigrations
sqlflush
sqlmigrate
sqlsequencereset
squashmigrations
startapp
startproject
test
testserver
2\. run_from_argv 调 execute() 再调用handle()
'''
# 最常用的runserver
#C:\Users\Administrator\AppData\Local\Programs\Python\Python37\Lib\site-packages\django\core\management\commands\runserver.py +
# execute()-->handle()-->run()-->inner_run()-->get_wsgi_application() #WSGIHandler 在这里加载中间件
# C:\Users\Administrator\AppData\Local\Programs\Python\Python37\Lib\site-packages\django\core\handlers\wsgi.py
class WSGIHandler(base.BaseHandler):
request_class = WSGIRequest
def __init__(self, *args, **kwargs):
super().__init__(*args, **kwargs)
self.load_middleware()
def __call__(self, environ, start_response):
set_script_prefix(get_script_name(environ))
signals.request_started.send(sender=self.__class__, environ=environ)
request = self.request_class(environ)
response = self.get_response(request)
response._handler_class = self.__class__
status = '%d %s' % (response.status_code, response.reason_phrase)
response_headers = [
*response.items(),
*(('Set-Cookie', c.output(header='')) for c in response.cookies.values()),
]
start_response(status, response_headers)
if getattr(response, 'file_to_stream', None) is not None and environ.get('wsgi.file_wrapper'):
response = environ['wsgi.file_wrapper'](response.file_to_stream)
return response
def inner_run(self, *args, **options):
# If an exception was silenced in ManagementUtility.execute in order
# to be raised in the child process, raise it now.
autoreload.raise_last_exception()
threading = options['use_threading']
# 'shutdown_message' is a stealth option.
shutdown_message = options.get('shutdown_message', '')
quit_command = 'CTRL-BREAK' if sys.platform == 'win32' else 'CONTROL-C'
self.stdout.write("Performing system checks...\n\n")
self.check(display_num_errors=True)
# Need to check migrations here, so can't use the
# requires_migrations_check attribute.
self.check_migrations()
now = datetime.now().strftime('%B %d, %Y - %X')
self.stdout.write(now)
self.stdout.write((
"Django version %(version)s, using settings %(settings)r\n"
"Starting development server at %(protocol)s://%(addr)s:%(port)s/\n"
"Quit the server with %(quit_command)s.\n"
) % {
"version": self.get_version(),
"settings": settings.SETTINGS_MODULE,
"protocol": self.protocol,
"addr": '[%s]' % self.addr if self._raw_ipv6 else self.addr,
"port": self.port,
"quit_command": quit_command,
})
try:
handler = self.get_handler(*args, **options)
run(self.addr, int(self.port), handler,
ipv6=self.use_ipv6, threading=threading, server_cls=self.server_cls)
except socket.error as e:
# Use helpful error messages instead of ugly tracebacks.
ERRORS = {
errno.EACCES: "You don't have permission to access that port.",
errno.EADDRINUSE: "That port is already in use.",
errno.EADDRNOTAVAIL: "That IP address can't be assigned to.",
}
try:
error_text = ERRORS[e.errno]
except KeyError:
error_text = e
self.stderr.write("Error: %s" % error_text)
# Need to use an OS exit because sys.exit doesn't work in a thread
os._exit(1)
except KeyboardInterrupt:
if shutdown_message:
self.stdout.write(shutdown_message)
sys.exit(0)
# C:\Users\Administrator\AppData\Local\Programs\Python\Python37\Lib\site-packages\django\core\handlers\base.py
class BaseHandler:
_view_middleware = None
_template_response_middleware = None
_exception_middleware = None
_middleware_chain = None
def load_middleware(self):
"""
Populate middleware lists from settings.MIDDLEWARE.
Must be called after the environment is fixed (see __call__ in subclasses).
"""
self._view_middleware = []
self._template_response_middleware = []
self._exception_middleware = []
handler = convert_exception_to_response(self._get_response)
for middleware_path in reversed(settings.MIDDLEWARE):
middleware = import_string(middleware_path)
try:
mw_instance = middleware(handler)
except MiddlewareNotUsed as exc:
if settings.DEBUG:
if str(exc):
logger.debug('MiddlewareNotUsed(%r): %s', middleware_path, exc)
else:
logger.debug('MiddlewareNotUsed: %r', middleware_path)
continue
if mw_instance is None:
raise ImproperlyConfigured(
'Middleware factory %s returned None.' % middleware_path
)
if hasattr(mw_instance, 'process_view'):
self._view_middleware.insert(0, mw_instance.process_view)
if hasattr(mw_instance, 'process_template_response'):
self._template_response_middleware.append(mw_instance.process_template_response)
if hasattr(mw_instance, 'process_exception'):
self._exception_middleware.append(mw_instance.process_exception)
handler = convert_exception_to_response(mw_instance)
# We only assign to this when initialization is complete as it is used
# as a flag for initialization being complete.
self._middleware_chain = handler
#get_handler 函数最终会返回一个 WSGIHandler 的实例。WSGIHandler 类只实现了 def __call__(self, environ, start_response) , 使它本身能够成为 WSGI 中的应用程序, 并且实现 __call__ 能让类的行为跟函数一样。
class WSGIHandler(base.BaseHandler):
request_class = WSGIRequest
def __init__(self, *args, **kwargs):
super().__init__(*args, **kwargs)
self.load_middleware()
def __call__(self, environ, start_response):
set_script_prefix(get_script_name(environ))
signals.request_started.send(sender=self.__class__, environ=environ)
request = self.request_class(environ)
response = self.get_response(request)
response._handler_class = self.__class__
status = '%d %s' % (response.status_code, response.reason_phrase)
response_headers = [
*response.items(),
*(('Set-Cookie', c.output(header='')) for c in response.cookies.values()),
]
start_response(status, response_headers)
if getattr(response, 'file_to_stream', None) is not None and environ.get('wsgi.file_wrapper'):
response = environ['wsgi.file_wrapper'](response.file_to_stream)
return response
# C:\Users\Administrator\AppData\Local\Programs\Python\Python37\Lib\socketserver.py + 215
def serve_forever(self, poll_interval=0.5):
"""
处理一个http请求直到关闭
"""
self.__is_shut_down.clear()
try:
# XXX: Consider using another file descriptor or connecting to the
# socket to wake this up instead of polling. Polling reduces our
# responsiveness to a shutdown request and wastes cpu at all other
# times.
with _ServerSelector() as selector:
selector.register(self, selectors.EVENT_READ)
while not self.__shutdown_request:
ready = selector.select(poll_interval)
if ready:
#如果 fd可用调用处理方法
self._handle_request_noblock()
self.service_actions()
finally:
self.__shutdown_request = False
self.__is_shut_down.set()
def _handle_request_noblock(self):
"""Handle one request, without blocking.
I assume that selector.select() has returned that the socket is
readable before this function was called, so there should be no risk of
blocking in get_request().
"""
try:
request, client_address = self.get_request()
except OSError:
return
if self.verify_request(request, client_address):
try:
#这里是真正处理请求的地方
self.process_request(request, client_address)
except Exception:
self.handle_error(request, client_address)
self.shutdown_request(request)
except:
self.shutdown_request(request)
raise
else:
self.shutdown_request(request)
def process_request(self, request, client_address):
"""Call finish_request.
Overridden by ForkingMixIn and ThreadingMixIn.
"""
self.finish_request(request, client_address)
self.shutdown_request(request)
#finish_request 最后调用这个BaseRequestHandler
class BaseRequestHandler:
'''
'''
def __init__(self, request, client_address, server):
self.request = request
self.client_address = client_address
self.server = server
self.setup()
try:
self.handle()
finally:
self.finish()
# C:\Users\Administrator\AppData\Local\Programs\Python\Python37\Lib\site-packages\django\core\servers\basehttp.py +156
def handle(self):
'''
这里对请求长度做限制
parse_request对http解包
'''
self.raw_requestline = self.rfile.readline(65537)
if len(self.raw_requestline) > 65536:
self.requestline = ''
self.request_version = ''
self.command = ''
self.send_error(414)
return
if not self.parse_request(): # An error code has been sent, just exit
return
handler = ServerHandler(
self.rfile, self.wfile, self.get_stderr(), self.get_environ()
)
handler.request_handler = self # backpointer for logging
handler.run(self.server.get_app())
#get_app 返回之前装配的WSGIAPP最终
class WSGIHandler(base.BaseHandler):
request_class = WSGIRequest
def __init__(self, *args, **kwargs):
super().__init__(*args, **kwargs)
self.load_middleware()
def __call__(self, environ, start_response):
set_script_prefix(get_script_name(environ))
signals.request_started.send(sender=self.__class__, environ=environ)
request = self.request_class(environ)
response = self.get_response(request)
response._handler_class = self.__class__
status = '%d %s' % (response.status_code, response.reason_phrase)
response_headers = [
*response.items(),
*(('Set-Cookie', c.output(header='')) for c in response.cookies.values()),
]
start_response(status, response_headers)
if getattr(response, 'file_to_stream', None) is not None and environ.get('wsgi.file_wrapper'):
response = environ['wsgi.file_wrapper'](response.file_to_stream)
return response
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