Remove 03.4.md spaces
This commit is contained in:
vCaesar
150
zh/03.4.md
150
zh/03.4.md
@@ -9,11 +9,11 @@ Go的http有两个核心功能：Conn、ServeMux
|
||||
Go在等待客户端请求里面是这样写的：
|
||||
```Go
|
||||
|
||||
c, err := srv.newConn(rw)
|
||||
if err != nil {
|
||||
continue
|
||||
}
|
||||
go c.serve()
|
||||
c, err := srv.newConn(rw)
|
||||
if err != nil {
|
||||
continue
|
||||
}
|
||||
go c.serve()
|
||||
|
||||
```
|
||||
这里我们可以看到客户端的每次请求都会创建一个Conn，这个Conn里面保存了该次请求的信息，然后再传递到对应的handler，该handler中便可以读取到相应的header信息，这样保证了每个请求的独立性。
|
||||
@@ -24,85 +24,85 @@ Go在等待客户端请求里面是这样写的：
|
||||
它的结构如下：
|
||||
```Go
|
||||
|
||||
type ServeMux struct {
|
||||
mu sync.RWMutex //锁，由于请求涉及到并发处理，因此这里需要一个锁机制
|
||||
m map[string]muxEntry // 路由规则，一个string对应一个mux实体，这里的string就是注册的路由表达式
|
||||
hosts bool // 是否在任意的规则中带有host信息
|
||||
}
|
||||
type ServeMux struct {
|
||||
mu sync.RWMutex //锁，由于请求涉及到并发处理，因此这里需要一个锁机制
|
||||
m map[string]muxEntry // 路由规则，一个string对应一个mux实体，这里的string就是注册的路由表达式
|
||||
hosts bool // 是否在任意的规则中带有host信息
|
||||
}
|
||||
|
||||
```
|
||||
下面看一下muxEntry
|
||||
```Go
|
||||
|
||||
type muxEntry struct {
|
||||
explicit bool // 是否精确匹配
|
||||
h Handler // 这个路由表达式对应哪个handler
|
||||
pattern string //匹配字符串
|
||||
}
|
||||
type muxEntry struct {
|
||||
explicit bool // 是否精确匹配
|
||||
h Handler // 这个路由表达式对应哪个handler
|
||||
pattern string //匹配字符串
|
||||
}
|
||||
|
||||
```
|
||||
接着看一下Handler的定义
|
||||
```Go
|
||||
|
||||
type Handler interface {
|
||||
ServeHTTP(ResponseWriter, *Request) // 路由实现器
|
||||
}
|
||||
type Handler interface {
|
||||
ServeHTTP(ResponseWriter, *Request) // 路由实现器
|
||||
}
|
||||
|
||||
```
|
||||
Handler是一个接口，但是前一小节中的`sayhelloName`函数并没有实现ServeHTTP这个接口，为什么能添加呢？原来在http包里面还定义了一个类型`HandlerFunc`,我们定义的函数`sayhelloName`就是这个HandlerFunc调用之后的结果，这个类型默认就实现了ServeHTTP这个接口，即我们调用了HandlerFunc(f),强制类型转换f成为HandlerFunc类型，这样f就拥有了ServeHTTP方法。
|
||||
```Go
|
||||
|
||||
type HandlerFunc func(ResponseWriter, *Request)
|
||||
type HandlerFunc func(ResponseWriter, *Request)
|
||||
|
||||
// ServeHTTP calls f(w, r).
|
||||
func (f HandlerFunc) ServeHTTP(w ResponseWriter, r *Request) {
|
||||
f(w, r)
|
||||
}
|
||||
// ServeHTTP calls f(w, r).
|
||||
func (f HandlerFunc) ServeHTTP(w ResponseWriter, r *Request) {
|
||||
f(w, r)
|
||||
}
|
||||
```
|
||||
路由器里面存储好了相应的路由规则之后，那么具体的请求又是怎么分发的呢？请看下面的代码，默认的路由器实现了`ServeHTTP`：
|
||||
```Go
|
||||
|
||||
func (mux *ServeMux) ServeHTTP(w ResponseWriter, r *Request) {
|
||||
if r.RequestURI == "*" {
|
||||
w.Header().Set("Connection", "close")
|
||||
w.WriteHeader(StatusBadRequest)
|
||||
return
|
||||
}
|
||||
h, _ := mux.Handler(r)
|
||||
h.ServeHTTP(w, r)
|
||||
func (mux *ServeMux) ServeHTTP(w ResponseWriter, r *Request) {
|
||||
if r.RequestURI == "*" {
|
||||
w.Header().Set("Connection", "close")
|
||||
w.WriteHeader(StatusBadRequest)
|
||||
return
|
||||
}
|
||||
h, _ := mux.Handler(r)
|
||||
h.ServeHTTP(w, r)
|
||||
}
|
||||
```
|
||||
如上所示路由器接收到请求之后，如果是`*`那么关闭链接，不然调用`mux.Handler(r)`返回对应设置路由的处理Handler，然后执行`h.ServeHTTP(w, r)`
|
||||
|
||||
也就是调用对应路由的handler的ServerHTTP接口，那么mux.Handler(r)怎么处理的呢？
|
||||
```Go
|
||||
|
||||
func (mux *ServeMux) Handler(r *Request) (h Handler, pattern string) {
|
||||
if r.Method != "CONNECT" {
|
||||
if p := cleanPath(r.URL.Path); p != r.URL.Path {
|
||||
_, pattern = mux.handler(r.Host, p)
|
||||
return RedirectHandler(p, StatusMovedPermanently), pattern
|
||||
}
|
||||
}
|
||||
return mux.handler(r.Host, r.URL.Path)
|
||||
func (mux *ServeMux) Handler(r *Request) (h Handler, pattern string) {
|
||||
if r.Method != "CONNECT" {
|
||||
if p := cleanPath(r.URL.Path); p != r.URL.Path {
|
||||
_, pattern = mux.handler(r.Host, p)
|
||||
return RedirectHandler(p, StatusMovedPermanently), pattern
|
||||
}
|
||||
}
|
||||
return mux.handler(r.Host, r.URL.Path)
|
||||
}
|
||||
|
||||
func (mux *ServeMux) handler(host, path string) (h Handler, pattern string) {
|
||||
mux.mu.RLock()
|
||||
defer mux.mu.RUnlock()
|
||||
|
||||
// Host-specific pattern takes precedence over generic ones
|
||||
if mux.hosts {
|
||||
h, pattern = mux.match(host + path)
|
||||
}
|
||||
|
||||
func (mux *ServeMux) handler(host, path string) (h Handler, pattern string) {
|
||||
mux.mu.RLock()
|
||||
defer mux.mu.RUnlock()
|
||||
|
||||
// Host-specific pattern takes precedence over generic ones
|
||||
if mux.hosts {
|
||||
h, pattern = mux.match(host + path)
|
||||
}
|
||||
if h == nil {
|
||||
h, pattern = mux.match(path)
|
||||
}
|
||||
if h == nil {
|
||||
h, pattern = NotFoundHandler(), ""
|
||||
}
|
||||
return
|
||||
if h == nil {
|
||||
h, pattern = mux.match(path)
|
||||
}
|
||||
if h == nil {
|
||||
h, pattern = NotFoundHandler(), ""
|
||||
}
|
||||
return
|
||||
}
|
||||
```
|
||||
原来他是根据用户请求的URL和路由器里面存储的map去匹配的，当匹配到之后返回存储的handler，调用这个handler的ServeHTTP接口就可以执行到相应的函数了。
|
||||
|
||||
@@ -111,33 +111,33 @@ Handler是一个接口，但是前一小节中的`sayhelloName`函数并没有
|
||||
如下代码所示，我们自己实现了一个简易的路由器
|
||||
```Go
|
||||
|
||||
package main
|
||||
package main
|
||||
|
||||
import (
|
||||
"fmt"
|
||||
"net/http"
|
||||
)
|
||||
import (
|
||||
"fmt"
|
||||
"net/http"
|
||||
)
|
||||
|
||||
type MyMux struct {
|
||||
}
|
||||
type MyMux struct {
|
||||
}
|
||||
|
||||
func (p *MyMux) ServeHTTP(w http.ResponseWriter, r *http.Request) {
|
||||
if r.URL.Path == "/" {
|
||||
sayhelloName(w, r)
|
||||
return
|
||||
}
|
||||
http.NotFound(w, r)
|
||||
func (p *MyMux) ServeHTTP(w http.ResponseWriter, r *http.Request) {
|
||||
if r.URL.Path == "/" {
|
||||
sayhelloName(w, r)
|
||||
return
|
||||
}
|
||||
http.NotFound(w, r)
|
||||
return
|
||||
}
|
||||
|
||||
func sayhelloName(w http.ResponseWriter, r *http.Request) {
|
||||
fmt.Fprintf(w, "Hello myroute!")
|
||||
}
|
||||
func sayhelloName(w http.ResponseWriter, r *http.Request) {
|
||||
fmt.Fprintf(w, "Hello myroute!")
|
||||
}
|
||||
|
||||
func main() {
|
||||
mux := &MyMux{}
|
||||
http.ListenAndServe(":9090", mux)
|
||||
}
|
||||
func main() {
|
||||
mux := &MyMux{}
|
||||
http.ListenAndServe(":9090", mux)
|
||||
}
|
||||
```
|
||||
## Go代码的执行流程
|
||||
|
||||
|
||||
Reference in New Issue
Block a user