9.6 HTTP Middleware

 PackageMainImport("IO"    "Log"    "Net/http")typeUserstringfunc(U User) toString ()string{return string(U)}typeAuthhandlerfunc(U User, w http.) Responsewriter, R *http. Request)funcMain () {//Secured APIMUX: = http. Newservemux () Mux. Handlefunc ("/api/users", Secure (func(W http. Responsewriter, R *http. Request) {io. WriteString (W,' [{' id ': ' 1 ', ' Login ': ' Ffghi '},{' id ': ' 2 ', ' Login ': ' FFGHJ '}] ')) Mux. Handlefunc ("/api/profile", Withuser (func(U User, w http.) Responsewriter, R *http. Request) {log. Println (u.tostring ()) Io. WriteString (W,"{\"User\":\""+u.tostring () +"\"}")}) http. Listenandserve (": 8080", MUX)}funcWithuser (H authhandler) http. Handlerfunc {return func(W http. Responsewriter, R *http. Request) {User: = R.header.get ("X-user")if Len(user) = =0{W.writeheader (http. statusunauthorized)return} h (User, W, r)}}funcSecure (H http. Handlerfunc) http. Handlerfunc {return func(W http. Responsewriter, R *http. Request) {sec: = R.header.get ("X-auth")ifSec! ="Authenticated"{W.writeheader (http. statusunauthorized)return} h (W, R)// Use the handler}}/*(sx3.5.3)? ~ Curl-x get-i http://127.0.0.1:8080/api/usershttp/1.1 401 UnauthorizedDate:mon, 2018 15:42:50 GMTcontent-length:0Content-type:text/plain; Charset=utf-8curl-x get-w "\nstatus:%{http_code}\n" Http://127.0.0.1:8080/api/usersstatus:401curl-x get-w "\nstatus:%{http_code}\n" Http://127.0.0.1:8080/api/users-H "x-auth:authenticated "[{"id": "1", "Login": "Ffghi"},{"id": "2", "Login": "Ffghj"}]status:200(sx3.5.3)? ~ Curl-x get-w "\nstatus:%{http_code}\n" Http://127.0.0.1:8080/api/profile-H "X-user:zrd "{"User": "Zrd"}status:200*/

在前面的例子中中间件的实现利用函数为一等公民的Golang特色。原handlerfunc包装成一个handlerfunc检查x-auth头。安全功能是用来保护handlerfunc，用于servemux的handlefunc方法。请注意，这只是一个简单的示例，但这种方式可以实现更复杂的解决方案。例如，用户的身份可以从标题标记和随后的提取，处理新类型可以定义为类AuthHandler func（U *用户，W http.responsewriter，R * HTTP请求）。功能的用户创建的servemux的handlerfunc。

9.6 HTTP Middleware