我可以想到几种方法来做到这一点。
传递上下文
首先，您可以更改签名以接受上下文
type appHandler func(http.ResponseWriter, *http.Request, context.Context) *appErrorfunc (fn appHandler) ServeHTTP(w http.ResponseWriter, r *http.Request) { if e := fn(w, r, nil); e != nil { // e is *appError, not os.Error. http.Error(w, e.Message, e.Code) }}现在，我假设AuthHandler与身份验证有关，并在上下文对象中设置了用户。
您可以做的是创建另一个设置上下文的类型处理程序。像这样
type authHandler func(http.ResponseWriter, *http.Request, context.Context) *appErrorfunc (fn authHandler) ServeHTTP(w http.ResponseWriter, r *http.Request) { // setup authentication here uid := 1 // setup the context the way you want parent := context.TODO() ctx := context.WithValue(parent, userIdKey, uid) if e := fn(w, r, ctx); e != nil { // e is *appError, not os.Error.http.Error(w, e.Message, e.Code) } }这样您可以通过以下方式使用它
func init() {http.Handle("/view", appHandler(viewRecord)) // don't require authentication http.Handle("/viewAuth", authHandler(viewRecord)) // require authentication }这是完整的代码
package mainimport ( "fmt" "net/http" "pre.google.com/p/go.net/context")type appError struct { Error error Message string Code int}type key intconst userIdKey key = 0type appHandler func(http.ResponseWriter, *http.Request, context.Context) *appErrorfunc (fn appHandler) ServeHTTP(w http.ResponseWriter, r *http.Request) { if e := fn(w, r, nil); e != nil { // e is *appError, not os.Error. http.Error(w, e.Message, e.Code) }}type authHandler func(http.ResponseWriter, *http.Request, context.Context) *appErrorfunc (fn authHandler) ServeHTTP(w http.ResponseWriter, r *http.Request) { // setup authentication here uid := 1 // setup the context the way you want parent := context.TODO() ctx := context.WithValue(parent, userIdKey, uid) if e := fn(w, r, ctx); e != nil { // e is *appError, not os.Error. http.Error(w, e.Message, e.Code) }}func viewRecord(w http.ResponseWriter, r *http.Request, c context.Context) *appError { if c == nil { fmt.Fprintf(w, "User are not logged in") } else { uid := c.Value(userIdKey) fmt.Fprintf(w, "User logged in with uid: %d", uid) } return nil}func init() { http.Handle("/view", appHandler(viewRecord)) // viewRecord is an appHandler function http.Handle("/viewAuth", authHandler(viewRecord)) // viewRecord is an authHandler function}func main() { http.ListenAndServe(":8080", nil)}创建地图上下文
您无需传递上下文，而是创建
var contexts map[*http.Request]context.Context
并获得上下文中
view使用
contexts[r]。
但是由于映射不是线程安全的，因此必须使用互斥锁保护对映射的访问。
猜猜是什么，这就是大猩猩上下文正在为您做的事情，我认为这是更好的方法
https://github.com/gorilla/context/blob/master/context.go#l20-28
这是完整的代码
package mainimport ( "fmt" "net/http" "github.com/gorilla/context")type appError struct { Error error Message string Code int}type key intconst userIdKey key = 0type appHandler func(http.ResponseWriter, *http.Request) *appErrorfunc (fn appHandler) ServeHTTP(w http.ResponseWriter, r *http.Request) { if e := fn(w, r); e != nil { // e is *appError, not os.Error. http.Error(w, e.Message, e.Code) }}type authHandler func(http.ResponseWriter, *http.Request) *appErrorfunc (fn authHandler) ServeHTTP(w http.ResponseWriter, r *http.Request) { // setup authentication here uid := 1 context.Set(r, userIdKey, uid) if e := fn(w, r); e != nil { // e is *appError, not os.Error. http.Error(w, e.Message, e.Code) }}func viewRecord(w http.ResponseWriter, r *http.Request) *appError { if uid, ok := context.GetOk(r, userIdKey); !ok { fmt.Fprintf(w, "User are not logged in") } else { fmt.Fprintf(w, "User logged in with uid: %d", uid) } return nil}func init() { http.Handle("/view", appHandler(viewRecord)) // don't require authentication http.Handle("/viewAuth", authHandler(viewRecord)) // require authentication}func main() { http.ListenAndServe(":8080", nil)}您还可以选择包装函数而不是类型函数进行身份验证
func AuthHandler(h appHandler) appHandler { return func(w http.ResponseWriter, r *http.Request) *appError { // setup authentication here uid := 1 context.Set(r, userIdKey, uid) return h(w, r) } }func init() {http.Handle("/view", appHandler(viewRecord)) // don't require authentication http.Handle("/viewAuth", appHandler(AuthHandler(viewRecord))) // require authentication }
