在回圈中向ServeMux宣告和分配處理程式不起作用-有解無憂

我有以下代碼，但它沒有按預期作業。具體來說，對任何端點的所有請求都作為對一個/banana/auth或多個/banana/description端點的請求進行處理。

type Route struct {
    AuthRoute        string
    DescriptionRoute string
}

var routes = [2]Route{
    {
        AuthRoute:        "/apple/auth",
        DescriptionRoute: "/apple/description",
    },
    {
        AuthRoute:        "/banana/auth",
        DescriptionRoute: "/banana/description",
    },
}

// ...
sm := http.NewServeMux()

for i, authServerConfig := range authServerConfigs {
    authHandler := http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
        authServerConfig.Auth(w, r)
    }
    sm.Handle(routes[i].AuthRoute, authHandler)

    descriptionHandler := http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
        authServerConfig.ServeDescription(w, r)
    }
    sm.Handle(routes[i].DescriptionRoute, descriptionHandler)
}

server := &http.Server{
    // ...
    Handler: sm,
    // ...
}
server.ListenAndServe()

當我繼續用這些陳述句替換 for 回圈時，它完全按照我的意愿作業：

    authHandlerApple := http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
        authServerConfig.Auth(w, r)
    }
    sm.Handle(routes[0].AuthRoute, authHandlerApple)

    descriptionHandlerApple := http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
        authServerConfig.ServeDescription(w, r)
    }
    sm.Handle(routes[0].DescriptionRoute, descriptionHandlerApple)

    authHandlerBanana := http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
        authServerConfig.Auth(w, r)
    }
    sm.Handle(routes[1].AuthRoute, authHandlerBanana)

    descriptionHandlerBanana := http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
        authServerConfig.ServeDescription(w, r)
    }
    sm.Handle(routes[1].DescriptionRoute, descriptionHandlerBanana)

問題是，我最初做錯了什么，如何避免撰寫第二個示例中的笨拙代碼？

uj5u.com熱心網友回復：

每個常見問題解答 - 作為 goroutines 運行的閉包會發生什么authServerConfig ，每個閉包在for回圈中共享該單個變數。要修復它，只需authServerConfig := authServerConfig在回圈中添加

for i, authServerConfig := range authServerConfigs {
     authServerConfig := authServerConfig

    authHandler := http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
        authServerConfig.Auth(w, r)
    })
    sm.Handle(routes[i].AuthRoute, authHandler)

    descriptionHandler := http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
        authServerConfig.ServeDescription(w, r)
    })
    sm.Handle(routes[i].DescriptionRoute, descriptionHandler)
}

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標籤：http去服务复用器

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