Question

假设我们有：

http.HandleFunc("/smth", smthPage)
http.HandleFunc("/", homePage)

用户在尝试错误的网址时会看到一个简单的“找不到404页面”。如何为该案例返回自定义页面？

有关gorilla / mux的更新

对于那些使用纯net / http包的人来说，接受的答案是可以接受的。

如果您使用gorilla / mux，您应该使用以下内容：

func main() {
    r := mux.NewRouter()
    r.NotFoundHandler = http.HandlerFunc(notFound)
}

并根据需要实施func notFound(w http.ResponseWriter, r *http.Request)。

Answer 1

我通常这样做：

package main

import (
    "fmt"
    "net/http"
)

func main() {
    http.HandleFunc("/", homeHandler)
    http.HandleFunc("/smth/", smthHandler)
    http.ListenAndServe(":12345", nil)
}

func homeHandler(w http.ResponseWriter, r *http.Request) {
    if r.URL.Path != "/" {
        errorHandler(w, r, http.StatusNotFound)
        return
    }
    fmt.Fprint(w, "welcome home")
}

func smthHandler(w http.ResponseWriter, r *http.Request) {
    if r.URL.Path != "/smth/" {
        errorHandler(w, r, http.StatusNotFound)
        return
    }
    fmt.Fprint(w, "welcome smth")
}

func errorHandler(w http.ResponseWriter, r *http.Request, status int) {
    w.WriteHeader(status)
    if status == http.StatusNotFound {
        fmt.Fprint(w, "custom 404")
    }
}

这里我简化了代码以仅显示自定义404，但实际上我使用此设置做了更多：我使用errorHandler处理所有HTTP错误，我在其中记录有用信息并向自己发送电子邮件。

Answer 2

以下是我选择的方法。它基于一个代码片段，因为我丢失了浏览器书签，所以我无法承认。

示例代码:(我把它放在我的主程序包中）

type hijack404 struct {
    http.ResponseWriter
    R *http.Request
    Handle404 func (w http.ResponseWriter, r *http.Request) bool
}

func (h *hijack404) WriteHeader(code int) {
    if 404 == code && h.Handle404(h.ResponseWriter, h.R) {
        panic(h)
    }

    h.ResponseWriter.WriteHeader(code)
}

func Handle404(handler http.Handler, handle404 func (w http.ResponseWriter, r *http.Request) bool) http.Handler {
    return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request){
        hijack := &hijack404{ ResponseWriter:w, R: r, Handle404: handle404 }

        defer func() {
            if p:=recover(); p!=nil {
                if p==hijack {
                    return
                }
                panic(p)
            }
        }()

        handler.ServeHTTP(hijack, r)
    })
}

func fire404(res http.ResponseWriter, req *http.Request) bool{
    fmt.Fprintf(res, "File not found. Please check to see if your URL is correct.");

    return true;
}

func main(){
    handler_statics := http.StripPrefix("/static/", http.FileServer(http.Dir("/Path_To_My_Static_Files")));

    var v_blessed_handler_statics http.Handler = Handle404(handler_statics, fire404);

    http.Handle("/static/", v_blessed_handler_statics);

    // add other handlers using http.Handle() as necessary

    if err := http.ListenAndServe(":8080", nil); err != nil{
        log.Fatal("ListenAndServe: ", err);
    }
}

请自定义func fire404以输出错误404的消息版本。

如果您正在使用Gorilla Mux，您可能希望用以下内容替换main函数：

func main(){
    handler_statics := http.StripPrefix("/static/", http.FileServer(http.Dir("/Path_To_My_Static_Files")));

    var v_blessed_handler_statics http.Handler = Handle404(handler_statics, fire404);

    r := mux.NewRouter();
    r.PathPrefix("/static/").Handler(v_blessed_handler_statics);

    // add other handlers with r.HandleFunc() if necessary...

    http.Handle("/", r);

    log.Fatal(http.ListenAndServe(":8080", nil));
}

如果错误，请将代码更正，因为我只是Go的新手。感谢。

Answer 3

您只需创建自己的notFound处理程序并使用HandleFunc将其注册为您未处理的路径。

如果您希望最大限度地控制路由逻辑，则需要使用自己的自定义服务器和自定义处理程序类型。

这允许您实现比HandleFunc允许的更复杂的路由逻辑。

Answer 4

我认为干净的方法是这样的：

func main() {

http.HandleFunc("/calculator", calculatorHandler)
http.HandleFunc("/history", historyHandler)
http.HandleFunc("/", notFoundHandler)

log.Fatal(http.ListenAndServe(":80", nil))
}

如果地址不是/calulator或/history，则处理notFoundHandler函数。

Answer 5

古老的线索，但我刚刚制作了拦截http.ResponseWriter的东西，可能与此相关。

package main

//GAE POC originally inspired by https://thornelabs.net/2017/03/08/use-google-app-engine-and-golang-to-host-a-static-website-with-same-domain-redirects.html

import (
    "net/http"
)

func init() {
    http.HandleFunc("/", handler)
}

// HeaderWriter is a wrapper around http.ResponseWriter which manipulates headers/content based on upstream response
type HeaderWriter struct {
    original http.ResponseWriter
    done     bool
}

func (hw *HeaderWriter) Header() http.Header {
    return hw.original.Header()
}

func (hw *HeaderWriter) Write(b []byte) (int, error) {
    if hw.done {
        //Silently let caller think they are succeeding in sending their boring 404...
        return len(b), nil
    }
    return hw.original.Write(b)
}

func (hw *HeaderWriter) WriteHeader(s int) {
    if hw.done {
        //Hmm... I don't think this is needed...
        return
    }
    if s < 400 {
        //Set CC header when status is < 400...
        //TODO: Use diff header if static extensions
        hw.original.Header().Set("Cache-Control", "max-age=60, s-maxage=2592000, public")
    }
    hw.original.WriteHeader(s)
    if s == 404 {
        hw.done = true
        hw.original.Write([]byte("This be custom 404..."))
    }
}

func handler(w http.ResponseWriter, r *http.Request) {
    urls := map[string]string{
        "/example-post-1.html": "https://example.com/post/example-post-1.html",
        "/example-post-2.html": "https://example.com/post/example-post-2.html",
        "/example-post-3.html": "https://example.com/post/example-post-3.html",
    }
    w.Header().Set("Strict-Transport-Security", "max-age=15768000")
    //TODO: Put own logic
    if value, ok := urls[r.URL.Path]; ok {
        http.Redirect(&HeaderWriter{original: w}, r, value, 301)
    } else {
        http.ServeFile(&HeaderWriter{original: w}, r, "static/"+r.URL.Path)
    }
}

Answer 6

也许我错了，但我刚检查过来源：http://golang.org/src/pkg/net/http/server.go

似乎很难指定自定义NotFound（）函数：NotFoundHandler（）返回一个名为NotFound（）的硬编码函数。

可能你应该提交一个问题。

作为一种解决方法，您可以使用“/”处理程序，如果没有找到其他处理程序，这是一个后备（因为它是最短的处理程序）。因此，检查该处理程序中是否存在页面并返回自定义404错误。

Answer 7

您可以定义

http.HandleFunc("/", func(writer http.ResponseWriter, request *http.Request) {
    if request.URL.Path != "/" {
        writer.WriteHeader(404)
        writer.Write([]byte(`not found, da xiong dei !!!`))
        return
    }
})

当找不到访问资源时，它将执行到http.HandleFunc（“ /”，xxx）

显示带有标准http包的自定义404错误页面

7 个答案: