http.StripPrefix 的參數含義

看下面兩行代碼：

http.Handle("/file/", http.StripPrefix("/file", http.FileServer(http.Dir("./output/"))))
http.Handle("/static/", http.StripPrefix("/static/", http.FileServer(http.Dir("./output/"))))
http.Handle("/file1", http.StripPrefix("/file1", http.FileServer(http.Dir("./output/"))))
http.Handle("/file2", http.StripPrefix("/file2/", http.FileServer(http.Dir("./output/"))))

注意看下圖結果：

• 一、2 行連接地址是帶對應前綴的。
• 3行連接地址不帶
• 4直接 404

 

 

 

TrimPrefix

TrimPrefix returns s without the provided leading prefix string. If s doesn't start with prefix, s is returned unchanged.

StripPrefix

// StripPrefix returns a handler that serves HTTP requests

// by removing the given prefix from the request URL's Path

// and invoking the handler h. StripPrefix handles a

// request for a path that doesn't begin with prefix by

// replying with an HTTP 404 not found error.

func StripPrefix(prefix string, h Handler) Handler {

    if prefix == "" {

        return h

    }

    return HandlerFunc(func(w ResponseWriter, r *Request) {

        if p := strings.TrimPrefix(r.URL.Path, prefix); len(p) < len(r.URL.Path) {

            r.URL.Path = p

            h.ServeHTTP(w, r)

        } else {

            NotFound(w, r)

        }

    })

}

如上圖代碼所示，

404 是觸發了上面的 else 條件。