如何在Golang中使用正则表达式获取url模式？

Question

How to use regular expression matching URL, which does decide to use the corresponding function processing

package main

import(
  "fmt"
  "net/http"
)

func main() {
  http.HandleFunc("/pattern", resolve)
  http.ListenAndServe(":8080", nil)
}

func resolve(w http.ResponseWriter, r * http.Request) {
  fmt.Println(r.URL.Host)
}

Answer 1

http.HandleFunc() can not be used to register a pattern to match a regular expression. In short, the pattern specified at HandleFunc() can match a fixed, rooted path (like /favico.ico) or rooted subtrees (like /images/), longer patterns take precedence over shorter ones. You can find more details at the doc of the ServeMux type.

What you can do is register your handler to a rooted subtree which may be everything with the / pattern, and inside your handler you can do further regexp matching and routing.

For example:

func main() {
    http.HandleFunc("/", route) // Match everything
    http.ListenAndServe(":8080", nil)
}

var rNum = regexp.MustCompile(`\d`)  // Has digit(s)
var rAbc = regexp.MustCompile(`abc`) // Contains "abc"

func route(w http.ResponseWriter, r *http.Request) {
    switch {
    case rNum.MatchString(r.URL.Path):
        digits(w, r)
    case rAbc.MatchString(r.URL.Path):
        abc(w, r)
    default:
        w.Write([]byte("Unknown Pattern"))
    }
}

func digits(w http.ResponseWriter, r *http.Request) {
    w.Write([]byte("Has digits"))
}

func abc(w http.ResponseWriter, r *http.Request) {
    w.Write([]byte("Has abc"))
}

Or use an external library like Gorilla MUX.