go - 如何检测是否调用了重定向

Question

我有以下代码

package main

import (
    "log"
    "net/http"
)

func fooHandler(w http.ResponseWriter, r *http.Request) {
    // Here an if condition, if should redirect or not
    http.Redirect(w, r, "http://www.google.com", 301)
    // Do something....
    // Call function if redirect was invoked

}

func main() {
    http.HandleFunc("/", fooHandler)
    err := http.ListenAndServe(":9090", nil)
    if err != nil {
        log.Fatal("ListenAndServe: ", err)
    }
}

如何检测响应对象中是否写入了重定向？

Answer 1

您可以检查响应的状态(针对 3xx redirection status code )，如 http REST driver 中所示:

    req, err = http.NewRequest(verb, url, body)

    if err != nil {
        return nil, err
    }

    for k, v := range headers {
        req.Header.Add(k, v)
    }

    resp, err = d.httpClient.Do(req)

    if err != nil {
        return nil, err
    }

    log.Printf("Exec responce: %v\n", resp)

    statusCode := resp.StatusCode


    if statusCode == 307 { // Temporary Redirect

        // For instance (put your own code here)

        redirectUrl, ok := resp.Header["Location"]
        if !ok {
            return nil, fmt.Errorf("%s %s", "Failed to redirect:", "header key 'Location' wasn't found")
        }
        log.Printf("Redirecting: '%s' --> '%s'", url, redirectUrl[0])
        url = redirectUrl[0]
        continue

    }