の golang ドキュメントにアクセスするとhttp.Redirect
、実際には青色のヘッダーをクリックできます。
funcリダイレクト
自明のソース コード リストが表示されます。
// Redirect replies to the request with a redirect to url,
// which may be a path relative to the request path.
func Redirect(w ResponseWriter, r *Request, urlStr string, code int) {
if u, err := url.Parse(urlStr); err == nil {
// If url was relative, make absolute by
// combining with request path.
// The browser would probably do this for us,
// but doing it ourselves is more reliable.
// NOTE(rsc): RFC 2616 says that the Location
// line must be an absolute URI, like
// "http://www.google.com/redirect/",
// not a path like "/redirect/".
// Unfortunately, we don't know what to
// put in the host name section to get the
// client to connect to us again, so we can't
// know the right absolute URI to send back.
// Because of this problem, no one pays attention
// to the RFC; they all send back just a new path.
// So do we.
oldpath := r.URL.Path
if oldpath == "" { // should not happen, but avoid a crash if it does
oldpath = "/"
}
if u.Scheme == "" {
// no leading http://server
if urlStr == "" || urlStr[0] != '/' {
// make relative path absolute
olddir, _ := path.Split(oldpath)
urlStr = olddir + urlStr
}
var query string
if i := strings.Index(urlStr, "?"); i != -1 {
urlStr, query = urlStr[:i], urlStr[i:]
}
// clean up but preserve trailing slash
trailing := strings.HasSuffix(urlStr, "/")
urlStr = path.Clean(urlStr)
if trailing && !strings.HasSuffix(urlStr, "/") {
urlStr += "/"
}
urlStr += query
}
}
w.Header().Set("Location", urlStr)
w.WriteHeader(code)
// RFC2616 recommends that a short note "SHOULD" be included in the
// response because older user agents may not understand 301/307.
// Shouldn't send the response for POST or HEAD; that leaves GET.
if r.Method == "GET" {
note := "<a href=\"" + htmlEscape(urlStr) + "\">" + statusText[code] +
"</a>.\n"
fmt.Fprintln(w, note)
}
}
このトリックは、他の関数にも適用されます。