Refactor URL detection (#29960)

"Redirect" functions should only redirect if the target is for current Gitea site.

services/context/context_response.go

@@ -44,14 +44,14 @@ func RedirectToUser(ctx *Base, userName string, redirectUserID int64) {
 	ctx.Redirect(path.Join(setting.AppSubURL, redirectPath), http.StatusTemporaryRedirect)
 }
 
-// RedirectToFirst redirects to first not empty URL
-func (ctx *Context) RedirectToFirst(location ...string) {
+// RedirectToCurrentSite redirects to first not empty URL which belongs to current site
+func (ctx *Context) RedirectToCurrentSite(location ...string) {
 	for _, loc := range location {
 		if len(loc) == 0 {
 			continue
 		}
 
-		if httplib.IsRiskyRedirectURL(loc) {
+		if !httplib.IsCurrentGiteaSiteURL(loc) {
 			continue
 		}