refactor: clean up code (#5308)

pkg/util/vhost/router.go

@@ -93,12 +93,19 @@ func (r *Routers) Del(domain, location, httpUser string) {
 	routersByHTTPUser[httpUser] = newVrs
 }
 
+// Get returns the best location match for an exact host and exact HTTP user.
+// It does not apply all-users, wildcard-domain, or catch-all-domain fallback.
 func (r *Routers) Get(host, path, httpUser string) (vr *Router, exist bool) {
 	host = strings.ToLower(host)
 
 	r.mutex.RLock()
 	defer r.mutex.RUnlock()
 
+	return r.getLocked(host, path, httpUser)
+}
+
+// getLocked performs an exact-host lookup; host must already be lower-cased.
+func (r *Routers) getLocked(host, path, httpUser string) (vr *Router, exist bool) {
 	routersByHTTPUser, found := r.indexByDomain[host]
 	if !found {
 		return
@@ -117,6 +124,49 @@ func (r *Routers) Get(host, path, httpUser string) (vr *Router, exist bool) {
 	return
 }
 
+func (r *Routers) getByRoute(host, path, httpUser string) (*Router, bool) {
+	host = strings.ToLower(host)
+
+	r.mutex.RLock()
+	defer r.mutex.RUnlock()
+
+	// First we check the full hostname; if it doesn't exist, then check wildcard domains.
+	// For example, test.example.com checks *.example.com before falling back to "*".
+	vr, ok := r.getExactOrAllUsersLocked(host, path, httpUser)
+	if ok {
+		return vr, true
+	}
+
+	hostSplit := strings.Split(host, ".")
+	// Keep two-label hosts out of the wildcard walk, so example.com does not match *.com.
+	for len(hostSplit) >= 3 {
+		// Replace the leftmost remaining label with the wildcard marker.
+		hostSplit[0] = "*"
+		host = strings.Join(hostSplit, ".")
+		vr, ok = r.getExactOrAllUsersLocked(host, path, httpUser)
+		if ok {
+			return vr, true
+		}
+		hostSplit = hostSplit[1:]
+	}
+
+	// Finally, try to check if there is one proxy whose domain is "*", which means match all domains.
+	return r.getExactOrAllUsersLocked("*", path, httpUser)
+}
+
+func (r *Routers) getExactOrAllUsersLocked(host, path, httpUser string) (*Router, bool) {
+	vr, ok := r.getLocked(host, path, httpUser)
+	if ok {
+		return vr, true
+	}
+	// Try to check if there is one proxy that doesn't specify routeByHTTPUser, it means match all.
+	vr, ok = r.getLocked(host, path, "")
+	if ok {
+		return vr, true
+	}
+	return nil, false
+}
+
 func (r *Routers) exist(host, path, httpUser string) (route *Router, exist bool) {
 	routersByHTTPUser, found := r.indexByDomain[host]
 	if !found {