add option to block domains, add option to resolve specific domains through specific proxies, option to set the check interval

config.example.yml

@@ -4,6 +4,9 @@ http_port:                 9000
 # How many proxies will be checked at once?
 proxy_checkers:            50
 
+# The interval between proxy checks in seconds.
+proxy_check_interval:      60
+
 # URL to get a proxy's IP.
 ip_checker_url:            https://api.ipify.org
 
@@ -32,3 +35,12 @@ thirdparty_bypass_domains:
 # Shuffle the proxy lists whenever the background thread refreshes them.
 # If false, round-robin on default order.
 shuffle_proxies:           false
+
+# Don't allow requests to these domains through the proxy.
+blocked_domains:
+  - example.com
+
+# Resolve specific domains through specific proxies.
+# Proxies here are not validated.
+resolve_through:
+  github.com:              http://1.2.3.4:3128

src/config/config.go

@@ -19,6 +19,9 @@ type Config struct {
 	ThirdpartyTestUrls      []string
 	ThirdpartyBypassDomains []string
 	ShuffleProxies          bool
+	BlockedDomains          []string
+	ResolveThrough          map[string]string
+	ProxyCheckInterval      int
 }
 
 func SetConfig(configFile string) (*Config, error) {
@@ -36,6 +39,9 @@ func SetConfig(configFile string) (*Config, error) {
 	viper.SetDefault("thirdparty_test_urls", make([]string, 0))
 	viper.SetDefault("thirdparty_bypass_domains", make([]string, 0))
 	viper.SetDefault("shuffle_proxies", false)
+	viper.SetDefault("blocked_domains", make([]string, 0))
+	viper.SetDefault("resolve_through", make(map[string]string))
+	viper.SetDefault("proxy_check_interval", 60)
 
 	err := viper.ReadInConfig()
 	if err != nil {
@@ -51,6 +57,9 @@ func SetConfig(configFile string) (*Config, error) {
 		ThirdpartyTestUrls:      viper.GetStringSlice("thirdparty_test_urls"),
 		ThirdpartyBypassDomains: viper.GetStringSlice("thirdparty_bypass_domains"),
 		ShuffleProxies:          viper.GetBool("shuffle_proxies"),
+		BlockedDomains:          viper.GetStringSlice("blocked_domains"),
+		ResolveThrough:          viper.GetStringMapString("resolve_through"),
+		ProxyCheckInterval:      viper.GetInt("proxy_check_interval"),
 	}
 
 	if len(config.ProxyPoolOurs) == 0 && len(config.ProxyPoolThirdparty) == 0 {

src/proxy-loadbalancer.go

@@ -82,6 +82,8 @@ func main() {
 		log.Fatalf(`Failed to load config: %s`, err)
 	}
 
+	log.Debugf(`Proxy check interval: %d sec`, config.GetConfig().ProxyCheckInterval)
+
 	proxyCluster := proxy.NewForwardProxyCluster()
 	go func() {
 		log.Fatal(http.ListenAndServe(":"+configData.HTTPPort, proxyCluster))

src/proxy/handleConnect.go

@@ -24,6 +24,7 @@ func logProxyRequest(remoteAddr string, proxyHost string, targetHost string, ret
 }
 
 func (p *ForwardProxyCluster) validateRequestAndGetProxy(w http.ResponseWriter, req *http.Request) (string, string, string, string, *url.URL, error) {
+	urlHostname := req.URL.Hostname()
 	if p.BalancerReady.GetCount() != 0 {
 		errStr := "proxy is not ready"
 		http.Error(w, errStr, http.StatusServiceUnavailable)
@@ -39,6 +40,12 @@ func (p *ForwardProxyCluster) validateRequestAndGetProxy(w http.ResponseWriter,
 		return "", "", "", "", nil, errors.New(errStr)
 	}
 
+	if slices.Contains(config.GetConfig().BlockedDomains, urlHostname) {
+		errStr := "this domain has been blocked"
+		http.Error(w, errStr, http.StatusUnavailableForLegalReasons)
+		return "", "", "", "", nil, errors.New(errStr)
+	}
+
 	headerIncludeBrokenThirdparty := req.Header.Get(HeaderThirdpartyIncludeBroken)
 	req.Header.Del(HeaderThirdpartyIncludeBroken)
 	headerBypassThirdparty := req.Header.Get(HeaderThirdpartyBypass)
@@ -50,15 +57,20 @@ func (p *ForwardProxyCluster) validateRequestAndGetProxy(w http.ResponseWriter,
 	}
 
 	var selectedProxy string
-	if slices.Contains(config.GetConfig().ThirdpartyBypassDomains, req.URL.Hostname()) {
-		selectedProxy = p.getProxyFromOurs()
+
+	if val, ok := config.GetConfig().ResolveThrough[urlHostname]; ok {
+		selectedProxy = val
 	} else {
-		if headerIncludeBrokenThirdparty != "" {
-			selectedProxy = p.getProxyFromAllWithBroken()
-		} else if headerBypassThirdparty != "" {
+		if slices.Contains(config.GetConfig().ThirdpartyBypassDomains, urlHostname) {
 			selectedProxy = p.getProxyFromOurs()
 		} else {
-			selectedProxy = p.getProxyFromAll()
+			if headerIncludeBrokenThirdparty != "" {
+				selectedProxy = p.getProxyFromAllWithBroken()
+			} else if headerBypassThirdparty != "" {
+				selectedProxy = p.getProxyFromOurs()
+			} else {
+				selectedProxy = p.getProxyFromAll()
+			}
 		}
 	}
 	if selectedProxy == "" {
@@ -82,7 +94,10 @@ func (p *ForwardProxyCluster) proxyHttpConnect(w http.ResponseWriter, req *http.
 	_, proxyUser, proxyPass, proxyHost, parsedProxyUrl, err := p.validateRequestAndGetProxy(w, req)
 	if err != nil {
 		// Error has already been handled, just log and return.
-		log.Debugf(`%s -> %s -- HTTP -- Rejecting request: %s`, remoteAddr, proxyHost, err)
+		if proxyHost == "" {
+			proxyHost = "none"
+		}
+		log.Debugf(`%s -> %s -> %s -- HTTP -- Rejecting request: %s`, remoteAddr, proxyHost, req.Host, err)
 		return
 	}
 	var returnCode *int
@@ -132,7 +147,10 @@ func (p *ForwardProxyCluster) proxyHttpsConnect(w http.ResponseWriter, req *http
 	_, proxyUser, proxyPass, proxyHost, _, err := p.validateRequestAndGetProxy(w, req)
 	if err != nil {
 		// Error has already been handled, just log and return.
-		log.Debugf(`%s -> %s -- CONNECT -- Rejecting request: %s`, remoteAddr, proxyHost, err)
+		if proxyHost == "" {
+			proxyHost = "none"
+		}
+		log.Debugf(`%s -> %s -> %s -- CONNECT -- Rejecting request: %s`, remoteAddr, proxyHost, targetHost, err)
 		return
 	}
 	var returnCode *int

src/proxy/threads.go

@@ -127,7 +127,7 @@ func (p *ForwardProxyCluster) ValidateProxiesThread() {
 		p.mu.RUnlock()
 
 		p.refreshInProgress = false
-		time.Sleep(60 * time.Second)
+		time.Sleep(time.Duration(config.GetConfig().ProxyCheckInterval) * time.Second)
 	}
 }