refactor: improve client initialization logic and ensure thread safety

common/utils/tphutil/tph.go

@@ -3,28 +3,37 @@ package tphutil
 import (
 	"encoding/json"
 	"strings"
+	"sync"
 
 	"github.com/krau/SaveAny-Bot/config"
 	"github.com/krau/SaveAny-Bot/pkg/telegraph"
 )
 
-var tphClient *telegraph.Client
+var (
+	tphClient *telegraph.Client
+	once      sync.Once
+)
 
 func DefaultClient() *telegraph.Client {
-	if tphClient != nil {
-		return tphClient
-	}
+	once.Do(func() {
+		tphClient = initDefault()
+	})
+	return tphClient
+}
+
+func initDefault() *telegraph.Client {
+	var client *telegraph.Client
 	if config.C().Telegram.Proxy.Enable && config.C().Telegram.Proxy.URL != "" {
 		proxyUrl := config.C().Telegram.Proxy.URL
 		var err error
-		tphClient, err = telegraph.NewClientWithProxy(proxyUrl)
+		client, err = telegraph.NewClientWithProxy(proxyUrl)
 		if err != nil {
-			tphClient = telegraph.NewClient()
+			client = telegraph.NewClient()
 		}
 	} else {
-		tphClient = telegraph.NewClient()
+		client = telegraph.NewClient()
 	}
-	return tphClient
+	return client
 }
 
 func GetNodeImages(node telegraph.Node) []string {