fix: handle WeChat username conflicts (#771)

* handle username conflicts

* Update auth.go

Co-authored-by: roobtyan <roobtyan@qq.com>
Co-authored-by: Yang Luo <hsluoyz@qq.com>

controllers/auth.go

@@ -28,6 +28,7 @@ import (
 	"github.com/casdoor/casdoor/object"
 	"github.com/casdoor/casdoor/proxy"
 	"github.com/casdoor/casdoor/util"
+	"github.com/google/uuid"
 )
 
 func codeToResponse(code *object.Code) *Response {
@@ -252,7 +253,7 @@ func (c *ApiController) Login() {
 			record := object.NewRecord(c.Ctx)
 			record.Organization = application.Organization
 			record.User = user.Name
-			util.SafeGoroutine(func() {object.AddRecord(record)})
+			util.SafeGoroutine(func() { object.AddRecord(record) })
 		}
 	} else if form.Provider != "" {
 		application := object.GetApplication(fmt.Sprintf("admin/%s", form.Application))
@@ -345,7 +346,7 @@ func (c *ApiController) Login() {
 				record := object.NewRecord(c.Ctx)
 				record.Organization = application.Organization
 				record.User = user.Name
-				util.SafeGoroutine(func() {object.AddRecord(record)})
+				util.SafeGoroutine(func() { object.AddRecord(record) })
 			} else if provider.Category == "OAuth" {
 				// Sign up via OAuth
 				if !application.EnableSignUp {
@@ -358,6 +359,19 @@ func (c *ApiController) Login() {
 					return
 				}
 
+				// Handle username conflicts
+				tmpUser := object.GetUser(fmt.Sprintf("%s/%s", application.Organization, userInfo.Username))
+				if tmpUser != nil {
+					uid, err := uuid.NewRandom()
+					if err != nil {
+						c.ResponseError(err.Error())
+						return
+					}
+
+					uidStr := strings.Split(uid.String(), "-")
+					userInfo.Username = fmt.Sprintf("%s_%s", userInfo.Username, uidStr[1])
+				}
+
 				properties := map[string]string{}
 				properties["no"] = strconv.Itoa(len(object.GetUsers(application.Organization)) + 2)
 				user = &object.User{
@@ -394,7 +408,7 @@ func (c *ApiController) Login() {
 				record := object.NewRecord(c.Ctx)
 				record.Organization = application.Organization
 				record.User = user.Name
-				util.SafeGoroutine(func() {object.AddRecord(record)})
+				util.SafeGoroutine(func() { object.AddRecord(record) })
 			} else if provider.Category == "SAML" {
 				resp = &Response{Status: "error", Msg: "The account does not exist"}
 			}