AuthN: add utility functions for different type of login responses (#64133)

* AuthN: add utility functions to handle response and redirect after
successful login

* API: Reuse utility functions for logins if authnService flag is enabled

pkg/api/login.go

@@ -208,22 +208,8 @@ func (hs *HTTPServer) LoginPost(c *contextmodel.ReqContext) response.Response {
 			return response.Err(err)
 		}
 
-		cookies.WriteSessionCookie(c, hs.Cfg, identity.SessionToken.UnhashedToken, hs.Cfg.LoginMaxLifetime)
-		result := map[string]interface{}{
-			"message": "Logged in",
-		}
-
-		if redirectTo := c.GetCookie("redirect_to"); len(redirectTo) > 0 {
-			if err := hs.ValidateRedirectTo(redirectTo); err == nil {
-				result["redirectUrl"] = redirectTo
-			} else {
-				c.Logger.Info("Ignored invalid redirect_to cookie value.", "url", redirectTo)
-			}
-			cookies.DeleteCookie(c.Resp, "redirect_to", hs.CookieOptionsFromCfg)
-		}
-
 		metrics.MApiLoginPost.Inc()
-		return response.JSON(http.StatusOK, result)
+		return authn.HandleLoginResponse(c.Req, c.Resp, hs.Cfg, identity, hs.ValidateRedirectTo)
 	}
 
 	cmd := dtos.LoginCommand{}

pkg/api/login_oauth.go

@@ -114,15 +114,7 @@ func (hs *HTTPServer) OAuthLogin(ctx *contextmodel.ReqContext) {
 		}
 
 		metrics.MApiLoginOAuth.Inc()
-		cookies.WriteSessionCookie(ctx, hs.Cfg, identity.SessionToken.UnhashedToken, hs.Cfg.LoginMaxLifetime)
-
-		redirectURL := setting.AppSubUrl + "/"
-		if redirectTo := ctx.GetCookie("redirect_to"); len(redirectTo) > 0 && hs.ValidateRedirectTo(redirectTo) == nil {
-			redirectURL = redirectTo
-			cookies.DeleteCookie(ctx.Resp, "redirect_to", hs.CookieOptionsFromCfg)
-		}
-
-		ctx.Redirect(redirectURL)
+		authn.HandleLoginRedirect(ctx.Req, ctx.Resp, hs.Cfg, identity, hs.ValidateRedirectTo)
 		return
 	}