renderer: avoid redirect render requests

closes #11180

pkg/middleware/dashboard_redirect.go

@@ -6,6 +6,7 @@ import (
 
 	"github.com/grafana/grafana/pkg/bus"
 	m "github.com/grafana/grafana/pkg/models"
+	"github.com/grafana/grafana/pkg/setting"
 	"gopkg.in/macaron.v1"
 )
 
@@ -36,9 +37,14 @@ func RedirectFromLegacyDashboardUrl() macaron.Handler {
 func RedirectFromLegacyDashboardSoloUrl() macaron.Handler {
 	return func(c *m.ReqContext) {
 		slug := c.Params("slug")
+		renderRequest := c.QueryBool("render")
 
 		if slug != "" {
 			if url, err := getDashboardUrlBySlug(c.OrgId, slug); err == nil {
+				if renderRequest && strings.Contains(url, setting.AppSubUrl) {
+					url = strings.Replace(url, setting.AppSubUrl, "", 1)
+				}
+
 				url = strings.Replace(url, "/d/", "/d-solo/", 1)
 				url = fmt.Sprintf("%s?%s", url, c.Req.URL.RawQuery)
 				c.Redirect(url, 301)