DataSourceProxy: Handle URL parsing error (#23731)

* pluginproxy: Handle URL parsing error
* pkg/api: Validate data source URLs
* pkg/api: Return 400 for URL validation error

pkg/api/dataproxy.go

@@ -1,6 +1,9 @@
 package api
 
 import (
+	"errors"
+	"fmt"
+
 	"github.com/grafana/grafana/pkg/api/pluginproxy"
 	"github.com/grafana/grafana/pkg/infra/metrics"
 	"github.com/grafana/grafana/pkg/models"
@@ -32,7 +35,15 @@ func (hs *HTTPServer) ProxyDataSourceRequest(c *models.ReqContext) {
 	// macaron does not include trailing slashes when resolving a wildcard path
 	proxyPath := ensureProxyPathTrailingSlash(c.Req.URL.Path, c.Params("*"))
 
-	proxy := pluginproxy.NewDataSourceProxy(ds, plugin, c, proxyPath, hs.Cfg)
+	proxy, err := pluginproxy.NewDataSourceProxy(ds, plugin, c, proxyPath, hs.Cfg)
+	if err != nil {
+		if errors.Is(err, pluginproxy.URLValidationError{}) {
+			c.JsonApiErr(400, fmt.Sprintf("Invalid data source URL: %q", ds.Url), err)
+		} else {
+			c.JsonApiErr(500, "Failed creating data source proxy", err)
+		}
+		return
+	}
 	proxy.HandleRequest()
 }