Backend Plugins: Support handling of streaming resource response (#22580)

Use v0.19.0 of SDK.
Support handling of streaming resource response.
Disable gzip/compression middleware for resources 
to allow chunked/streaming response to clients the gzip
middleware had to be disabled since it buffers the full
response before sending it to the client.

Closes #22569

Co-Authored-By: Arve Knudsen <arve.knudsen@gmail.com>

pkg/middleware/util.go

@@ -8,6 +8,8 @@ import (
 	"gopkg.in/macaron.v1"
 )
 
+const resourcesPath = "/resources"
+
 func Gziper() macaron.Handler {
 	gziperLogger := log.New("gziper")
 	gziper := gzip.Gziper()
@@ -27,6 +29,11 @@ func Gziper() macaron.Handler {
 			return
 		}
 
+		// ignore resources
+		if (strings.HasPrefix(requestPath, "/api/datasources/") || strings.HasPrefix(requestPath, "/api/plugins/")) && strings.Contains(requestPath, resourcesPath) {
+			return
+		}
+
 		if _, err := ctx.Invoke(gziper); err != nil {
 			gziperLogger.Error("Invoking gzip handler failed", "err", err)
 		}