From db258585c8d062dd3165ab3f82be49dcdcce5d2e Mon Sep 17 00:00:00 2001
From: Evgeniy Scherbina <evgeniy.shcherbina.es@gmail.com>
Date: Tue, 31 Oct 2023 18:32:22 -0400
Subject: [PATCH] Improve get-cached-response method (#52)

---
 service/cachemdw/cache.go                | 6 ++++++
 service/cachemdw/errors.go               | 5 +++++
 service/cachemdw/is_cached_middleware.go | 2 +-
 3 files changed, 12 insertions(+), 1 deletion(-)
 create mode 100644 service/cachemdw/errors.go

diff --git a/service/cachemdw/cache.go b/service/cachemdw/cache.go
index 1f74dc2..a2202fa 100644
--- a/service/cachemdw/cache.go
+++ b/service/cachemdw/cache.go
@@ -90,6 +90,12 @@ func (c *ServiceCache) GetCachedQueryResponse(
 	ctx context.Context,
 	req *decode.EVMRPCRequestEnvelope,
 ) ([]byte, error) {
+	// if request isn't cacheable - there is no point to try to get it from cache so exit early with an error
+	cacheable := IsCacheable(c.ServiceLogger, req)
+	if !cacheable {
+		return nil, ErrRequestIsNotCacheable
+	}
+
 	key, err := GetQueryKey(c.cachePrefix, req)
 	if err != nil {
 		return nil, err
diff --git a/service/cachemdw/errors.go b/service/cachemdw/errors.go
new file mode 100644
index 0000000..225944c
--- /dev/null
+++ b/service/cachemdw/errors.go
@@ -0,0 +1,5 @@
+package cachemdw
+
+import "errors"
+
+var ErrRequestIsNotCacheable = errors.New("request is not cacheable")
diff --git a/service/cachemdw/is_cached_middleware.go b/service/cachemdw/is_cached_middleware.go
index 64a3b6c..483aa11 100644
--- a/service/cachemdw/is_cached_middleware.go
+++ b/service/cachemdw/is_cached_middleware.go
@@ -61,7 +61,7 @@ func (c *ServiceCache) IsCachedMiddleware(
 		// 1. if not cached or we encounter an error then mark as uncached and forward to next middleware
 		// 2. if cached then mark as cached, set cached response in context and forward to next middleware
 		cachedQueryResponse, err := c.GetCachedQueryResponse(r.Context(), decodedReq)
-		if err != nil && err != cache.ErrNotFound {
+		if err != nil && err != cache.ErrNotFound && err != ErrRequestIsNotCacheable {
 			// log unexpected error
 			c.Logger.Error().
 				Err(err).