feat: add ability to whitelist specific query names when adding graph…

…ql middleware (#29)

* feat: add ability to whitelist specific query names when adding graphql middleware

* chore: add docs for whitelisting

README.md

@@ -164,7 +164,11 @@ For GraphQL endpoints it is possible to provide a list of atoms that will be pas
 field :user, :user do
   arg :id, non_null(:id)
 
-  middleware RequestCache.Middleware, ttl: :timer.seconds(60), cache: MyCacheModule, labels: [:service, :endpoint]
+  middleware RequestCache.Middleware,
+    ttl: :timer.seconds(60),
+    cache: MyCacheModule,
+    labels: [:service, :endpoint],
+    whitelisted_query_names: ["MyQueryName"] # By default all queries are cached, can also whitelist based off query name from GQL Document
 
   resolve &Resolvers.User.find/2
 end

lib/request_cache/middleware.ex

@@ -18,18 +18,33 @@ if absinthe_loaded? do
       enable_cache_for_resolution(resolution, ttl: ttl)
     end
 
-    defp enable_cache_for_resolution(resolution, opts) do
+    defp ensure_valid_ttl(opts) do
+      ttl = opts[:ttl] || RequestCache.Config.default_ttl()
+
+      Keyword.put(opts, :ttl, ttl)
+    end
+
+    defp enable_cache_for_resolution(%Absinthe.Resolution{} = resolution, opts) do
       resolution = resolve_resolver_func_middleware(resolution, opts)
 
       if resolution.context[RequestCache.Config.conn_private_key()][:enabled?] do
         Util.verbose_log("[RequestCache.Middleware] Enabling cache for resolution")
 
+        root_resolution_path_item = List.last(resolution.path)
+
+        cache_request? = !!root_resolution_path_item &&
+                         root_resolution_path_item.schema_node.name === "RootQueryType" &&
+                         query_name_whitelisted?(root_resolution_path_item.name, opts)
+
         %{resolution |
           value: resolution.value || opts[:value],
           context: Map.update!(
             resolution.context,
             RequestCache.Config.conn_private_key(),
-            &Util.deep_merge(&1, request: opts, cache_request?: true)
+            &Util.deep_merge(&1,
+              request: opts,
+              cache_request?: cache_request?
+            )
           )
         }
       else
@@ -49,10 +64,8 @@ if absinthe_loaded? do
 
     defp resolver_middleware?(opts), do: opts[:value]
 
-    defp ensure_valid_ttl(opts) do
-      ttl = opts[:ttl] || RequestCache.Config.default_ttl()
-
-      Keyword.put(opts, :ttl, ttl)
+    defp query_name_whitelisted?(query_name, opts) do
+      is_nil(opts[:whitelisted_query_names]) or query_name in opts[:whitelisted_query_names]
     end
 
     @spec store_result(

lib/request_cache/plug.ex

@@ -34,13 +34,20 @@ defmodule RequestCache.Plug do
     end
   end
 
-  defp call_for_api_type(%Plug.Conn{request_path: path, method: "GET", query_string: query_string} = conn, opts) when path in @graphql_paths do
+  defp call_for_api_type(%Plug.Conn{
+    request_path: path,
+    method: "GET",
+    query_string: query_string
+  } = conn, opts) when path in @graphql_paths do
     Util.verbose_log("[RequestCache.Plug] GraphQL query detected")
 
     maybe_return_cached_result(conn, opts, path, query_string)
   end
 
-  defp call_for_api_type(%Plug.Conn{request_path: path, method: "GET"} = conn, opts) when path not in @graphql_paths do
+  defp call_for_api_type(%Plug.Conn{
+    request_path: path,
+    method: "GET"
+  } = conn, opts) when path not in @graphql_paths do
     Util.verbose_log("[RequestCache.Plug] REST path detected")
 
     cache_key = rest_cache_key(conn)

test/request_cache_absinthe_test.exs

@@ -8,6 +8,14 @@ defmodule RequestCacheAbsintheTest do
   defmodule Schema do
     use Absinthe.Schema
 
+    object :nested_item do
+      field :world, :string
+    end
+
+    object :item do
+      field :tester, :nested_item
+    end
+
     query do
       field :hello, :string do
         resolve fn _, %{context: %{call_pid: pid}} ->
@@ -69,6 +77,18 @@ defmodule RequestCacheAbsintheTest do
           {:error, %{code: :not_found, message: "TesT"}}
         end
       end
+
+      field :whitelist_cached_hello, :item do
+        middleware RequestCache.Middleware, whitelisted_query_names: ["SmallHello"]
+
+        resolve fn _, _ ->
+          {:ok, %{
+            tester: %{
+              world: "hello"
+            }
+          }}
+        end
+      end
     end
   end
 
@@ -108,6 +128,9 @@ defmodule RequestCacheAbsintheTest do
   @uncached_error_query "query UncachedFound { uncachedError }"
   @cached_all_error_query "query CachedAllFound { cachedAllError(code: \"not_found\") }"
   @cached_not_found_error_query "query CachedNotFound { cachedNotFoundError }"
+  @whitelist_named_query "query SmallHello { whitelistCachedHello { tester { world }} }"
+  @whitelist_uncached_named_query "query SmallerHello { whitelistCachedHello { tester { world }} }"
+  @whitelist_unnamed_query "query { whitelistCachedHello { tester { world }} }"
 
   setup do
     {:ok, pid} = EnsureCalledOnlyOnce.start_link()
@@ -245,6 +268,48 @@ defmodule RequestCacheAbsintheTest do
     end) =~ "RequestCache requested"
   end
 
+  @tag capture_log: true
+  test "whitelist doesn't cache unspecified queries" do
+    assert [] = :get
+      |> conn(graphql_url(@whitelist_uncached_named_query))
+      |> RequestCache.Support.Utils.ensure_default_opts(request: [whitelisted_query_names: ["SmallHello"]])
+      |> Router.call([])
+      |> get_resp_header(RequestCache.Plug.request_cache_header())
+
+    assert [] = :get
+      |> conn(graphql_url(@whitelist_uncached_named_query))
+      |> RequestCache.Support.Utils.ensure_default_opts(request: [whitelisted_query_names: ["SmallHello"]])
+      |> Router.call([])
+      |> get_resp_header(RequestCache.Plug.request_cache_header())
+
+    assert [] = :get
+      |> conn(graphql_url(@whitelist_unnamed_query))
+      |> RequestCache.Support.Utils.ensure_default_opts(request: [whitelisted_query_names: ["SmallHello"]])
+      |> Router.call([])
+      |> get_resp_header(RequestCache.Plug.request_cache_header())
+
+    assert [] = :get
+      |> conn(graphql_url(@whitelist_unnamed_query))
+      |> RequestCache.Support.Utils.ensure_default_opts(request: [whitelisted_query_names: ["SmallHello"]])
+      |> Router.call([])
+      |> get_resp_header(RequestCache.Plug.request_cache_header())
+  end
+
+  @tag capture_log: true
+  test "whitelist caches specific named queries" do
+    assert [] = :get
+      |> conn(graphql_url(@whitelist_named_query))
+      |> RequestCache.Support.Utils.ensure_default_opts(request: [whitelisted_query_names: ["SmallHello"]])
+      |> Router.call([])
+      |> get_resp_header(RequestCache.Plug.request_cache_header())
+
+    assert ["HIT"] = :get
+      |> conn(graphql_url(@whitelist_named_query))
+      |> RequestCache.Support.Utils.ensure_default_opts(request: [whitelisted_query_names: ["SmallHello"]])
+      |> Router.call([])
+      |> get_resp_header(RequestCache.Plug.request_cache_header())
+  end
+
   defp graphql_url(query) do
     "/graphql?#{URI.encode_query(%{query: query})}"
   end