From 0177ebafa9cc36dd3cb12ec4fe7b27985a91b5f2 Mon Sep 17 00:00:00 2001
From: Travis Fischer <fisch0920@gmail.com>
Date: Tue, 21 Jul 2020 08:31:51 -0400
Subject: [PATCH] feat: respect cache headers

---
 src/get-cache-key.ts | 16 ++++++++++++++++
 src/index.ts         | 20 ++++++++++++--------
 src/response.ts      |  1 +
 3 files changed, 29 insertions(+), 8 deletions(-)
 create mode 100644 src/get-cache-key.ts

diff --git a/src/get-cache-key.ts b/src/get-cache-key.ts
new file mode 100644
index 0000000..de8dec9
--- /dev/null
+++ b/src/get-cache-key.ts
@@ -0,0 +1,16 @@
+export function getCacheKey(request: Request): string | null {
+  const pragma = request.headers.get("pragma");
+  if (pragma === "no-cache") {
+    return null;
+  }
+
+  const cacheControl = request.headers.get("cache-control");
+  if (cacheControl) {
+    const directives = new Set(cacheControl.split(",").map((s) => s.trim()));
+    if (directives.has("no-store") || directives.has("no-cache")) {
+      return null;
+    }
+  }
+
+  return request.url;
+}
diff --git a/src/index.ts b/src/index.ts
index 0f9a31a..435ad32 100644
--- a/src/index.ts
+++ b/src/index.ts
@@ -6,6 +6,7 @@ import { tableRoute } from "./routes/table";
 import { userRoute } from "./routes/user";
 import { searchRoute } from "./routes/search";
 import { createResponse } from "./response";
+import { getCacheKey } from "./get-cache-key";
 import * as types from "./api/types";
 
 export type Handler = (
@@ -55,14 +56,14 @@ const handleRequest = async (fetchEvent: FetchEvent): Promise<Response> => {
     return new Response("Endpoint not found.", { status: 404 });
   }
 
-  const cacheKey = request.url;
+  const cacheKey = getCacheKey(request);
   let response;
-  try {
-    const cachedResponse = await cache.match(cacheKey);
-    if (cachedResponse) {
-      response = cachedResponse;
-    }
-  } catch (err) {}
+
+  if (cacheKey) {
+    try {
+      response = await cache.match(cacheKey);
+    } catch (err) {}
+  }
 
   const getResponseAndPersist = async () => {
     const res = await match.handler({
@@ -72,7 +73,10 @@ const handleRequest = async (fetchEvent: FetchEvent): Promise<Response> => {
       notionToken,
     });
 
-    await cache.put(cacheKey, res.clone());
+    if (cacheKey) {
+      await cache.put(cacheKey, res.clone());
+    }
+
     return res;
   };
 
diff --git a/src/response.ts b/src/response.ts
index 54809bc..90caf91 100644
--- a/src/response.ts
+++ b/src/response.ts
@@ -10,6 +10,7 @@ export const createResponse = (
     headers: {
       "Access-Control-Allow-Origin": "*",
       "Access-Control-Allow-Methods": "GET, OPTIONS",
+      "Content-Type": "application/json",
       ...headers,
     },
   });