refactor: move cache headers logic into reusable functions (#4533)

* refactor: move cache headers logic into reusable functions

* dev

---------

Co-authored-by: Alexandr <qwerty541zxc@gmail.com>

src/common/cache.js

@@ -1,4 +1,6 @@
-import { clampValue } from "./utils";
+// @ts-check
+
+import { clampValue, CONSTANTS } from "./utils.js";
 
 /**
  * Resolves the cache seconds based on the requested, default, min, and max values.
@@ -11,7 +13,7 @@ import { clampValue } from "./utils";
  * @returns {number} The resolved cache seconds.
  */
 const resolveCacheSeconds = ({ requested, def, min, max }) => {
-  let cacheSeconds = clampValue(parseInt(requested || def, 10), min, max);
+  let cacheSeconds = clampValue(isNaN(requested) ? def : requested, min, max);
 
   cacheSeconds = process.env.CACHE_SECONDS
     ? parseInt(process.env.CACHE_SECONDS, 10) || cacheSeconds
@@ -20,4 +22,32 @@ const resolveCacheSeconds = ({ requested, def, min, max }) => {
   return cacheSeconds;
 };
 
-export { resolveCacheSeconds };
+/**
+ * Sets the Cache-Control headers on the response object.
+ *
+ * @param {Object} res The response object.
+ * @param {number} cacheSeconds The cache seconds to set in the headers.
+ */
+const setCacheHeaders = (res, cacheSeconds) => {
+  res.setHeader(
+    "Cache-Control",
+    `max-age=${cacheSeconds}, s-maxage=${cacheSeconds}, stale-while-revalidate=${CONSTANTS.ONE_DAY}`,
+  );
+};
+
+/**
+ * Sets the Cache-Control headers for error responses on the response object.
+ *
+ * @param {Object} res The response object.
+ */
+const setErrorCacheHeaders = (res) => {
+  // Use lower cache period for errors.
+  res.setHeader(
+    "Cache-Control",
+    `max-age=${CONSTANTS.ERROR_CACHE_SECONDS}, ` +
+      `s-maxage=${CONSTANTS.ERROR_CACHE_SECONDS}, ` +
+      `stale-while-revalidate=${CONSTANTS.ONE_DAY}`,
+  );
+};
+
+export { resolveCacheSeconds, setCacheHeaders, setErrorCacheHeaders };