added expiration logic

src/nft/NftMetadataProvider/index.tsx

@@ -17,6 +17,7 @@ import {
   NFTMetadataContextType,
   NFTResource,
 } from "./types";
+import { isOutdated } from "./logic";
 
 const currency: Currency = findCryptoCurrencyById("ethereum")!;
 const ethApi: API = apiForCurrency(currency);
@@ -81,16 +82,16 @@ export function useNftMetadata(contract: string, tokenId: string): NFTResource {
 
   const key = getNftKey(contract, tokenId);
 
-  const cached = cache[key];
+  const cachedData = cache[key];
 
   useEffect(() => {
-    if (!cached) {
+    if (!cachedData || isOutdated(cachedData)) {
       loadNFTMetadata(contract, tokenId);
     }
-  }, [contract, tokenId, cached, loadNFTMetadata]);
+  }, [contract, tokenId, cachedData, loadNFTMetadata]);
 
-  if (cached) {
-    return cached;
+  if (cachedData) {
+    return cachedData;
   } else {
     return {
       status: "queued",

src/nft/NftMetadataProvider/logic.ts

@@ -0,0 +1,20 @@
+import { NFTResource } from "./types";
+
+// Handle lifecycle of cached data.
+// Expiration date depend on the resource's status.
+export function isOutdated(resource: NFTResource): boolean {
+  const now = Date.now();
+
+  switch (resource.status) {
+    case "loaded": {
+      return now - resource.updatedAt > 14 * 24 * 60 * 60 * 1 * 1000; // 14 days
+    }
+    case "error": {
+      return now - resource.updatedAt > 1 * 1000; // 1 second
+    }
+    case "nodata": {
+      return now - resource.updatedAt > 24 * 60 * 60 * 1 * 1000; // 1 day
+    }
+  }
+  return false;
+}

src/nft/NftMetadataProvider/types.ts

@@ -22,6 +22,7 @@ export type NFTResourceError = {
 
 export type NFTResourceNoData = {
   status: "nodata";
+  updatedAt: number;
 };
 
 export type NFTResource =