From 608c951b5b9bde26395d539ed226f4a72f5f151d Mon Sep 17 00:00:00 2001
From: Hugo Morosini <hugo.morosini@gmail.com>
Date: Tue, 26 Oct 2021 14:32:09 +0200
Subject: [PATCH] added expiration logic

---
 src/nft/NftMetadataProvider/index.tsx | 11 ++++++-----
 src/nft/NftMetadataProvider/logic.ts  | 20 ++++++++++++++++++++
 src/nft/NftMetadataProvider/types.ts  |  1 +
 3 files changed, 27 insertions(+), 5 deletions(-)
 create mode 100644 src/nft/NftMetadataProvider/logic.ts

diff --git a/src/nft/NftMetadataProvider/index.tsx b/src/nft/NftMetadataProvider/index.tsx
index 1bdbc44197..f5fe70cde7 100644
--- a/src/nft/NftMetadataProvider/index.tsx
+++ b/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",
diff --git a/src/nft/NftMetadataProvider/logic.ts b/src/nft/NftMetadataProvider/logic.ts
new file mode 100644
index 0000000000..58939e8af8
--- /dev/null
+++ b/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;
+}
diff --git a/src/nft/NftMetadataProvider/types.ts b/src/nft/NftMetadataProvider/types.ts
index 15b3baeae8..935d7e1a97 100644
--- a/src/nft/NftMetadataProvider/types.ts
+++ b/src/nft/NftMetadataProvider/types.ts
@@ -22,6 +22,7 @@ export type NFTResourceError = {
 
 export type NFTResourceNoData = {
   status: "nodata";
+  updatedAt: number;
 };
 
 export type NFTResource =