Fix: Add support for revalidateTag (#145)

* feat: add revalidateTag handling

* fix: do not override tags on page set

* fix: force revalidation for stale tags and write meta for page

* fix: patch fetch function

* fix for 13.4.20

* add docs to help retrieve paths

* custom provider to populate dynamodb

* fix for esm loader

* fix for next bundled 13.5

* revert serverHandler to use custom routing

* remove patchFetch as it no longer works

* docs: add docs about fetch behaviour

* get fetch cache tags directly from cache file

Author: conico974

README.md

@@ -329,7 +329,35 @@ await invalidateCFPaths(["/page/a", "/page/b", "/page/c"]);
 await invalidateCFPaths(["/page/*"]);
 ```
 
-Please note that on-demand revalidation via the [`next/cache` module](https://nextjs.org/docs/app/building-your-application/data-fetching/revalidating#using-on-demand-revalidation) (`revalidatePath` and `revalidateTag`) is not yet supported.
+For on-demand revalidation via the [`next/cache` module](https://nextjs.org/docs/app/building-your-application/data-fetching/revalidating#using-on-demand-revalidation), if you want to retrieve the associated paths for a given tag, you can use this function:
+
+```ts
+function getByTag(tag: string) {
+  try {
+    const { Items } = await this.dynamoClient.send(
+      new QueryCommand({
+        TableName: process.env.CACHE_DYNAMO_TABLE,
+        KeyConditionExpression: "#tag = :tag",
+        ExpressionAttributeNames: {
+          "#tag": "tag",
+        },
+        ExpressionAttributeValues: {
+          ":tag": { S: `${process.env.NEXT_BUILD_ID}/${tag}` },
+        },
+      }),
+    );
+    return (
+      // We need to remove the buildId from the path
+      Items?.map(
+        ({ path: { S: key } }) => key?.replace(`${process.env.NEXT_BUILD_ID}/`, "") ?? "",
+      ) ?? []
+    );
+  } catch (e) {
+    error("Failed to get by tag", e);
+    return [];
+  }
+}
+```
 
 ## How warming works
 
@@ -383,6 +411,19 @@ This cost estimate is based on the `us-east-1` region pricing and does not consi
 
 ## Limitations and workarounds
 
+#### WORKAROUND: Patch fetch behaviour for ISR. Only for [email protected]+
+
+In order to make fetch work as expected with ISR, you need to patch the `fetch` function in your app. Just add this lines to your root layout component:
+
+```ts
+const asyncStorage = require("next/dist/client/components/static-generation-async-storage.external");
+//@ts-ignore
+const staticStore = (fetch as any).__nextGetStaticStore?.() || asyncStorage.staticGenerationAsyncStorage;
+const store = staticStore.getStore();
+store.isOnDemandRevalidate = store.isOnDemandRevalidate && !(process.env.OPEN_NEXT_ISR === 'true');
+```
+Without this workaround, if you have 2 fetch calls in your page with different revalidate values, both will use the smallest value during ISR revalidation.
+
 #### WORKAROUND: Create one cache behavior per top-level file and folder in `public/` (AWS specific)
 
 As mentioned in the [Asset files](#asset-files) section, files in your app's `public/` folder are static and are uploaded to the S3 bucket. And requests for these files are handled by the S3 bucket, like so:

packages/open-next/package.json

@@ -34,6 +34,7 @@
     "README.md"
   ],
   "dependencies": {
+    "@aws-sdk/client-dynamodb": "^3.398.0",
     "@aws-sdk/client-lambda": "^3.398.0",
     "@aws-sdk/client-s3": "^3.398.0",
     "@aws-sdk/client-sqs": "^3.398.0",