feat: web sdk example with topic client that refreshes disposable tokens

examples/nodejs/token-vending-machine/infrastructure/package.json

@@ -18,7 +18,7 @@
     "@types/jest": "^29.4.0",
     "@types/node": "18.11.18",
     "@typescript-eslint/eslint-plugin": "5.59.11",
-    "aws-cdk": "2.85.0",
+    "aws-cdk": "2.158.0",
     "eslint": "8.42.0",
     "eslint-config-prettier": "8.8.0",
     "eslint-plugin-import": "2.27.5",
@@ -31,7 +31,7 @@
     "typescript": "~4.9.4"
   },
   "dependencies": {
-    "aws-cdk-lib": "^2.85.0",
+    "aws-cdk-lib": "^2.158.0",
     "constructs": "^10.0.0",
     "source-map-support": "^0.5.21"
   }

examples/nodejs/token-vending-machine/lambda/token-vending-machine/handler.ts

@@ -36,6 +36,9 @@ export const handler = async (event: APIGatewayProxyEvent): Promise<APIGatewayPr
     console.log(err);
     return {
       statusCode: 500,
+      headers: {
+        "Access-Control-Allow-Origin": "*",
+      },
       body: JSON.stringify({
         message: 'An error occurred!',
       }),

examples/web/cache/README.template.md

@@ -46,6 +46,44 @@ MOMENTO_API_KEY=<YOUR API KEY> npm run dictionary
 
 Example Code: [dictionary.ts](dictionary.ts)
 
+## Running the TopicClient example with auto-refreshing disposable tokens
+
+This example implements TokenRefreshingTopicClient, an example wrapper class around the TopicClient that refreshes disposable tokens before they expire. Getting a new disposable token requires creating a new TopicClient that accepts a CredentialProvider that uses the new token. After the new TopicClient is created, existing subscriptions must be transferred to the new client. All of this occurs within the TokenRefreshingTopicClient. 
+
+If you run the example using the `localTokenVendingMachine()` method passed to the wrapped client (this is the default for this example):
+
+```typescript
+  const wrappedTopicClient = await TokenRefreshingTopicClient.create({
+    refreshBeforeExpiryMs: 10_000, // 10 seconds before token expires, refresh it.
+    getDisposableToken: localTokenVendingMachine,
+  });
+```
+
+Run the example using:
+
+```bash
+# Run example code
+MOMENTO_API_KEY=<YOUR API KEY> npm run tokens
+```
+
+If you have deployed a token vending machine to generate disposable tokens like so:
+
+```typescript
+  const wrappedTopicClient = await TokenRefreshingTopicClient.create({
+    refreshBeforeExpiryMs: 10_000, // 10 seconds before token expires, refresh it.
+    getDisposableToken: tokenVendingMachine,
+  });
+```
+
+Run the example using:
+
+```bash
+# Run example code
+TVM_ENDPOINT=<YOUR TVM URL> npm run tokens
+```
+
+Example Code: [refresh-disposable-tokens.ts](refresh-disposable-tokens.ts)
+
 If you have questions or need help experimenting further, please reach out to us!
 
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