Refined PM content

Author: flang-msft

articles/azure-cache-for-redis/cache-nodejs-get-started.md

@@ -17,38 +17,47 @@ In this quickstart, you incorporate Azure Cache for Redis into a Node.js app to
 ## Prerequisites
 
 - Azure subscription - [create one for free](https://azure.microsoft.com/free/)
-- Node.js installed, if you haven't done so already. See [Install Node.js on Windows](../../windows/dev-environment/javascript/nodejs-on-windows) for instructions on how to install Node and NPM on a Windows machine.
+- Node.js installed, if you haven't done so already. See [Install Node.js on Windows](/windows/dev-environment/javascript/nodejs-on-windows) for instructions on how to install Node and Node Package Manager (NPM) on a Windows computer.
 
 ## Create a cache
 
 [!INCLUDE [redis-cache-create](~/reusable-content/ce-skilling/azure/includes/azure-cache-for-redis/includes/redis-cache-create.md)]
 
-## Install the node-redis client lbirary
+## Install the node-redis client library
+
 The [node-redis](https://github.com/redis/node-redis) library is the primary Node.js client for Redis. You can install the client with [npm](https://docs.npmjs.com/about-npm) by using the following command:
 
 ```bash
 npm install redis
 ```
 
-## [Microsoft EntraID Authentication (recommended)](#tab/entraid)
+## [Microsoft Entra ID Authentication (recommended)](#tab/entraid)
+
+### Enable Microsoft Entra ID and add a User or Service Principal
+
+[!INCLUDE cache-entra-access]
 
-## Enable Microsoft EntraID and add a User or Service Principal
-<--Fran, we probably need an include file on enabling EntraID-->
-Blah blah blah, do the steps listed [here](cache-azure-active-directory-for-authentication)
+### Install the JavaScript Azure Identity client library
 
-## Install the JavaScript Azure Identity client library
-The [Microsoft Authentication Library (MSAL)](../../entra/identity-platform/msal-overview) allows you to acquire security tokens from Microsoft identity to authenticate users. There's a [Javascript Azure identity client library](../../javascript/api/overview/azure/identity-readme) available that uses MSAL to provide token authentication support. Install this library using `npm`:
+The [Microsoft Authentication Library (MSAL)](/entra/identity-platform/msal-overview) allows you to acquire security tokens from Microsoft identity to authenticate users. There's a [JavaScript Azure identity client library](/javascript/api/overview/azure/identity-readme) available that uses MSAL to provide token authentication support. Install this library using `npm`:
 
 ```bash
 npm install @azure/identity
 ```
 
-## Create a new Node.js app
+### Create a new Node.js app using Microsoft Entra ID
+
+1.Add environment variables for your **Host name** and **Service Principal ID**, which is the object ID your Microsoft Entra ID service principal or user. In the Azure portal, this is shown as the _Username_.
 
-1. Create a new script file named *redistest.js*.
+```cmd
+set AZURE_CACHE_FOR_REDIS_HOST_NAME=contosoCache
+set REDIS_SERVICE_PRINCIPAL_ID=XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
+```
+
+1. Create a new script file named _redistest.js_.
 1. Add the following example JavaScript to the file.
-   
-```node
+
+```javascript
 const { createClient } = require("redis");
 const { DefaultAzureCredential } = require("@azure/identity");
 
@@ -63,9 +72,9 @@ async function main() {
 
   // Create redis client and connect to the Azure Cache for Redis over the TLS port using the access token as password.
   const cacheConnection = createClient({
-    username: process.env.REDIS_SERVICE_PRINCIPAL_NAME,
+    username: process.env.REDIS_SERVICE_PRINCIPAL_ID,
     password: accessToken.token,
-    url: `redis://${process.env.REDIS_HOSTNAME}:6380`,
+    url: `redis://${process.env.AZURE_CACHE_FOR_REDIS_HOST_NAME}:6380`,
     pingInterval: 100000,
     socket: { 
       tls: true,
@@ -130,6 +139,115 @@ This code shows you how to connect to an Azure Cache for Redis instance using th
     Done
     ```
 
+## Create a sample JavaScript app with reauthentication
+
+Microsoft Entra ID access tokens have a limited lifespan, [averaging 75 minutes](../../entra/identity-platform/configurable-token-lifetimes#token-lifetime-policies-for-access-saml-and-id-tokens). In order to maintain a connection to your cache, you need to refresh the token. This example demonstrates how to do this using JavaScript.
+
+1. Create a new script file named _redistestreauth.js_.
+1. Add the following example JavaScript to the file.
+
+```javascript
+const { createClient } = require("redis");
+const { DefaultAzureCredential } = require("@azure/identity");
+
+async function returnPassword(credential) {
+    const redisScope = "https://redis.azure.com/.default";
+
+    // Fetch a Microsoft Entra token to be used for authentication. This token will be used as the password.
+    return credential.getToken(redisScope);
+}
+
+async function main() {
+  // Construct a Token Credential from Identity library, e.g. ClientSecretCredential / ClientCertificateCredential / ManagedIdentityCredential, etc.
+  const credential = new DefaultAzureCredential();
+  let accessToken = await returnPassword(credential);
+
+  // Create redis client and connect to the Azure Cache for Redis over the TLS port using the access token as password.
+  let cacheConnection = createClient({
+    username: process.env.REDIS_SERVICE_PRINCIPAL_ID,
+    password: accessToken.token,
+    url: `redis://${process.env.AZURE_CACHE_FOR_REDIS_HOST_NAME}:6380`,
+    pingInterval: 100000,
+    socket: { 
+      tls: true,
+      keepAlive: 0 
+    },
+  });
+
+  cacheConnection.on("error", (err) => console.log("Redis Client Error", err));
+  await cacheConnection.connect();
+
+  for (let i = 0; i < 3; i++) {
+    try {
+        // PING command
+        console.log("\nCache command: PING");
+        console.log("Cache response : " + await cacheConnection.ping());
+
+        // SET
+        console.log("\nCache command: SET Message");
+        console.log("Cache response : " + await cacheConnection.set("Message",
+            "Hello! The cache is working from Node.js!"));
+
+        // GET
+        console.log("\nCache command: GET Message");
+        console.log("Cache response : " + await cacheConnection.get("Message"));
+
+        // Client list, useful to see if connection list is growing...
+        console.log("\nCache command: CLIENT LIST");
+        console.log("Cache response : " + await cacheConnection.sendCommand(["CLIENT", "LIST"]));
+      break;
+    } catch (e) {
+      console.log("error during redis get", e.toString());
+      if ((accessToken.expiresOnTimestamp <= Date.now())|| (redis.status === "end" || "close") ) {
+        await redis.disconnect();
+        accessToken = await returnPassword(credential);
+        cacheConnection = createClient({
+          username: process.env.REDIS_SERVICE_PRINCIPAL_ID,
+          password: accessToken.token,
+          url: `redis://${process.env.AZURE_CACHE_FOR_REDIS_HOST_NAME}:6380`,
+          pingInterval: 100000,
+          socket: {
+            tls: true,
+            keepAlive: 0
+          },
+        });
+      }
+    }
+  }
+}
+
+main().then((result) => console.log(result)).catch(ex => console.log(ex));
+```
+
+1. Run the script with Node.js.
+
+    ```bash
+    node redistestreauth.js
+    ```
+
+1. Example the output.
+
+    ```console
+    Cache command: PING
+    Cache response : PONG
+    
+    Cache command: GET Message
+    Cache response : Hello! The cache is working from Node.js!
+    
+    Cache command: SET Message
+    Cache response : OK
+    
+    Cache command: GET Message
+    Cache response : Hello! The cache is working from Node.js!
+    
+    Cache command: CLIENT LIST
+    Cache response : id=10017364 addr=76.22.73.183:59380 fd=221 name= age=1 idle=0 flags=N db=0 sub=0 psub=0 multi=-1 qbuf=26 qbuf-free=32742 argv-mem=10 obl=0 oll=0 omem=0 tot-mem=61466 ow=0 owmem=0 events=r cmd=client user=default numops=6
+   ```
+
+>[!NOTE]
+>For additional examples of using Microsoft Entra ID to authenticate to Redis using the node-redis library, please see [this GitHub repo](https://github.com/Azure/azure-sdk-for-js/blob/main/sdk/identity/identity/samples/AzureCacheForRedis/node-redis.md)
+>
+
 ## [Access Key Authentication](#tab/accesskey)
 
 [!INCLUDE [redis-cache-access-keys](includes/redis-cache-access-keys.md)]
@@ -149,7 +267,7 @@ set AZURE_CACHE_FOR_REDIS_ACCESS_KEY=XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
 
 ## Create a new Node.js app
 
-1. Create a new script file named *redistest.js*.
+1. Create a new script file named _redistest.js_.
 1. Add the following example JavaScript to the file.
 
     ```javascript
@@ -232,6 +350,7 @@ set AZURE_CACHE_FOR_REDIS_ACCESS_KEY=XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
     
     Done
     ```
+
 ---
 
 ## Clean up resources
@@ -244,7 +363,7 @@ If you continue to the next tutorial, can keep the resources created in this qui
 
 1. Sign in to the [Azure portal](https://portal.azure.com) and select **Resource groups**.
 
-1. In the **Filter by name** text box, enter the name of your resource group. The instructions for this article used a resource group named *TestResources*. On your resource group in the result list, select **...** then **Delete resource group**.
+1. In the **Filter by name** text box, enter the name of your resource group. The instructions for this article used a resource group named _TestResources_. On your resource group in the result list, select **...** then **Delete resource group**.
 
     ![Delete Azure Resource group](./media/cache-nodejs-get-started/redis-cache-delete-resource-group.png)
 
@@ -256,9 +375,8 @@ If you continue to the next tutorial, can keep the resources created in this qui
 
 Get the [Node.js quickstart](https://github.com/Azure-Samples/azure-cache-redis-samples/tree/main/quickstart/nodejs) on GitHub.
 
-## Next steps
+## Related content
 
 In this quickstart, you learned how to use Azure Cache for Redis from a Node.js application. Continue to the next quickstart to use Azure Cache for Redis with an ASP.NET web app.
 
-> [!div class="nextstepaction"]
-> [Create an ASP.NET web app that uses an Azure Cache for Redis.](./cache-web-app-howto.md)
+- [Create an ASP.NET web app that uses an Azure Cache for Redis.](./cache-web-app-howto.md)