new article - parameter based routing

articles/application-gateway/parameter-based-path-selection-portal.md

@@ -0,0 +1,60 @@
+---
+title: Route traffic using parameter based path selection in portal - Azure Application Gateway
+description: Learn how to use the Azure portal to configure an Azure Application Gateway to choose the backend pool based on the value of a header, part of URL, or query string in the request.
+services: application-gateway
+author: greg-lindsay
+ms.service: azure-application-gateway
+ms.topic: how-to
+ms.date: 09/10/2024
+ms.author: greglin
+ms.custom: mvc
+---
+# Perform parameter based path selection with Azure Application Gateway - Azure portal
+
+This article describes how to use the Azure portal to configure an [Application Gateway v2 SKU](./application-gateway-autoscaling-zone-redundant.md) instance to perform parameter based path selection by combining the capabilities of URL Rewrite with path-based routing.
+
+If you don't have an Azure subscription, create a [free account](https://azure.microsoft.com/free/?WT.mc_id=A261C142F) before you begin.
+
+## Before you begin
+
+You need to have an Application Gateway v2 SKU instance to complete the steps in this article. URL rewrite and rewriting headers isn't supported in the v1 SKU. If you don't have the v2 SKU, create an [Application Gateway v2 SKU](./tutorial-autoscale-ps.md) instance before you begin.
+
+
+## Sign in to Azure
+
+Sign in to the [Azure portal](https://portal.azure.com/) with your Azure account.
+
+## Configure parameter based path selection
+
+For this example, you have a shopping website and the product category is passed as query string in the URL, and you want to route the request to backend based on the query string, then:
+
+**Step 1:**  Create a path-map as shown in the image below
+
+:::image type="content" source="./media/rewrite-http-headers-url/url-scenario1-1.png" alt-text="URL rewrite scenario 1-1.":::
+
+**Step 2 (a):** Create a rewrite set which has 3 rewrite rules: 
+
+* The first rule has a condition that checks the *query_string* variable for *category=shoes* and has an action that rewrites the URL path to /*listing1* and has **Reevaluate path map** enabled
+
+* The second rule has a condition that checks the *query_string* variable for *category=bags* and has an action that rewrites the URL path to /*listing2*  and has **Reevaluate path map** enabled
+
+* The third rule has a condition that checks the *query_string* variable for *category=accessories* and has an action that rewrites the URL path to /*listing3* and has **Reevaluate path map** enabled
+
+:::image type="content" source="./media/rewrite-http-headers-url/url-scenario1-2.png" alt-text="URL rewrite scenario 1-2.":::
+
+
+
+**Step 2 (b):** Associate this rewrite set with the default path of the above path-based rule
+
+:::image type="content" source="./media/rewrite-http-headers-url/url-scenario1-3.png" alt-text="URL rewrite scenario 1-3.":::
+
+If the user requests *contoso.com/listing?category=any*, then it's matched with the default path since none of the path patterns in the path map (/listing1, /listing2, /listing3) are matched. Since you associated the previous rewrite set with this path, this rewrite set is evaluated. Because the query string won't match the condition in any of the 3 rewrite rules in this rewrite set, no rewrite action takes place. Therefore, the request is routed unchanged to the backend associated with the default path (which is *GenericList*).
+
+If the user requests *contoso.com/listing?category=shoes*, then the default path is matched. However, in this case the condition in the first rule matches. Therefore, the action associated with the condition is executed, which rewrites the URL path to /*listing1*  and reevaluates the path-map. When the path-map is reevaluated, the request matches the path associated with pattern */listing1* and the request is routed to the backend associated with this pattern (ShoesListBackendPool).
+
+> [!NOTE]
+> This scenario can be extended to any header or cookie value, URL path, query string or server variables based on the conditions defined and essentially enables you to route requests based on those conditions.
+
+## Next steps
+
+To learn more about how to set up some common use cases, see [common header rewrite scenarios](./rewrite-http-headers-url.md).

articles/application-gateway/rewrite-http-headers-url.md

@@ -4,7 +4,7 @@ description: This article provides an overview of rewriting HTTP headers and URL
 author: greg-lindsay
 ms.service: azure-application-gateway
 ms.topic: conceptual
-ms.date: 09/06/2024
+ms.date: 09/10/2024
 ms.author: greglin
 ---
 
@@ -229,34 +229,12 @@ You can evaluate an HTTP request or response header for the presence of a header
 
 #### Parameter based path selection
 
-To accomplish scenarios where you want to choose the backend pool based on the value of a header, part of the URL, or query string in the request, you can use the combination of URL Rewrite capability and path-based routing. For example, if you have a shopping website and the product category is passed as query string in the URL, and you want to route the request to backend based on the query string, then:
+To accomplish scenarios where you want to choose the backend pool based on the value of a header, part of the URL, or query string in the request, you can use a combination of URL Rewrite capability and path-based routing. 
 
-**Step1:**  Create a path-map as shown in the image below
+To do this, you will have to create a rewrite set with a condition that checks for a specific parameter (query string, header, etc.) and then perform an action where it changes the URL path (ensure **Reevaluate path map** is enabled). This rewrite set will then be associated to a path based rule that assigns backend pools based on those same URL paths. Since "Reevaluate path map" is enabled, traffic will be routed based on the path specified in the rewrite set. 
 
-:::image type="content" source="./media/rewrite-http-headers-url/url-scenario1-1.png" alt-text="URL rewrite scenario 1-1.":::
+For a use case example using query strings, please see [Route traffic using parameter based path selection in portal](parameter-based-path-selection-portal.md).
 
-**Step 2 (a):** Create a rewrite set which has 3 rewrite rules: 
-
-* The first rule has a condition that checks the *query_string* variable for *category=shoes* and has an action that rewrites the URL path to /*listing1* and has **Reevaluate path map** enabled
-
-* The second rule has a condition that checks the *query_string* variable for *category=bags* and has an action that rewrites the URL path to /*listing2*  and has **Reevaluate path map** enabled
-
-* The third rule has a condition that checks the *query_string* variable for *category=accessories* and has an action that rewrites the URL path to /*listing3* and has **Reevaluate path map** enabled
-
-:::image type="content" source="./media/rewrite-http-headers-url/url-scenario1-2.png" alt-text="URL rewrite scenario 1-2.":::
-
-
-
-**Step 2 (b):** Associate this rewrite set with the default path of the above path-based rule
-
-:::image type="content" source="./media/rewrite-http-headers-url/url-scenario1-3.png" alt-text="URL rewrite scenario 1-3.":::
-
-If the user requests *contoso.com/listing?category=any*, then it's matched with the default path since none of the path patterns in the path map (/listing1, /listing2, /listing3) are matched. Since you associated the previous rewrite set with this path, this rewrite set is evaluated. Because the query string won't match the condition in any of the 3 rewrite rules in this rewrite set, no rewrite action takes place. Therefore, the request is routed unchanged to the backend associated with the default path (which is *GenericList*).
-
-If the user requests *contoso.com/listing?category=shoes*, then the default path is matched. However, in this case the condition in the first rule matches. Therefore, the action associated with the condition is executed, which rewrites the URL path to /*listing1*  and reevaluates the path-map. When the path-map is reevaluated, the request matches the path associated with pattern */listing1* and the request is routed to the backend associated with this pattern (ShoesListBackendPool).
-
-> [!NOTE]
-> This scenario can be extended to any header or cookie value, URL path, query string or server variables based on the conditions defined and essentially enables you to route requests based on those conditions.
 
 #### Rewrite query string parameters based on the URL
 

articles/application-gateway/toc.yml

@@ -271,6 +271,10 @@
       items:
         - name: Azure portal
           href: rewrite-url-portal.md
+    - name: Parameter based routing
+      items:
+        - name: Azure portal
+          href: parameter-based-path-selection-portal.md
   - name: Configure custom probes
     items:
       - name: Portal