Merge pull request #267606 from ggailey777/madhura

[Functions] New HTTP streams for node.js

Author: AnnaMHuff

articles/azure-functions/functions-bindings-http-webhook-trigger.md

@@ -189,7 +189,7 @@ This example reads the body of a POST request, as a `String`, and uses it to bui
 
 #### Read parameter from a route
 
-This example reads a mandatory parameter, named `id`, and an optional parameter `name` from the route path, and uses them to build a JSON document returned to the client, with content type `application/json`. T
+This example reads a mandatory parameter, named `id`, and an optional parameter `name` from the route path, and uses them to build a JSON document returned to the client, with content type `application/json`.
 
 ```java
 @FunctionName("TriggerStringRoute")
@@ -1004,6 +1004,12 @@ When you use route parameters, an `invoke_URL_template` is automatically created
 
 You can programmatically access the `invoke_URL_template` by using the Azure Resource Manager APIs for [List Functions](/rest/api/appservice/webapps/listfunctions) or [Get Function](/rest/api/appservice/webapps/getfunction).
 
+::: zone pivot="programming-language-javascript,programming-language-typescript"  
+### HTTP streams (preview)
+
+You can now stream requests to and responses from your HTTP endpoint in Node.js v4 function apps. For more information, see [HTTP streams](functions-reference-node.md?pivots=nodejs-model-v4#http-streams-preview).   
+::: zone-end  
+
 ### Working with client identities
 
 If your function app is using [App Service Authentication / Authorization](../app-service/overview-authentication-authorization.md), you can view information about authenticated clients from your code. This information is available as [request headers injected by the platform](../app-service/configure-authentication-user-identities.md#access-user-claims-in-app-code).

articles/azure-functions/functions-reference-node.md

@@ -3,7 +3,7 @@ title: Node.js developer reference for Azure Functions
 description: Understand how to develop functions by using Node.js.
 ms.assetid: 45dedd78-3ff9-411f-bb4b-16d29a11384c
 ms.topic: conceptual
-ms.date: 04/17/2023
+ms.date: 02/28/2024
 ms.devlang: javascript
 # ms.devlang: javascript, typescript
 ms.custom: devx-track-js, vscode-azure-extension-update-not-needed
@@ -33,8 +33,8 @@ The following table shows each version of the Node.js programming model along wi
 | ---- | ---- | --- | --- | --- |
 | 4.x | GA | 4.25+ | 20.x (Preview), 18.x | Supports a flexible file structure and code-centric approach to triggers and bindings. |
 | 3.x | GA | 4.x | 20.x (Preview), 18.x, 16.x, 14.x | Requires a specific file structure with your triggers and bindings declared in a "function.json" file |
-| 2.x | GA (EOL) | 3.x | 14.x, 12.x, 10.x | Reached end of life (EOL) on December 13, 2022. See [Functions Versions](./functions-versions.md) for more info. |
-| 1.x | GA (EOL) | 2.x | 10.x, 8.x | Reached end of life (EOL) on December 13, 2022. See [Functions Versions](./functions-versions.md) for more info. |
+| 2.x | n/a | 3.x | 14.x, 12.x, 10.x | Reached end of support on December 13, 2022. See [Functions Versions](./functions-versions.md) for more info. |
+| 1.x | n/a | 2.x | 10.x, 8.x | Reached end of support on December 13, 2022. See [Functions Versions](./functions-versions.md) for more info. |
 
 ## Folder structure
 
@@ -730,7 +730,7 @@ app.storageQueue('copyBlob1', {
 
 ### Generic inputs and outputs
 
-The `app`, `trigger`, `input`, and `output` objects exported by the `@azure/functions` module provide type-specific methods for most types. For all the types that aren't supported, a `generic` method has been provided to allow you to manually specify the configuration. The `generic` method can also be used if you want to change the default settings provided by a type-specific method.
+The `app`, `trigger`, `input`, and `output` objects exported by the `@azure/functions` module provide type-specific methods for most types. For all the types that aren't supported, a `generic` method is provided to allow you to manually specify the configuration. The `generic` method can also be used if you want to change the default settings provided by a type-specific method.
 
 The following example is a simple HTTP triggered function using generic methods instead of type-specific methods.
 
@@ -1222,7 +1222,7 @@ The `HttpRequest` object has the following properties:
 | **`params`**   | `Record<string, string>` | Route parameter keys and values. |
 | **`user`**     | `HttpRequestUser | null` | Object representing logged-in user, either through Functions authentication, SWA Authentication, or null when no such user is logged in. |
 | **`body`**     | [`ReadableStream | null`](https://developer.mozilla.org/docs/Web/API/ReadableStream) | Body as a readable stream. |
-| **`bodyUsed`** | `boolean` | A boolean indicating if the body has been read from already. |
+| **`bodyUsed`** | `boolean` | A boolean indicating if the body is already read. |
 
 In order to access a request or response's body, the following methods can be used:
 
@@ -1422,6 +1422,85 @@ The response can be set in several ways:
 
 ::: zone-end
 
+## HTTP streams (preview)
+
+HTTP streams is a feature that makes it easier to process large data, stream OpenAI responses, deliver dynamic content, and support other core HTTP scenarios. It lets you stream requests to and responses from HTTP endpoints in your Node.js function app. Use HTTP streams in scenarios where your app requires real-time exchange and interaction between client and server over HTTP. You can also use HTTP streams to get the best performance and reliability for your apps when using HTTP.
+
+HTTP streams is currently in preview.
+
+::: zone pivot="nodejs-model-v3"  
+>[!IMPORTANT]
+>HTTP streams aren't supported in the v3 model. [Upgrade to the v4 model](./functions-node-upgrade-v4.md) to use the HTTP streaming feature.
+::: zone-end  
+::: zone pivot="nodejs-model-v4"  
+The existing `HttpRequest` and `HttpResponse` types in programming model v4 already support various ways of handling the message body, including as a stream. 
+ 
+### Prerequisites
+- The [`@azure/functions` npm package](https://www.npmjs.com/package/@azure/functions) version 4.3.0 or later.
+- [Azure Functions runtime](./functions-versions.md) version 4.28 or later. 
+- [Azure Functions Core Tools](./functions-run-local.md) version 4.0.5530 or a later version, which contains the correct runtime version. 
+
+### Enable streams
+
+Use these steps to enable HTTP streams in your function app in Azure and in your local projects:
+
+1. If you plan to stream large amounts of data, modify the [`FUNCTIONS_REQUEST_BODY_SIZE_LIMIT`](./functions-app-settings.md#functions_request_body_size_limit) setting in Azure. The default maximum body size allowed is `104857600`, which limits your requests to a size of ~100 MB.
+
+1. For local development, also add `FUNCTIONS_REQUEST_BODY_SIZE_LIMIT` to the [local.settings.json file](./functions-develop-local.md#local-settings-file).
+
+1. Add the following code to your app in any file included by your [main field](./functions-reference-node.md#registering-a-function).
+
+    #### [JavaScript](#tab/javascript)
+    
+    ```javascript
+    const { app } = require('@azure/functions'); 
+    
+    app.setup({ enableHttpStream: true });
+    ```
+
+    #### [TypeScript](#tab/typescript)
+    
+    ```typescript
+    import { app } from '@azure/functions'; 
+    
+    app.setup({ enableHttpStream: true }); 
+    ```
+    
+    ---
+
+### Stream examples
+
+This example shows an HTTP triggered function that receives data via an HTTP POST request, and the function streams this data to a specified output file: 
+
+#### [JavaScript](#tab/javascript)
+
+:::code language="javascript" source="~/azure-functions-nodejs-v4/js/src/functions/httpTriggerStreamRequest.js" :::
+
+#### [TypeScript](#tab/typescript)
+
+:::code language="typescript" source="~/azure-functions-nodejs-v4/ts/src/functions/httpTriggerStreamRequest.ts" :::
+
+---
+
+This example shows an HTTP triggered function that streams a file's content as the response to incoming HTTP GET requests: 
+
+#### [JavaScript](#tab/javascript)
+
+:::code language="javascript" source="~/azure-functions-nodejs-v4/js/src/functions/httpTriggerStreamResponse.js" :::
+
+#### [TypeScript](#tab/typescript)
+
+:::code language="typescript" source="~/azure-functions-nodejs-v4/ts/src/functions/httpTriggerStreamResponse.ts" :::
+  
+---
+
+### Stream considerations
+
++ The `request.params` object isn't supported when using HTTP streams during preview. Refer to this [GitHub issue](https://github.com/Azure/azure-functions-nodejs-library/issues/229) for more information and suggested workaround.
+
++ Use `request.body` to obtain the maximum benefit from using streams. You can still continue to use methods like `request.text()`, which always return the body as a string.
+::: zone-end  
+
 ## Hooks
 
 ::: zone pivot="nodejs-model-v3"