Replace deprecated undici formData() method with @fastify/busboy implementation

package.json

@@ -41,11 +41,13 @@
         "watch": "webpack --watch --mode development"
     },
     "dependencies": {
+        "@fastify/busboy": "^3.1.1",
         "cookie": "^0.7.0",
         "long": "^4.0.0",
         "undici": "^7.10.0"
     },
     "devDependencies": {
+        "@types/busboy": "^1.5.4",
         "@types/chai": "^4.2.22",
         "@types/chai-as-promised": "^7.1.5",
         "@types/cookie": "^0.6.0",
@@ -65,8 +67,8 @@
         "eslint-plugin-header": "^3.1.1",
         "eslint-plugin-import": "^2.29.0",
         "eslint-plugin-prettier": "^4.0.0",
-        "eslint-webpack-plugin": "^3.2.0",
         "eslint-plugin-simple-import-sort": "^10.0.0",
+        "eslint-webpack-plugin": "^3.2.0",
         "fork-ts-checker-webpack-plugin": "^7.2.13",
         "fs-extra": "^10.0.1",
         "globby": "^11.0.0",

src/http/HttpRequest.ts

@@ -15,6 +15,7 @@ import { fromRpcTypedData } from '../converters/fromRpcTypedData';
 import { AzFuncSystemError } from '../errors';
 import { isDefined, nonNullProp } from '../utils/nonNull';
 import { extractHttpUserFromHeaders } from './extractHttpUserFromHeaders';
+import { parseFormData } from './formDataParser';
 
 interface InternalHttpRequestInit extends RpcHttpData {
     undiciRequest?: uRequest;
@@ -96,8 +97,7 @@ export class HttpRequest implements types.HttpRequest {
     }
 
     async formData(): Promise<FormData> {
-        // eslint-disable-next-line deprecation/deprecation
-        return this.#uReq.formData();
+        return parseFormData(this.#uReq.body, this.#uReq.headers);
     }
 
     async json(): Promise<unknown> {

src/http/HttpResponse.ts

@@ -7,6 +7,7 @@ import { Blob } from 'buffer';
 import { ReadableStream } from 'stream/web';
 import { FormData, Headers, Response as uResponse, ResponseInit as uResponseInit } from 'undici';
 import { isDefined } from '../utils/nonNull';
+import { parseFormData } from './formDataParser';
 
 interface InternalHttpResponseInit extends HttpResponseInit {
     undiciResponse?: uResponse;
@@ -63,8 +64,7 @@ export class HttpResponse implements types.HttpResponse {
     }
 
     async formData(): Promise<FormData> {
-        // eslint-disable-next-line deprecation/deprecation
-        return this.#uRes.formData();
+        return parseFormData(this.#uRes.body, this.#uRes.headers);
     }
 
     async json(): Promise<unknown> {

src/http/formDataParser.ts

@@ -0,0 +1,99 @@
+// Copyright (c) .NET Foundation. All rights reserved.
+// Licensed under the MIT License.
+
+import { Readable } from 'node:stream';
+import { Busboy } from '@fastify/busboy';
+import { ReadableStream } from 'stream/web';
+import { FormData, Headers } from 'undici';
+
+/**
+ * Parse form data from a ReadableStream using @fastify/busboy as recommended by undici
+ * This replaces the deprecated formData() method from undici
+ */
+export async function parseFormData(body: ReadableStream<any> | null, headers: Headers): Promise<FormData> {
+    if (!body) {
+        throw new TypeError('Cannot parse form data from null body');
+    }
+
+    const contentType = headers.get('content-type');
+    if (!contentType) {
+        throw new TypeError('Content-Type header is required for form data parsing');
+    }
+
+    // Check if content type is supported
+    const isMultipart = contentType.includes('multipart/form-data');
+    const isUrlEncoded = contentType.includes('application/x-www-form-urlencoded');
+
+    if (!isMultipart && !isUrlEncoded) {
+        throw new TypeError(
+            `Content-Type was not one of "multipart/form-data" or "application/x-www-form-urlencoded".`
+        );
+    }
+
+    // For URL-encoded data, we can parse it directly
+    if (isUrlEncoded) {
+        const readable = Readable.fromWeb(body);
+        const chunks: Buffer[] = [];
+
+        for await (const chunk of readable) {
+            if (Buffer.isBuffer(chunk)) {
+                chunks.push(chunk);
+            } else if (chunk instanceof Uint8Array) {
+                chunks.push(Buffer.from(chunk));
+            } else {
+                chunks.push(Buffer.from(String(chunk)));
+            }
+        }
+
+        const buffer = Buffer.concat(chunks);
+        const text = buffer.toString('utf-8');
+        const formData = new FormData();
+
+        const params = new URLSearchParams(text);
+        for (const [key, value] of params) {
+            formData.append(key, value);
+        }
+
+        return formData;
+    }
+
+    // For multipart data, use busboy
+    return new Promise((resolve, reject) => {
+        const formData = new FormData();
+        const readable = Readable.fromWeb(body);
+
+        const busboy = new Busboy({
+            headers: { 'content-type': contentType },
+        });
+
+        busboy.on('field', (fieldname, value) => {
+            formData.append(fieldname, value);
+        });
+
+        busboy.on('file', (fieldname, fileStream, filename, encoding, mimeType) => {
+            const chunks: Uint8Array[] = [];
+
+            fileStream.on('data', (chunk: Buffer) => {
+                chunks.push(chunk);
+            });
+
+            fileStream.on('end', () => {
+                const buffer = Buffer.concat(chunks);
+                const file = new File([buffer], filename || 'unknown', {
+                    type: mimeType || 'application/octet-stream',
+                });
+                formData.append(fieldname, file);
+            });
+
+            fileStream.on('error', reject);
+        });
+
+        busboy.on('error', reject);
+
+        busboy.on('finish', () => {
+            resolve(formData);
+        });
+
+        readable.pipe(busboy);
+    });
+}

types/InvocationContext.d.ts

@@ -129,7 +129,7 @@ export interface InvocationContextExtraInputs {
      * @input the configuration object for this SQL input
      */
     get(input: SqlInput): unknown;
-	
+
     /**
      * Get a secondary MySql items input for this invocation
      * @input the configuration object for this MySql input
@@ -223,7 +223,7 @@ export interface InvocationContextExtraOutputs {
      * @message the output event(s) value
      */
     set(output: EventGridOutput, events: EventGridPartialEvent | EventGridPartialEvent[]): void;
-	
+
     /**
      * Set a secondary MySql items output for this invocation
      * @output the configuration object for this MySql output

types/input.d.ts

@@ -4,10 +4,10 @@
 import { CosmosDBInput, CosmosDBInputOptions } from './cosmosDB';
 import { GenericInputOptions } from './generic';
 import { FunctionInput } from './index';
+import { MySqlInput, MySqlInputOptions } from './mySql';
 import { SqlInput, SqlInputOptions } from './sql';
 import { StorageBlobInput, StorageBlobInputOptions } from './storage';
 import { TableInput, TableInputOptions } from './table';
-import { MySqlInput, MySqlInputOptions } from './mySql';
 import {
     WebPubSubConnectionInput,
     WebPubSubConnectionInputOptions,

types/output.d.ts

@@ -7,6 +7,7 @@ import { EventHubOutput, EventHubOutputOptions } from './eventHub';
 import { GenericOutputOptions } from './generic';
 import { HttpOutput, HttpOutputOptions } from './http';
 import { FunctionOutput } from './index';
+import { MySqlOutput, MySqlOutputOptions } from './mySql';
 import {
     ServiceBusQueueOutput,
     ServiceBusQueueOutputOptions,
@@ -16,7 +17,6 @@ import {
 import { SqlOutput, SqlOutputOptions } from './sql';
 import { StorageBlobOutput, StorageBlobOutputOptions, StorageQueueOutput, StorageQueueOutputOptions } from './storage';
 import { TableOutput, TableOutputOptions } from './table';
-import { MySqlOutput, MySqlOutputOptions } from './mySql';
 import { WebPubSubOutput, WebPubSubOutputOptions } from './webpubsub';
 
 /**