feat: add support for AWS lambda (#252)

Author: suneettipirneni

package-lock.json

@@ -0,0 +1 @@
+export * from "./src/aws.js";

packages/discord-verify/aws.ts

@@ -1,7 +1,7 @@
 import { defineBuildConfig } from "unbuild";
 
 export default defineBuildConfig({
-	entries: ["./node", "./web"],
+	entries: ["./node", "./web", "./aws"],
 	rollup: {
 		emitCJS: true,
 	},

packages/discord-verify/build.config.ts

@@ -20,6 +20,11 @@
 			"import": "./dist/node.mjs",
 			"require": "./dist/node.cjs",
 			"types": "./dist/node.d.ts"
+		},
+		"./aws": {
+			"import": "./dist/aws.mjs",
+			"require": "./dist/aws.cjs",
+			"types": "./dist/aws.d.ts"
 		}
 	},
 	"main": "./dist/web.mjs",

packages/discord-verify/package.json

@@ -0,0 +1,52 @@
+// AWS lambda requires an explicit crypto import.
+// eslint-disable-next-line @typescript-eslint/ban-ts-comment, @typescript-eslint/prefer-ts-expect-error
+// @ts-ignore-error We can't use Node types since we aren't fully in a Node environment
+import crypto from "crypto";
+import { PlatformAlgorithm, verify } from "./lib/verify.js";
+
+export interface AWSGatewayEvent {
+	headers: Record<string, string>;
+	body: string;
+}
+
+/**
+ * Validates a request from Discord received via AWS lambda.
+ * @param event - The AWS Gateway event to verify
+ * @param publicKey - The application's public key
+ * @param algorithm - The name of the crypto algorithm to use
+ * @returns Whether the request is valid or not
+ */
+export async function isValid(
+	event: AWSGatewayEvent,
+	publicKey: string,
+	algorithm?: string
+) {
+	const signature = event.headers["X-Signature-Ed25519"];
+	const timestamp = event.headers["X-Signature-Timestamp"];
+	const { body } = event;
+	if (!signature || !timestamp || !body) return false;
+
+	try {
+		await verify(
+			event.body,
+			signature,
+			timestamp,
+			publicKey,
+			crypto.webcrypto.subtle,
+			algorithm ?? PlatformAlgorithm.OldNode
+		);
+	} catch (error: unknown) {
+		if (error instanceof Error && error.constructor.name === "DOMException") {
+			return verify(
+				event.body,
+				signature,
+				timestamp,
+				publicKey,
+				crypto.webcrypto.subtle,
+				algorithm ?? PlatformAlgorithm.OldNode
+			);
+		}
+
+		throw error;
+	}
+}

packages/discord-verify/src/aws.ts

@@ -18,6 +18,13 @@
 		"target": "ES2021",
 		"moduleResolution": "NodeNext"
 	},
-	"include": ["src/**/*.ts", "node.ts", "node.cts", "web.ts"],
+	"include": [
+		"src/**/*.ts",
+		"node.ts",
+		"node.cts",
+		"web.ts",
+		"aws.ts",
+		"aws.cts"
+	],
 	"exclude": ["node_modules", "dist", "*.js"]
 }