fix(miniflare): expose send_email in platform proxy (#13723)

Co-authored-by: devin-ai-integration[bot] <158243242+devin-ai-integration[bot]@users.noreply.github.com>

Author: edmundhung

.changeset/email-platform-proxy.md

@@ -0,0 +1,7 @@
+---
+"miniflare": patch
+---
+
+Expose `send_email` bindings from `getPlatformProxy()`
+
+Projects developing in Node can now access `send_email` bindings from the platform proxy. This supports the plain-object MessageBuilder API locally, so calls like `env.EMAIL.send({ from, to, subject, text })` no longer fail because the binding is missing.

packages/miniflare/src/plugins/email/index.ts

@@ -1,10 +1,12 @@
+import { mkdir } from "node:fs/promises";
+import path from "node:path";
 import EMAIL_MESSAGE from "worker:email/email";
 import SEND_EMAIL_BINDING from "worker:email/send_email";
 import { z } from "zod";
 import {
 	getUserBindingServiceName,
 	remoteProxyClientWorker,
-	WORKER_BINDING_SERVICE_LOOPBACK,
+	ProxyNodeBinding,
 } from "../shared";
 import type { Service, Worker_Binding } from "../../runtime";
 import type { Plugin, RemoteProxyConnectionString } from "../shared";
@@ -41,6 +43,8 @@ export const EmailOptionsSchema = z.object({
 
 export const EMAIL_PLUGIN_NAME = "email";
 const SERVICE_SEND_EMAIL_WORKER_PREFIX = `SEND-EMAIL-WORKER`;
+const EMAIL_DISK_SERVICE_NAME = `${EMAIL_PLUGIN_NAME}:disk`;
+const EMAIL_DISK_BINDING_NAME = "MINIFLARE_EMAIL_DISK";
 
 function buildJsonBindings(bindings: Record<string, any>): Worker_Binding[] {
 	return Object.entries(bindings).map(([name, value]) => ({
@@ -68,11 +72,32 @@ export const EMAIL_PLUGIN: Plugin<typeof EmailOptionsSchema> = {
 			},
 		}));
 	},
-	getNodeBindings(_options) {
-		return {};
+	getNodeBindings(options) {
+		if (!options.email?.send_email) {
+			return {};
+		}
+
+		return Object.fromEntries(
+			options.email.send_email.map(({ name }) => [name, new ProxyNodeBinding()])
+		);
 	},
 	async getServices(args) {
-		const services: Service[] = [];
+		if (!args.options.email?.send_email) {
+			return [];
+		}
+
+		const emailDirectory = path.join(args.tmpPath, EMAIL_PLUGIN_NAME);
+		await mkdir(emailDirectory, { recursive: true });
+
+		const services: Service[] = [
+			{
+				name: EMAIL_DISK_SERVICE_NAME,
+				disk: {
+					path: emailDirectory,
+					writable: true,
+				},
+			},
+		];
 
 		for (const { name, remoteProxyConnectionString, ...config } of args.options
 			.email?.send_email ?? []) {
@@ -90,7 +115,14 @@ export const EMAIL_PLUGIN: Plugin<typeof EmailOptionsSchema> = {
 							],
 							bindings: [
 								...buildJsonBindings(config),
-								WORKER_BINDING_SERVICE_LOOPBACK,
+								{
+									name: EMAIL_DISK_BINDING_NAME,
+									service: { name: EMAIL_DISK_SERVICE_NAME },
+								},
+								{
+									name: "email_directory",
+									json: JSON.stringify(emailDirectory),
+								},
 							],
 						},
 			});

packages/miniflare/src/workers/email/send_email.worker.ts

@@ -1,8 +1,6 @@
 import { WorkerEntrypoint } from "cloudflare:workers";
 import { blue } from "kleur/colors";
-import { LogLevel, SharedHeaders } from "miniflare:shared";
 import PostalMime from "postal-mime";
-import { CoreBindings } from "../core/constants";
 import { RAW_EMAIL } from "./constants";
 import { type MiniflareEmailMessage as EmailMessage } from "./email.worker";
 import type { EmailAddress, MessageBuilder } from "./types";
@@ -66,31 +64,33 @@ function formatMessageBuilder(builder: MessageBuilder): string {
 	return lines.join("\n");
 }
 
+/**
+ * Appends path segments to a base path using the separator already implied by
+ * the base path string. This trims trailing `/` and `\` from the base before
+ * joining, but does not otherwise normalize the full path.
+ */
+function joinPath(base: string, ...segments: string[]): string {
+	const separator = base.includes("\\") ? "\\" : "/";
+	return [base.replace(/[\\/]+$/, ""), ...segments].join(separator);
+}
+
 interface SendEmailEnv {
-	[CoreBindings.SERVICE_LOOPBACK]: Fetcher;
+	MINIFLARE_EMAIL_DISK: Fetcher;
+	email_directory: string;
 	destination_address: string | undefined;
 	allowed_destination_addresses: string[] | undefined;
 	allowed_sender_addresses: string[] | undefined;
 }
 
 export class SendEmailBinding extends WorkerEntrypoint<SendEmailEnv> {
 	/**
-	 * Logs a message via the loopback service
+	 * Logs a message via the runtime console.
 	 */
-	private log(message: string, level: LogLevel = LogLevel.INFO): void {
-		this.ctx.waitUntil(
-			this.env[CoreBindings.SERVICE_LOOPBACK].fetch(
-				"http://localhost/core/log",
-				{
-					method: "POST",
-					headers: { [SharedHeaders.LOG_LEVEL]: level.toString() },
-					body: message,
-				}
-			)
-		);
+	private log(message: string): void {
+		console.log(message);
 	}
 	/**
-	 * Stores content to a temporary file via the loopback service
+	 * Stores content to a temporary file via the disk service.
 	 */
 	private async storeTempFile(
 		content: string | ArrayBuffer | ArrayBufferView,
@@ -111,14 +111,14 @@ export class SendEmailBinding extends WorkerEntrypoint<SendEmailEnv> {
 			);
 		}
 
-		const resp = await this.env[CoreBindings.SERVICE_LOOPBACK].fetch(
-			`http://localhost/core/store-temp-file?extension=${extension}&prefix=${prefix}`,
-			{
-				method: "POST",
-				body,
-			}
-		);
-		return await resp.text();
+		const fileName = `${crypto.randomUUID()}.${extension}`;
+		const url = new URL(`${prefix}/${fileName}`, "http://placeholder/");
+		await this.env.MINIFLARE_EMAIL_DISK.fetch(url, {
+			method: "PUT",
+			body,
+		});
+
+		return joinPath(this.env.email_directory, prefix, fileName);
 	}
 
 	private checkDestinationAllowed(to: string) {