fix: auto-reply not triggering when source_prefix is empty (#880)

* fix: auto-reply not triggering when source_prefix is empty (#459)

- Empty source_prefix now matches all senders (was short-circuiting as falsy)
- Support regex matching with /pattern/ syntax in source_prefix
- Backward compatible: plain strings still use startsWith
- Use E2E_TEST_MODE switch to skip cloudflare:email import in tests
- Track reply() calls in E2E mock for testability

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

* feat: update auto-reply UI labels for regex support

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

* docs: update changelogs for auto-reply fix and regex feature

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

* feat: upgrade version to v1.5.0

- Update version number to 1.5.0 in all package.json files and constants.ts
- Split CHANGELOG: v1.4.0 entries finalized, new v1.5.0(main) section with auto-reply changes

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

* fix: add error logging for invalid regex in auto-reply source_prefix

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

* refactor: address CodeRabbit review suggestions

- Use const object instead of let for mock state tracking
- Add log when auto-reply subject/message falls back to defaults

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

* docs: add source_prefix regex syntax to auto-reply docs

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

---------

Co-authored-by: Claude Opus 4.6 <noreply@anthropic.com>

worker/package.json

@@ -1,6 +1,6 @@
 {
   "name": "cloudflare_temp_email",
-  "version": "1.4.0",
+  "version": "1.5.0",
   "private": true,
   "type": "module",
   "scripts": {

worker/src/admin_api/e2e_test_api.ts

@@ -44,20 +44,19 @@ const receiveMail = async (c: Context<HonoCustomType>) => {
     if (!headers.has('Message-ID')) headers.set('Message-ID', `<e2e-${Date.now()}@test>`);
 
     const rawBytes = new TextEncoder().encode(raw);
-    let rejected: string | undefined;
+    const state = { rejected: undefined as string | undefined, replyCalled: false };
     const mockMessage: ForwardableEmailMessage = {
         from, to, headers,
         rawSize: rawBytes.byteLength,
         raw: new ReadableStream({ start(ctrl) { ctrl.enqueue(rawBytes); ctrl.close(); } }),
-        setReject(reason: string) { rejected = reason; },
+        setReject(reason: string) { state.rejected = reason; },
         forward: async () => ({ messageId: '' }),
-        reply: async () => ({ messageId: '' }),
+        reply: async () => { state.replyCalled = true; return { messageId: '' }; },
     };
-
     const { email: emailHandler } = await import('../email');
     await emailHandler(mockMessage, c.env, { waitUntil: () => {}, passThroughOnException: () => {} });
 
-    return c.json({ success: !rejected, ...(rejected ? { rejected } : {}) });
+    return c.json({ success: !state.rejected, replyCalled: state.replyCalled, ...(state.rejected ? { rejected: state.rejected } : {}) });
 };
 
 export default { seedMail, receiveMail };

worker/src/constants.ts

@@ -1,5 +1,5 @@
 export const CONSTANTS = {
-    VERSION: 'v' + '1.4.0',
+    VERSION: 'v' + '1.5.0',
 
     // DB Version
     DB_VERSION_KEY: 'db_version',

worker/src/email/auto_reply.ts

@@ -1,6 +1,26 @@
 import { createMimeMessage } from "mimetext";
 import { getBooleanValue } from "../utils";
 
+/**
+ * Check if the sender matches the source_prefix filter.
+ * - empty/undefined: match all senders
+ * - starts and ends with `/`: treat as regex (e.g. `/.*@example\.com$/`)
+ * - otherwise: legacy startsWith match
+ */
+function matchSender(from: string, sourcePrefix: string | undefined): boolean {
+    if (!sourcePrefix) return true;
+    if (sourcePrefix.startsWith("/") && sourcePrefix.endsWith("/") && sourcePrefix.length > 2) {
+        try {
+            const regex = new RegExp(sourcePrefix.slice(1, -1));
+            return regex.test(from);
+        } catch (error) {
+            console.error("Invalid regex in source_prefix:", sourcePrefix, error);
+            return false;
+        }
+    }
+    return from.startsWith(sourcePrefix);
+}
+
 export const auto_reply = async (message: ForwardableEmailMessage, env: Bindings): Promise<void> => {
     const message_id = message.headers.get("Message-ID");
     // auto reply email
@@ -9,7 +29,10 @@ export const auto_reply = async (message: ForwardableEmailMessage, env: Bindings
             const results = await env.DB.prepare(
                 `SELECT * FROM auto_reply_mails where address = ? and enabled = 1`
             ).bind(message.to).first<Record<string, string>>();
-            if (results && results.source_prefix && message.from.startsWith(results.source_prefix)) {
+            if (results && matchSender(message.from, results.source_prefix)) {
+                if (!results.subject || !results.message) {
+                    console.log("auto-reply using defaults:", !results.subject ? "subject" : "", !results.message ? "message" : "");
+                }
                 const msg = createMimeMessage();
                 msg.setHeader("In-Reply-To", message_id);
                 msg.setSender({
@@ -22,14 +45,18 @@ export const auto_reply = async (message: ForwardableEmailMessage, env: Bindings
                     contentType: 'text/plain',
                     data: results.message || "This is an auto-reply message, please reconact later."
                 });
-                const { EmailMessage } = await import('cloudflare:email');
-                const replyMessage = new EmailMessage(
-                    message.to,
-                    message.from,
-                    msg.asRaw()
-                );
-                // @ts-ignore
-                await message.reply(replyMessage);
+                if (getBooleanValue(env.E2E_TEST_MODE)) {
+                    await message.reply(msg.asRaw());
+                } else {
+                    const { EmailMessage } = await import('cloudflare:email');
+                    const replyMessage = new EmailMessage(
+                        message.to,
+                        message.from,
+                        msg.asRaw()
+                    );
+                    // @ts-ignore
+                    await message.reply(replyMessage);
+                }
             }
         } catch (error) {
             console.log("reply email error", error);