.

package.json

@@ -18,6 +18,7 @@
     "@types/mailparser": "^2.7.0",
     "@types/node": "^13.9.1",
     "@types/node-fetch": "^2.5.5",
+    "@types/nodemailer": "^6.4.0",
     "@types/react": "^16.9.23",
     "@types/react-dom": "^16.9.5",
     "@types/smtp-server": "^3.5.3",
@@ -25,6 +26,7 @@
     "concurrently": "^5.1.0",
     "jest": "^25.1.0",
     "node-fetch": "^2.6.0",
+    "nodemailer": "^6.4.5",
     "nodemon": "^2.0.2",
     "prettier": "^1.19.1",
     "typescript": "^3.8.3"

src/index.tsx

@@ -33,6 +33,7 @@ const webApp = express()
   });
 
 export const emailServer = new SMTPServer({
+  authOptional: true,
   async onData(stream, session, callback) {
     const paths = session.envelope.rcptTo.flatMap(({ address }) => {
       const match = address.match(/^(\w+)@kill-the-newsletter.com$/);
@@ -44,7 +45,7 @@ export const emailServer = new SMTPServer({
     });
     if (paths.length === 0) return callback();
     const email = await simpleParser(stream);
-    const entry = Entry({
+    const { entry } = Entry({
       title: email.subject,
       author: email.from.text,
       content: typeof email.html !== "boolean" ? email.html : email.textAsHtml
@@ -54,8 +55,10 @@ export const emailServer = new SMTPServer({
         fs.readFileSync(path).toString()
       );
       xml.feed.updated = now();
+      if (xml.feed.entry === undefined) xml.feed.entry = [];
       xml.feed.entry.unshift(entry);
-      while (renderXML(xml).length > 500_000) xml.feed.entry.pop();
+      while (xml.feed.entry.length > 0 && renderXML(xml).length > 500_000)
+        xml.feed.entry.pop();
       fs.writeFileSync(path, renderXML(xml));
     }
     callback();
@@ -275,7 +278,7 @@ function feedURL(token: string) {
   return `https://www.kill-the-newsletter.com/feeds/${token}.xml`;
 }
 
-function feedEmail(token: string) {
+export function feedEmail(token: string) {
   return `${token}@kill-the-newsletter.com`;
 }
 

src/test.ts

@@ -1,17 +1,61 @@
-import { developmentWebServer, emailServer, feedPath } from ".";
+import { developmentWebServer, emailServer, feedPath, feedEmail } from ".";
+import { createTransport } from "nodemailer";
 import fetch from "node-fetch";
 import fs from "fs";
 
 test("create feed", async () => {
   const token = await createFeed();
-  const feed = fs.readFileSync(feedPath(token)).toString();
 
-  expect(feed).toMatch("My Feed");
+  expect(readFeed(token)).toMatch("My Feed");
 });
 
-test("receive email", async () => {
+describe("receive email", () => {
+  const transporter = createTransport({
+    host: "localhost",
+    port: 2525,
+    tls: { rejectUnauthorized: false }
+  });
+
+  test("HTML content", async () => {
     const token = await createFeed();
-})
+    await transporter.sendMail({
+      from: "publisher@example.com",
+      to: feedEmail(token),
+      subject: "New Message",
+      html: "<p>HTML content</p>"
+    });
+    const feed = readFeed(token);
+    expect(feed).toMatch("publisher@example.com");
+    expect(feed).toMatch("New Message");
+    expect(feed).toMatch("HTML content");
+  });
+
+  test("text content", async () => {
+    const token = await createFeed();
+    await transporter.sendMail({
+      from: "publisher@example.com",
+      to: feedEmail(token),
+      subject: "New Message",
+      text: "TEXT content"
+    });
+    const feed = readFeed(token);
+    expect(feed).toMatch("TEXT content");
+  });
+
+  test("truncation", async () => {
+    const token = await createFeed();
+    for (const repetition of [...new Array(4).keys()])
+      await transporter.sendMail({
+        from: "publisher@example.com",
+        to: feedEmail(token),
+        subject: "New Message",
+        text: `REPETITION ${repetition} `.repeat(10_000)
+      });
+    const feed = readFeed(token);
+    expect(feed).toMatch("REPETITION 3");
+    expect(feed).not.toMatch("REPETITION 0");
+  }, 10_000);
+});
 
 afterAll(() => {
   developmentWebServer.close();
@@ -26,3 +70,7 @@ async function createFeed(): Promise<string> {
   const responseText = await response.text();
   return responseText.match(/(\w{20}).xml/)![1];
 }
+
+function readFeed(token: string): string {
+  return fs.readFileSync(feedPath(token)).toString();
+}