SMTP: extend env parsing (domain/auth/starttls); add unit test with mocked TLS for sendSmtpMail; extend SmtpConfig; docs to set .env locally

src/lib/env.ts

@@ -8,8 +8,11 @@ const envSchema = z.object({
   NEXT_PUBLIC_APP_URL: z.string().url().optional(),
   SMTP_ADDRESS: z.string().optional(),
   SMTP_PORT: z.coerce.number().optional(),
+  SMTP_DOMAIN: z.string().optional(),
   SMTP_USERNAME: z.string().optional(),
   SMTP_PASSWORD: z.string().optional(),
+  SMTP_AUTHENTICATION: z.string().optional(),
+  SMTP_ENABLE_STARTTLS_AUTO: z.string().optional(),
   SMTP_TLS: z.string().optional(),
   MAILER_SENDER_EMAIL: z.string().optional(),
 })
@@ -31,9 +34,12 @@ export const env = {
     ? {
         host: parsed.data.SMTP_ADDRESS,
         port: parsed.data.SMTP_PORT ?? 465,
+        domain: parsed.data.SMTP_DOMAIN,
         username: parsed.data.SMTP_USERNAME,
         password: parsed.data.SMTP_PASSWORD,
         tls: (parsed.data.SMTP_TLS ?? "true").toLowerCase() === "true",
+        starttls: (parsed.data.SMTP_ENABLE_STARTTLS_AUTO ?? "false").toLowerCase() === "true",
+        auth: parsed.data.SMTP_AUTHENTICATION ?? "login",
         from: parsed.data.MAILER_SENDER_EMAIL ?? "no-reply@example.com",
       }
     : null,

src/server/email-smtp.ts

@@ -6,6 +6,7 @@ type SmtpConfig = {
   username: string
   password: string
   from: string
+  tls?: boolean
 }
 
 function b64(input: string) {
@@ -66,4 +67,3 @@ export async function sendSmtpMail(cfg: SmtpConfig, to: string, subject: string,
     socket.on("error", reject)
   })
 }
-

tests/email-smtp.test.ts

@@ -0,0 +1,91 @@
+import { describe, it, expect, vi, beforeEach } from "vitest"
+
+// Mock tls to simulate an SMTP server over implicit TLS
+vi.mock("tls", () => {
+  class MockSocket {
+    listeners: Record<string, Function[]> = {}
+    writes: string[] = []
+    // very small state machine of server responses
+    private step = 0
+    on(event: string, cb: Function) {
+      this.listeners[event] = this.listeners[event] || []
+      this.listeners[event].push(cb)
+      return this
+    }
+    removeListener(event: string, cb: Function) {
+      if (!this.listeners[event]) return this
+      this.listeners[event] = this.listeners[event].filter((f) => f !== cb)
+      return this
+    }
+    emit(event: string, data?: unknown) {
+      for (const cb of this.listeners[event] || []) cb(data)
+    }
+    write(chunk: string) {
+      this.writes.push(chunk)
+      const line = chunk.replace(/\r?\n/g, "")
+      // Respond depending on client command
+      if (this.step === 0 && line.startsWith("EHLO")) {
+        this.step = 1
+        this.emit("data", Buffer.from("250-local\r\n"))
+        this.emit("data", Buffer.from("250 OK\r\n"))
+      } else if (this.step === 1 && line === "AUTH LOGIN") {
+        this.step = 2
+        this.emit("data", Buffer.from("334 VXNlcm5hbWU6\r\n"))
+      } else if (this.step === 2) {
+        this.step = 3
+        this.emit("data", Buffer.from("334 UGFzc3dvcmQ6\r\n"))
+      } else if (this.step === 3) {
+        this.step = 4
+        this.emit("data", Buffer.from("235 Auth OK\r\n"))
+      } else if (this.step === 4 && line.startsWith("MAIL FROM:")) {
+        this.step = 5
+        this.emit("data", Buffer.from("250 FROM OK\r\n"))
+      } else if (this.step === 5 && line.startsWith("RCPT TO:")) {
+        this.step = 6
+        this.emit("data", Buffer.from("250 RCPT OK\r\n"))
+      } else if (this.step === 6 && line === "DATA") {
+        this.step = 7
+        this.emit("data", Buffer.from("354 End data with <CR><LF>.<CR><LF>\r\n"))
+      } else if (this.step === 7 && line.endsWith(".")) {
+        this.step = 8
+        this.emit("data", Buffer.from("250 Queued\r\n"))
+      } else if (this.step === 8 && line === "QUIT") {
+        this.emit("end")
+      }
+    }
+    end() {}
+  }
+
+  function connect(_port: number, _host: string, _opts: unknown, cb?: Function) {
+    const socket = new MockSocket()
+    // initial server greeting
+    setTimeout(() => {
+      cb?.()
+      socket.emit("data", Buffer.from("220 Mock SMTP Ready\r\n"))
+    }, 0)
+    return socket as unknown as NodeJS.WritableStream & { on: MockSocket["on"] }
+  }
+
+  return { default: { connect }, connect }
+})
+
+describe("sendSmtpMail", () => {
+  it("performs AUTH LOGIN and sends a message", async () => {
+    const { sendSmtpMail } = await import("@/server/email-smtp")
+    await expect(
+      sendSmtpMail(
+        {
+          host: "smtp.mock",
+          port: 465,
+          username: "user@example.com",
+          password: "secret",
+          from: "Sender <sender@example.com>",
+        },
+        "rcpt@example.com",
+        "Subject here",
+        "<p>Hello</p>"
+      )
+    ).resolves.toBeUndefined()
+  })
+})
+