From 009d37f496cb3963f169b7454644cf04bee01d90 Mon Sep 17 00:00:00 2001
From: mathe42 <2pi_r2@gmx.de>
Date: Thu, 21 Apr 2022 19:16:01 +0200
Subject: [PATCH] feat: add Worker and Worker Pool (unstable)

---
 README.md |   5 +++
 mod.ts    |   1 +
 pool.ts   | 107 ++++++++++++++++++++++++++++++++++++++++++++++++++++++
 worker.ts |  40 ++++++++++++++++++++
 4 files changed, 153 insertions(+)
 create mode 100644 pool.ts
 create mode 100644 worker.ts

diff --git a/README.md b/README.md
index 529800c..61d168a 100644
--- a/README.md
+++ b/README.md
@@ -156,6 +156,11 @@ const client = new SmtpClient({
 });
 ```
 
+## Pool, Worker
+> This is unstable API may change! This requires deno to run in unstable mode.
+
+Adds 2 new classes `SMTPWorker` and `SMTPWorkerPool` (for constructor options see code for now). This creates a SMTP client (or multiple) that get automaticly killed if the connection is not used for around 60s.
+
 ## TLS issues
 When getting TLS errors make shure:
 1. you use the correct port (mostly 25, 587, 465)
diff --git a/mod.ts b/mod.ts
index 34671a9..4e6d8c9 100644
--- a/mod.ts
+++ b/mod.ts
@@ -5,3 +5,4 @@ export type {
 } from "./config.ts";
 export { SmtpClient } from "./smtp.ts";
 export { quotedPrintableEncode } from "./encoding.ts";
+export { SMTPWorker, SMTPWorkerPool } from './pool.ts'
\ No newline at end of file
diff --git a/pool.ts b/pool.ts
new file mode 100644
index 0000000..d281167
--- /dev/null
+++ b/pool.ts
@@ -0,0 +1,107 @@
+import { ConnectConfigWithAuthentication, SendConfig } from "./config.ts";
+
+export class SMTPWorker {
+  #timeout: number;
+
+  constructor(
+    config: ConnectConfigWithAuthentication,
+    { timeout = 60000, autoconnect = true } = {},
+  ) {
+    this.#config = config;
+    this.#timeout = timeout;
+    if(autoconnect) {
+      this.#startup();
+    }
+  }
+  #w!: Worker;
+  #idleTO: number | null = null;
+  #idleMode2 = false;
+  #noCon = true;
+  #config: ConnectConfigWithAuthentication;
+
+  #startup() {
+    this.#w = new Worker(new URL("./worker.ts", import.meta.url), {
+      type: "module",
+      deno: {
+        permissions: {
+          net: "inherit",
+          // ts files
+          read: true,
+        },
+        namespace: true,
+      },
+    });
+
+    this.#w.addEventListener("message", (ev: MessageEvent<boolean>) => {
+      if (ev.data) {
+        this.#stopIdle();
+      } else {
+        if (this.#idleMode2) {
+          this.#cleanup();
+        } else {
+          this.#startIdle();
+        }
+      }
+    });
+
+    this.#w.postMessage({
+      __setup: this.#config,
+    });
+
+    this.#noCon = false;
+  }
+
+  #startIdle() {
+    console.log("started idle");
+    if (this.#idleTO) return;
+
+    this.#idleTO = setTimeout(() => {
+      console.log("idle mod 2");
+      this.#idleMode2 = true;
+      this.#w.postMessage({ __check_idle: true });
+    }, this.#timeout);
+  }
+
+  #stopIdle() {
+    if (this.#idleTO) clearTimeout(this.#idleTO);
+
+    this.#idleMode2 = false;
+    this.#idleTO = null;
+  }
+
+  #cleanup() {
+    console.log("killed");
+    this.#w.terminate();
+    this.#stopIdle();
+  }
+
+  public send(mail: SendConfig) {
+    this.#stopIdle();
+    if (this.#noCon) {
+      this.#startup();
+    }
+    this.#w.postMessage(mail);
+  }
+}
+
+export class SMTPWorkerPool {
+  pool: SMTPWorker[] = []
+
+  constructor(
+    config: ConnectConfigWithAuthentication,
+    { timeout = 60000, size = 2 } = {}
+  ) {
+    for (let i = 0; i < size; i++) {
+      this.pool.push(new SMTPWorker(config, {timeout, autoconnect: i === 0}))
+    }
+  }
+
+  #lastUsed = -1
+
+  send(mail: SendConfig) {
+    this.#lastUsed = (this.#lastUsed + 1) % this.pool.length
+
+    this.pool[this.#lastUsed].send(mail)
+  }
+}
+
diff --git a/worker.ts b/worker.ts
new file mode 100644
index 0000000..00abb78
--- /dev/null
+++ b/worker.ts
@@ -0,0 +1,40 @@
+/// <reference no-default-lib="true" />
+/// <reference lib="deno.worker" />
+/// <reference lib="deno.unstable" />
+
+import { SmtpClient } from "./smtp.ts";
+import { SendConfig } from "./config.ts";
+
+const client = new SmtpClient({ console_debug: true });
+
+let cb: () => void;
+const readyPromise = new Promise<void>((res) => {
+  cb = res;
+});
+
+let hasIdlePromise = false;
+
+async function send(config: SendConfig) {
+  client.send(config);
+
+  if (!hasIdlePromise) {
+    hasIdlePromise = true;
+    await client.idle;
+    postMessage(false);
+    hasIdlePromise = false;
+  }
+}
+
+addEventListener("message", async (ev: MessageEvent) => {
+  if (ev.data.__setup) {
+    await client.connectTLS(ev.data.__setup);
+    cb();
+    return;
+  }
+  if (ev.data.__check_idle) {
+    postMessage(client.isSending);
+    return;
+  }
+  await readyPromise;
+  send(ev.data);
+});