Implement optional flood protection (#11)

* Implement optional flood protection

* Resolve formatting error

* Move to plugin architecture

* Clean up old changes

* Add test for antiflood

* Add negative test case

* Fix missing await on standard send

* Make floodDelay check explicit and bound to positive values

* Use const in antiflood_test.ts

* Fix formatting error

* Add guard on no or invalid floodDelay to skip antiflood plugin

Author: aronson

API.md

@@ -5,6 +5,7 @@
   - [option: bufferSize](#option-buffersize)
   - [option: channels](#option-channels)
   - [option: ctcpReplies](#option-ctcpreplies)
+  - [option: floodDelay](#option-flooddelay)
   - [option: joinOnInvite](#option-joinoninvite)
   - [option: maxListeners](#option-maxlisteners)
   - [option: nick](#option-nick)
@@ -238,6 +239,18 @@ const client = new Client({
 });
 ```
 
+### option: floodDelay
+
+Milliseconds to wait between dispatching private messages.
+
+Defaults to 0 milliseconds (no delay).
+
+```ts
+const client = new Client({
+  floodDelay: 2000,
+});
+```
+
 ### option: joinOnInvite
 
 Enables auto join on invite.

client.ts

@@ -4,6 +4,7 @@ import { CoreClient, type CoreFeatures } from "./core/client.ts";
 import { type CombinePluginFeatures } from "./core/plugins.ts";
 
 import action from "./plugins/action.ts";
+import antiflood from "./plugins/antiflood.ts";
 import away from "./plugins/away.ts";
 import cap from "./plugins/cap.ts";
 import chanmodes from "./plugins/chanmodes.ts";
@@ -48,6 +49,7 @@ import whois from "./plugins/whois.ts";
 
 const plugins = [
   action,
+  antiflood,
   away,
   cap,
   chanmodes,

deps.ts

@@ -12,3 +12,5 @@ export { assertExists } from "https://deno.land/[email protected]/assert/assert_exists
 export { assertMatch } from "https://deno.land/[email protected]/assert/assert_match.ts";
 export { assertRejects } from "https://deno.land/[email protected]/assert/assert_rejects.ts";
 export { assertThrows } from "https://deno.land/[email protected]/assert/assert_throws.ts";
+
+export { Queue } from "https://deno.land/x/[email protected]/mod.ts";

plugins/antiflood.ts

@@ -0,0 +1,36 @@
+import { createPlugin } from "../core/plugins.ts";
+import { Queue } from "../deps.ts";
+
+interface AntiFloodFeatures {
+  options: {
+    /** Milliseconds to wait between dispatching private messages.
+     *
+     * Defaults to 0 milliseconds (no delay) */
+    floodDelay?: number;
+  };
+}
+
+export default createPlugin("antiflood", [])<AntiFloodFeatures>(
+  (client, options) => {
+    if (!options.floodDelay || options.floodDelay <= 0) return;
+    // Queue object and delay structure for anti-flood protection
+    const queue = new Queue();
+    const delay = (ms = 0) => new Promise((resolve) => setTimeout(resolve, ms));
+
+    // Queues up limiter for outgoing messages with before and after send hooks
+
+    client.hooks.hookCall("send", async (send, command, ...params) => {
+      if (command === "PRIVMSG") {
+        return queue.push(async () => {
+          const raw = await send(command, ...params);
+          if (raw) {
+            await delay(options.floodDelay);
+          }
+          return raw;
+        });
+      } else {
+        return await send(command, ...params);
+      }
+    });
+  },
+);

plugins/antiflood_test.ts

@@ -0,0 +1,43 @@
+import { assertEquals } from "../deps.ts";
+import { delay, describe } from "../testing/helpers.ts";
+import { mock } from "../testing/mock.ts";
+
+describe("plugins/antiflood", (test) => {
+  test("send two PRIVMSG with delay", async () => {
+    const { client, server } = await mock({ floodDelay: 250 });
+
+    client.privmsg("#channel", "Hello world");
+    client.privmsg("#channel", "Hello world, again");
+    let raw = server.receive();
+
+    // Should only get first message
+    assertEquals(raw, [
+      "PRIVMSG #channel :Hello world",
+    ]);
+
+    // Wait for second message to make it through
+    await delay(1000);
+    raw = server.receive();
+
+    // Second message now dispatched to server
+    assertEquals(raw, [
+      "PRIVMSG #channel :Hello world, again",
+    ]);
+  });
+});
+
+describe("plugins/antiflood", (test) => {
+  test("disabled when delay not set", async () => {
+    const { client, server } = await mock();
+
+    client.privmsg("#channel", "Hello world");
+    client.privmsg("#channel", "Hello world, again");
+    const raw = server.receive();
+
+    // Should get both messages
+    assertEquals(raw, [
+      "PRIVMSG #channel :Hello world",
+      "PRIVMSG #channel :Hello world, again",
+    ]);
+  });
+});

testing/helpers.ts

@@ -9,3 +9,7 @@ export function describe(name: string, fn: (test: Test) => void): void {
 function prettify(describeName: string, testName: string) {
   return bold(describeName) + dim(" > ") + testName;
 }
+
+export function delay(ms = 0) {
+  return new Promise((resolve) => setTimeout(resolve, ms));
+}