strfry-policies/src/policies/anti-duplication-policy.ts
2023-03-24 13:06:56 -05:00

73 lines
1.8 KiB
TypeScript
Executable File

#!/bin/sh
//bin/true; exec deno run -A "$0" "$@"
import { readLines } from 'https://deno.land/std@0.178.0/io/mod.ts';
import { Keydb } from 'https://deno.land/x/keydb@1.0.0/sqlite.ts';
const ANTI_DUPLICATION_TTL = Number(Deno.env.get('ANTI_DUPLICATION_TTL') || 60000);
const ANTI_DUPLICATION_MIN_LENGTH = Number(Deno.env.get('ANTI_DUPLICATION_MIN_LENGTH') || 50);
interface InputMessage {
type: 'new' | 'lookback';
event: Event;
receivedAt: number;
sourceType: 'IP4' | 'IP6' | 'Import' | 'Stream' | 'Sync';
sourceInfo: string;
}
interface OutputMessage {
id: string;
action: 'accept' | 'reject' | 'shadowReject';
msg: string;
}
interface Event {
id: string;
sig: string;
kind: number;
tags: string[][];
pubkey: string;
content: string;
created_at: number;
}
/** https://stackoverflow.com/a/8831937 */
function hashCode(str: string): number {
let hash = 0;
for (let i = 0, len = str.length; i < len; i++) {
const chr = str.charCodeAt(i);
hash = (hash << 5) - hash + chr;
hash |= 0; // Convert to 32bit integer
}
return hash;
}
async function handleMessage(msg: InputMessage): Promise<OutputMessage> {
const { kind, content } = msg.event;
if (kind === 1 && content.length >= ANTI_DUPLICATION_MIN_LENGTH) {
const db = new Keydb('sqlite:///tmp/strfry-anti-duplication-policy.sqlite3');
const hash = String(hashCode(content));
if (await db.get(hash)) {
await db.set(hash, 1, ANTI_DUPLICATION_TTL);
return {
id: msg.event.id,
action: 'shadowReject',
msg: '',
};
}
await db.set(hash, 1, ANTI_DUPLICATION_TTL);
}
return {
id: msg.event.id,
action: 'accept',
msg: '',
};
}
for await (const line of readLines(Deno.stdin)) {
console.log(JSON.stringify(await handleMessage(JSON.parse(line))));
}