protohackers/5.ts

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2022-10-21 15:25:46 -05:00
import { BufReader } from "https://deno.land/std@0.157.0/io/buffer.ts";
import { copy } from "https://deno.land/std@0.156.0/streams/conversion.ts";
const PORT = 5588;
const PROXY_CHAT_SERVER = "chat.protohackers.com";
const PROXY_CHAT_PORT = 16963;
const TONYS_ADDRESS = "7YWHMfk9JZe0LM0g1ZauHuiSxhI";
const tEnc = new TextEncoder();
console.log(`Starting TCP listener on on 0.0.0.0:${PORT}`);
async function chatSession(conn: Deno.Conn) {
const proxy = await Deno.connect({
hostname: PROXY_CHAT_SERVER,
port: PROXY_CHAT_PORT,
});
const closeOnDisconnect = () => {
console.warn("Disconnected client");
try {
proxy.close();
} catch (err) {
console.error("Error closing proxy connection:", err);
}
try {
conn.close();
} catch (err) {
console.error("Error closing client connection:", err);
}
};
rewriteMessages(conn, proxy).catch((e) => e).finally(closeOnDisconnect);
rewriteMessages(proxy, conn).catch((e) => e).finally(closeOnDisconnect);
}
const chatCommands = (reader: Deno.Conn) => ({
async *[Symbol.asyncIterator]() {
let s = await BufReader.create(reader).readString("\n");
if (!s) return;
while (s) {
console.log(s);
yield s;
s = await BufReader.create(reader).readString("\n");
}
},
});
async function rewriteMessages(reader: Deno.Conn, writer: Deno.Conn) {
try {
for await (const rawLine of chatCommands(reader)) {
if (!rawLine || !rawLine.endsWith("\n")) throw "incomplete chat command";
const line = rawLine.trim();
console.debug("Line:", line);
await writer.write(tEnc.encode(replaceAddresses(line) + "\n"));
}
} catch (err) {
console.error("Error reading line:", err, { ...err });
throw err;
}
}
function replaceAddresses(text: string): string {
const result = text.split(" ").map((word) => replaceAddress(word)).join(" ");
if (result != text) console.debug("replaced text:", result);
return result;
}
function replaceAddress(word: string): string {
const result = word.replace(
/^7\w{25,34}$/i,
TONYS_ADDRESS,
);
if (word != result) console.debug("word:", word, "replaced:", result);
return result;
}
for await (const conn of Deno.listen({ port: PORT })) {
console.log("Connection established:", conn.remoteAddr);
chatSession(conn);
console.log("Connection closed:", conn.remoteAddr);
}