ddg-chatai.ts

import { TextLineStream } from "https://deno.land/std@0.223.0/streams/text_line_stream.ts";
import * as bufio from "https://deno.land/std@0.101.0/io/bufio.ts";

type AiModel = "gpt-3.5-turbo-0125" | "claude-instant-1.2";

export async function isStatusOK(): Promise<boolean> {
  return await fetch("https://duckduckgo.com/duckchat/v1/status")
    .then((response) => response.json()).then((data) =>
      parseInt(data["status"]) === 0
    );
}

async function fetchChatResponseStream(
  prompt: string,
  model: AiModel,
  vqd4: string,
): Promise<ReadableStream<string>> {
  const payload = {
    "model": model,
    "messages": [{ "role": "user", "content": prompt }],
  };

  const headers = {
    "User-Agent":
      "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/118.0.0.0 Safari/537.36",
    "Accept": "text/event-stream",
    "Accept-Language": "ja,en-US;q=0.7,en;q=0.3",
    "Content-Type": "application/json",
    "Sec-Fetch-Dest": "empty",
    "Sec-Fetch-Mode": "cors",
    "Sec-Fetch-Site": "same-origin",
    "Sec-GPC": "1",
    "sec-ch-ua-platform": '"Windows"',
    "sec-ch-ua":
      '"Google Chrome";v="118", "Chromium";v="118", "Not=A?Brand";v="24"',
    "sec-ch-ua-mobile": "?0",
    "Pragma": "no-cache",
    "Cache-Control": "no-cache",
    "x-vqd-4": vqd4,
  };

  return await fetch("https://duckduckgo.com/duckchat/v1/chat", {
    "method": "POST",
    "credentials": "include",
    "headers": headers,
    "referrer": "https://duckduckgo.com/",
    "mode": "cors",
    "body": JSON.stringify(payload),
  }).then((response: Response) => {
    const stream = response.body!
      .pipeThrough(new TextDecoderStream())
      .pipeThrough(new TextLineStream());

    return stream;
  });
}

async function printChatResponse(
  reader: ReadableStreamDefaultReader<string>,
) {
  const buf = bufio.BufWriter.create(Deno.stdout);
  const encoder = new TextEncoder();

  while (true) {
    const result: ReadableStreamDefaultReadResult<string> = await reader.read();
    const line: string = result.value?.replace("data: ", "")!;

    if (result.done || line.startsWith("[DONE]")) {
      break;
    }

    console.debug(line);

    //const json = JSON.parse(line);
    //console.debug(json);
    //buf.write(encoder.encode(json["message"]));
    buf.write(encoder.encode(" "));
  }

  await buf.flush();
}