fetchWithProxy.ts

import { Proxy } from "../types";
import * as undici from "undici";

export const fetchWithProxy = (
  proxy: Proxy | undefined | null,
  url: string,
  opts: Parameters<typeof fetch>[1]
): Promise<Response> => {
  if (!proxy) {
    return fetch(url, opts);
  }

  let proxyStr = `${proxy.username}:${proxy.password}@${proxy.host}:${proxy.port}`;

  const prefix =
    proxy.type === "HTTPS"
      ? "https://"
      : proxy.type === "HTTP"
      ? "http://"
      : "socks5://";

  if (globalThis.Bun !== undefined) {
    return fetch(url, {
      ...opts,
      proxy: `${prefix}${proxyStr}`,
    } as any);
  }

  const agent = new undici.ProxyAgent({
    uri: `${prefix}${proxyStr}`,
    token: `Basic ${Buffer.from(`${proxy.username}:${proxy.password}`).toString(
      "base64"
    )}`,
  });

  return undici.fetch(url, {
    ...opts,
    dispatcher: agent,
  } as any) as any;
};