Upload & download

import { setTimeout as delay } from "node:timers/promises";
import { open } from "node:fs/promises";
import { chromium } from "playwright";
import { TabSail } from "tabsail";

const client = new TabSail();

await client.withSession({ timeoutSeconds: 300 }, async (session) => {
  if (!session.downloadDirectory) throw new Error("Browser is not ready");
  const grant = await client.sessions.connections.create(session.id, { type: "cdp" });
  const browser = await chromium.connectOverCDP(grant.url, { noDefaults: true });
  try {
    const downloadPolicy = await browser.newBrowserCDPSession();
    try {
      await downloadPolicy.send("Browser.setDownloadBehavior", {
        behavior: "allow",
        downloadPath: session.downloadDirectory,
      });
    } finally {
      await downloadPolicy.detach();
    }
    const context = browser.contexts()[0];
    const page = context.pages()[0] ?? await context.newPage();
    await page.setContent('<input id="document" type="file"><a id="export">Download</a>');

    const uploaded = await client.sessions.files.upload(session.id, {
      filename: "input.csv",
      contentType: "text/csv",
      file: new TextEncoder().encode("name,value\nexample,1\n"),
    });

    const cdp = await context.newCDPSession(page);
    try {
      const document = await cdp.send("DOM.getDocument");
      const input = await cdp.send("DOM.querySelector", {
        nodeId: document.root.nodeId,
        selector: "#document",
      });
      if (!input.nodeId) throw new Error("File input missing");
      await cdp.send("DOM.setFileInputFiles", {
        nodeId: input.nodeId,
        files: [uploaded.browserPath],
      });
    } finally {
      await cdp.detach();
    }

    const selected = await page.locator("#document").inputValue();
    if (!selected.endsWith("input.csv")) throw new Error("Upload not selected");

    await page.evaluate(() => {
      const link = document.querySelector<HTMLAnchorElement>("#export");
      if (!link) throw new Error("Download link missing");
      link.download = "result.csv";
      link.href = URL.createObjectURL(new Blob(["status\ncomplete\n"], {
        type: "text/csv",
      }));
    });
    await page.locator("#export").click();

    const deadline = Date.now() + 20_000;
    let fileId: string | undefined;
    while (!fileId && Date.now() < deadline) {
      let cursor: string | undefined;
      do {
        const files = await client.sessions.files.list(session.id, {
          origin: "download",
          cursor,
        });
        fileId = files.items.find(
          (file) => file.status === "ready" && file.filename === "result.csv",
        )?.id;
        cursor = files.nextCursor ?? undefined;
      } while (!fileId && cursor);
      if (!fileId) await delay(250);
    }
    if (!fileId) throw new Error("Download did not become ready");

    const output = await open("result.csv", "w");
    try {
      const download = await client.sessions.files.download(session.id, fileId);
      try {
        for await (const chunk of download) await output.writeFile(chunk);
      } finally {
        await download.close();
      }
    } finally {
      await output.close();
    }
    console.log("Saved result.csv");
  } finally {
    await browser.close();
  }
});