Request & Response

bunWay provides Express-compatible request and response objects with all the methods you expect.

Cache Validation

req.fresh / req.stale

Check if the client's cached version is still valid:

app.get("/data", (req, res) => {
  // Set cache headers
  res.set("ETag", '"v1"');

  // Check if client cache is fresh
  if (req.fresh) {
    res.status(304).end();
    return;
  }

  res.json({ data: computeExpensiveData() });
});

How it works:

• Only GET and HEAD requests can be fresh
• Compares If-None-Match against response ETag (weak comparison)
• Compares If-Modified-Since against response Last-Modified
• When If-None-Match is present, it takes full precedence — If-Modified-Since is ignored
• Cache-Control: no-cache always returns stale
• req.stale is the inverse of req.fresh

Range Requests

req.range(size, options?)

Parse the Range header for partial content support:

app.get("/video/:id", (req, res) => {
  const fileSize = getFileSize(req.params.id);
  const ranges = req.range(fileSize);

  if (ranges === -1) return res.status(416).end(); // Unsatisfiable
  if (ranges === -2) return res.status(400).end(); // Malformed
  if (!ranges) {
    // No Range header — send full file
    return res.sendFile(`./videos/${req.params.id}`);
  }

  // Handle first range
  const { start, end } = ranges[0];
  // ... serve partial content
});

Return values:

• undefined — no Range header present
• -2 — malformed Range header
• -1 — unsatisfiable range (all ranges invalid)
• Array<{ start, end }> — parsed ranges with .type property ("bytes")

Options:

• combine: true — merge overlapping/adjacent ranges

Automatic Range Support in res.sendFile()

res.sendFile() automatically handles Range requests:

app.get("/download/:file", async (req, res) => {
  await res.sendFile(`./files/${req.params.file}`);
  // Automatically:
  // - Sets Accept-Ranges: bytes
  // - Returns 206 with Content-Range for range requests
  // - Returns 416 for unsatisfiable ranges
  // - Returns 200 with full file when no Range header
});

JSONP

res.jsonp(data)

Send a JSONP response for legacy cross-domain clients:

app.get("/api/data", (req, res) => {
  res.jsonp({ name: "bunway" });
});
// GET /api/data?callback=myFunc → myFunc({"name":"bunway"});
// GET /api/data → {"name":"bunway"} (plain JSON fallback)

Configure callback parameter name:

app.set("jsonp callback name", "cb");
// Now: GET /api/data?cb=myFunc

Default callback parameter name is "callback".

Cross-References

req.res / res.req / res.app

Access the paired objects from either side:

app.get("/test", (req, res) => {
  req.res === res;    // true — access response from request
  res.req === req;    // true — access request from response
  res.app !== undefined; // true — access app from response
});

These are set automatically during request dispatch.

Array Paths

app.use([path1, path2], handler)

Register middleware or routers for multiple paths at once:

// Middleware on multiple paths
app.use(["/api", "/rest"], corsMiddleware);

// Sub-router on multiple paths
const apiRouter = new Router();
apiRouter.get("/health", (req, res) => res.json({ ok: true }));
app.use(["/v1", "/v2"], apiRouter);
// Both /v1/health and /v2/health work