Middleware

Cog supports middleware functions to process requests before they reach route handlers. Middleware can modify request and response objects or end the request early.

How to use middleware

Middleware functions receive (req, res, next) parameters. Call next() to pass control to the next middleware or route handler.

app.use("*", (req, _res, next) => {
    console.log(`${req.method} ${req.url}`);
    next();
});

Applying middleware to specific routes

You can apply middleware only to certain routes:

app.use("/admin", (req, res, next) => {
    if (!req.headers["authorization"]) {
        return res.send({ error: "Unauthorized" }, 401);
    }

    next();
});