Middlewares

Harpia supports both route middlewares and global middlewares.

Route Middleware

You can define route-specific middleware in two ways:

Inline within the route

You can define one or more middleware functions directly in the route declaration:

route.get(
  "/",
  (req: Request, res: Response, next: NextFunction) => {
    console.log("first middleware");
    next();
  },
  (req: Request, res: Response, next: NextFunction) => {
    console.log("second middleware");
    next();
  },
  (req: Request, res: Response) => {
    console.log("handler");
    return res.send("hello");
  }
);

Each middleware has access to req, res, and next. Call next() to pass control to the next middleware or the final handler.

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Using app.use() with a prefix

You can attach middleware to a route prefix using app.use():

app.use("/users", (req: Request, res: Response, next: NextFunction) => {
  console.log("check user");
  next();
});

This middleware will run for any route that starts with /users.

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Global Middleware

Global middleware applies to all routes and is also defined using app.use(), but without specifying a route path:

app.use((req: Request, res: Response, next: NextFunction) => {
  console.log("global check");
  next();
});

Use global middleware for things like logging, authentication checks, or response timing.

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All middleware functions must call next() to pass control unless a response is sent or an error is thrown.