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Version: 3.18

RouterHandler <Context, Routes>

Simple router that works based on request labels. This instance can then serve as a requestHandler of your crawler.

import { Router, CheerioCrawler, CheerioCrawlingContext } from 'crawlee';

const router = Router.create<CheerioCrawlingContext>();

// we can also use factory methods for specific crawling contexts, the above equals to:
// import { createCheerioRouter } from 'crawlee';
// const router = createCheerioRouter();

router.addHandler('label-a', async (ctx) => {
   ctx.log.info('...');
});
router.addDefaultHandler(async (ctx) => {
   ctx.log.info('...');
});

const crawler = new CheerioCrawler({
    requestHandler: router,
});
await crawler.run();

Alternatively we can use the default router instance from crawler object:

import { CheerioCrawler } from 'crawlee';

const crawler = new CheerioCrawler();

crawler.router.addHandler('label-a', async (ctx) => {
   ctx.log.info('...');
});
crawler.router.addDefaultHandler(async (ctx) => {
   ctx.log.info('...');
});

await crawler.run();

For convenience, we can also define the routes right when creating the router:

import { CheerioCrawler, createCheerioRouter } from 'crawlee';
const crawler = new CheerioCrawler({
    requestHandler: createCheerioRouter({
        'label-a': async (ctx) => { ... },
        'label-b': async (ctx) => { ... },
    })},
});
await crawler.run();

Middlewares are also supported via the router.use method. There can be multiple middlewares for a single router, they will be executed sequentially in the same order as they were registered.

crawler.router.use(async (ctx) => {
   ctx.log.info('...');
});

To get request.userData typed per label, declare a route map and pass it as the second type argument. The label passed to Router.addHandler then drives the type of request.userData, and unknown labels are rejected at compile time:

import { createCheerioRouter, CheerioCrawlingContext } from 'crawlee';

interface Routes {
    PRODUCT: { sku: string; price: number };
    CATEGORY: { categoryId: string };
}

const router = createCheerioRouter<CheerioCrawlingContext, Routes>();

router.addHandler('PRODUCT', async ({ request }) => {
    request.userData.sku;   // string
    request.userData.price; // number
});

router.addHandler('TYPO', async () => {}); // compile error: not a known label

Passing a Standard Schema per label instead of a plain type both infers the request.userData types and validates them at runtime — when the request is handled, and when it is added to the crawler (crawler.addRequests, context.addRequests, enqueueLinks). A failing request throws a RequestValidationError.

import { z } from 'zod';
import { createCheerioRouter } from 'crawlee';

const router = createCheerioRouter({
    PRODUCT: z.object({ sku: z.string(), price: z.number() }),
    CATEGORY: z.object({ categoryId: z.string() }),
});

router.addHandler('PRODUCT', async ({ request }) => {
    request.userData.price; // number, inferred from the schema and validated at runtime
});

Hierarchy

  • Router<Context, Routes>
    • RouterHandler

Callable

  • RouterHandler(ctx): Awaitable<void>

  • Parameters

    • ctx: Context

    Returns Awaitable<void>

Index

Methods

Methods

inheritedaddDefaultHandler

  • addDefaultHandler<UserData>(handler): void

  • Registers default route handler. As a fallback it can receive any request (including labels not declared in the route map). When the router was created with a defaultRoute schema, request.userData is typed from it; otherwise it defaults to the context's (loosely typed) userData. Pass an explicit UserData type argument to narrow it.

    Parameters

    • handler: (ctx) => Awaitable<void>

      Returns void

    inheritedaddHandler

    • addHandler<Label>(label, handler): void
    • addHandler<UserData>(label, handler): void

    • Registers new route handler for given label. When the router declares a route map, the label is restricted to the declared labels and request.userData is typed accordingly.

      Parameters

      • label: Label
      • handler: (ctx) => Awaitable<void>

        Returns void

      inheritedgetHandler

      • getHandler(label): (ctx) => Awaitable<void>

      • Returns route handler for given label. If no label is provided, the default request handler will be returned.

        Parameters

        • optionallabel: string | symbol

        Returns (ctx) => Awaitable<void>

          • (ctx): Awaitable<void>

          • Parameters

            • ctx: Context

            Returns Awaitable<void>

      inheriteduse

      • use(middleware): void

      • Registers a middleware that will be fired before the matching route handler. Multiple middlewares can be registered, they will be fired in the same order.

        Parameters

        • middleware: (ctx) => Awaitable<void>

          Returns void

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