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PuppeteerCrawler

Provides a simple framework for parallel crawling of web pages using headless Chrome with Puppeteer. The URLs to crawl are fed either from a static list of URLs or from a dynamic queue of URLs enabling recursive crawling of websites.

Since PuppeteerCrawler uses headless Chrome to download web pages and extract data, it is useful for crawling of websites that require to execute JavaScript. If the target website doesn't need JavaScript, consider using CheerioCrawler, which downloads the pages using raw HTTP requests and is about 10x faster.

The source URLs are represented using Request objects that are fed from RequestList or RequestQueue instances provided by the PuppeteerCrawlerOptions.requestList or PuppeteerCrawlerOptions.requestQueue constructor options, respectively.

If both PuppeteerCrawlerOptions.requestList and PuppeteerCrawlerOptions.requestQueue are used, the instance first processes URLs from the RequestList and automatically enqueues all of them to RequestQueue before it starts their processing. This ensures that a single URL is not crawled multiple times.

The crawler finishes when there are no more Request objects to crawl.

PuppeteerCrawler opens a new Chrome page (i.e. tab) for each Request object to crawl and then calls the function provided by user as the PuppeteerCrawlerOptions.requestHandler option.

New pages are only opened when there is enough free CPU and memory available, using the functionality provided by the AutoscaledPool class. All AutoscaledPool configuration options can be passed to the PuppeteerCrawlerOptions.autoscaledPoolOptions parameter of the PuppeteerCrawler constructor. For user convenience, the minConcurrency and maxConcurrency AutoscaledPoolOptions are available directly in the PuppeteerCrawler constructor.

Note that the pool of Puppeteer instances is internally managed by the BrowserPool class.

Example usage:

const crawler = new PuppeteerCrawler({
    async requestHandler({ page, request }) {
        // This function is called to extract data from a single web page
        // 'page' is an instance of Puppeteer.Page with page.goto(request.url) already called
        // 'request' is an instance of Request class with information about the page to load
        await Dataset.pushData({
            title: await page.title(),
            url: request.url,
            succeeded: true,
        })
    },
    async failedRequestHandler({ request }) {
        // This function is called when the crawling of a request failed too many times
        await Dataset.pushData({
            url: request.url,
            succeeded: false,
            errors: request.errorMessages,
        })
    },
});

await crawler.run([
    'http://www.example.com/page-1',
    'http://www.example.com/page-2',
]);

Hierarchy

Index

Constructors

Properties

Methods

Constructors

constructor

  • All PuppeteerCrawler parameters are passed via an options object.

    Parameters

    Returns PuppeteerCrawler

Properties

optionalinheritedautoscaledPool

autoscaledPool?: AutoscaledPool

A reference to the underlying AutoscaledPool class that manages the concurrency of the crawler.

NOTE: This property is only initialized after calling the crawler.run() function. We can use it to change the concurrency settings on the fly, to pause the crawler by calling autoscaledPool.pause() or to abort it by calling autoscaledPool.abort().

inheritedbrowserPool

browserPool: BrowserPool<{ browserPlugins: [PuppeteerPlugin] }, [PuppeteerPlugin], BrowserController<PuppeteerNode, PuppeteerLaunchOptions, Browser, PuppeteerNewPageOptions, Page>, LaunchContext<PuppeteerNode, PuppeteerLaunchOptions, Browser, PuppeteerNewPageOptions, Page>, undefined | PuppeteerNewPageOptions, Page>

A reference to the underlying BrowserPool class that manages the crawler's browsers.

readonlyinheritedconfig

config: Configuration = ...

inheritedhasFinishedBefore

hasFinishedBefore: boolean = false

inheritedlaunchContext

launchContext: BrowserLaunchContext<LaunchOptions, unknown>

readonlyinheritedlog

log: Log

optionalinheritedproxyConfiguration

proxyConfiguration?: ProxyConfiguration

A reference to the underlying ProxyConfiguration class that manages the crawler's proxies. Only available if used by the crawler.

optionalinheritedrequestList

requestList?: IRequestList

A reference to the underlying RequestList class that manages the crawler's requests. Only available if used by the crawler.

optionalinheritedrequestQueue

requestQueue?: RequestProvider

Dynamic queue of URLs to be processed. This is useful for recursive crawling of websites. A reference to the underlying RequestQueue class that manages the crawler's requests. Only available if used by the crawler.

readonlyinheritedrouter

router: RouterHandler<{ request: LoadedRequest<Request<Dictionary>> } & Omit<PuppeteerCrawlingContext<Dictionary>, request>> = ...

Default Router instance that will be used if we don't specify any requestHandler. See router.addHandler() and router.addDefaultHandler().

inheritedrunning

running: boolean = false

optionalinheritedsessionPool

sessionPool?: SessionPool

A reference to the underlying SessionPool class that manages the crawler's sessions. Only available if used by the crawler.

readonlyinheritedstats

stats: Statistics

A reference to the underlying Statistics class that collects and logs run statistics for requests.

Methods

inheritedaddRequests

  • Adds requests to the queue in batches. By default, it will resolve after the initial batch is added, and continue adding the rest in background. You can configure the batch size via batchSize option and the sleep time in between the batches via waitBetweenBatchesMillis. If you want to wait for all batches to be added to the queue, you can use the waitForAllRequestsToBeAdded promise you get in the response object.

    This is an alias for calling addRequestsBatched() on the implicit RequestQueue for this crawler instance.

    Parameters

    Returns Promise<CrawlerAddRequestsResult>

inheritedexportData

  • Retrieves all the data from the default crawler Dataset and exports them to the specified format. Supported formats are currently 'json' and 'csv', and will be inferred from the path automatically.

    Parameters

    Returns Promise<Data[]>

inheritedgetData

inheritedgetDataset

  • getDataset(idOrName?: string): Promise<Dataset<Dictionary>>

  • Retrieves the specified Dataset, or the default crawler Dataset.

    Parameters

    • optionalidOrName: string

    Returns Promise<Dataset<Dictionary>>

inheritedgetRequestQueue

  • Returns Promise<RequestProvider>

inheritedpushData

  • pushData(data: Dictionary | Dictionary[], datasetIdOrName?: string): Promise<void>

  • Pushes data to the specified Dataset, or the default crawler Dataset by calling Dataset.pushData.

    Parameters

    • data: Dictionary | Dictionary[]
    • optionaldatasetIdOrName: string

    Returns Promise<void>

inheritedrun

  • Runs the crawler. Returns a promise that gets resolved once all the requests are processed. We can use the requests parameter to enqueue the initial requests - it is a shortcut for running crawler.addRequests() before the crawler.run().

    Parameters

    Returns Promise<FinalStatistics>

inheritedsetStatusMessage

  • This method is periodically called by the crawler, every statusMessageLoggingInterval seconds.

    Parameters

    Returns Promise<void>

inheriteduseState

  • useState(defaultValue?: State): Promise<State>

  • Parameters

    • defaultValue: State = ...

    Returns Promise<State>

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