abstractBrowserCrawler <InternalBrowserPoolOptions, LaunchOptions, Context, GoToOptions>
Hierarchy
- BasicCrawler<Context>
- BrowserCrawler
Index
Properties
optionalautoscaledPool
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 callingautoscaledPool.pause()or to abort it by callingautoscaledPool.abort().
browserPool
A reference to the underlying BrowserPool class that manages the crawler's browsers.
readonlyconfig
launchContext
optionalproxyConfiguration
A reference to the underlying ProxyConfiguration class that manages the crawler's proxies. Only available if used by the crawler.
optionalrequestList
A reference to the underlying RequestList class that manages the crawler's requests. Only available if used by the crawler.
optionalrequestQueue
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.
readonlyrouter
Default Router instance that will be used if we don't specify any requestHandler.
See router.addHandler() and router.addDefaultHandler().
optionalsessionPool
A reference to the underlying SessionPool class that manages the crawler's sessions. Only available if used by the crawler.
readonlystats
A reference to the underlying Statistics class that collects and logs run statistics for requests.
Methods
addRequests
Adds requests to be processed by the crawler
Parameters
requests: (string | RequestOptions<Dictionary<any>> | Request<Dictionary<any>>)[]
The requests to add
options: CrawlerAddRequestsOptions = {}
Options for the request queue
Returns Promise<CrawlerAddRequestsResult>
getRequestQueue
Returns Promise<RequestQueue>
run
Runs the crawler. Returns a promise that gets resolved once all the requests are processed. We can use the
requestsparameter to enqueue the initial requests - it is a shortcut for runningcrawler.addRequests()before thecrawler.run().Parameters
optionalrequests: (string | RequestOptions<Dictionary<any>> | Request<Dictionary<any>>)[]
The requests to add
optionaloptions: CrawlerAddRequestsOptions
Options for the request queue
Returns Promise<FinalStatistics>
useState
Type parameters
- State: Dictionary<any> = Dictionary<any>
Parameters
defaultValue: State = ...
Returns Promise<State>
Provides a simple framework for parallel crawling of web pages using headless browsers with Puppeteer and Playwright. 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
BrowserCrawleruses headless (or even headful) browsers 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, we should consider using the CheerioCrawler, which downloads the pages using raw HTTP requests and is about 10x faster.The source URLs are represented by the Request objects that are fed from the RequestList or RequestQueue instances provided by the
requestListorrequestQueueconstructor options, respectively. If neitherrequestListnorrequestQueueoptions are provided, the crawler will open the default request queue either when thecrawler.addRequests()function is called, or ifrequestsparameter (representing the initial requests) of thecrawler.run()function is provided.If both
requestListandrequestQueueoptions are used, the instance first processes URLs from the RequestList and automatically enqueues all of them to the 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.
BrowserCrawleropens a new browser page (i.e. tab or window) for each Request object to crawl and then calls the function provided by user as therequestHandleroption.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
autoscaledPoolOptionsparameter of theBrowserCrawlerconstructor. For user convenience, theminConcurrencyandmaxConcurrencyoptions of the underlying AutoscaledPool constructor are available directly in theBrowserCrawlerconstructor.