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Version: 3.0

@crawlee/basic

Provides a simple framework for parallel crawling of web pages. 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.

BasicCrawler is a low-level tool that requires the user to implement the page download and data extraction functionality themselves. If we want a crawler that already facilitates this functionality, we should consider using CheerioCrawler, PuppeteerCrawler or PlaywrightCrawler.

BasicCrawler invokes the user-provided requestHandler for each Request object, which represents a single URL to crawl. The Request objects are fed from the RequestList or RequestQueue instances provided by the requestList or requestQueue constructor options, respectively. If neither requestList nor requestQueue options are provided, the crawler will open the default request queue either when the crawler.addRequests() function is called, or if requests parameter (representing the initial requests) of the crawler.run() function is provided.

If both requestList and requestQueue options 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 if there are no more Request objects to crawl.

New requests are only dispatched 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 autoscaledPoolOptions parameter of the BasicCrawler constructor. For user convenience, the minConcurrency and maxConcurrency options of the underlying AutoscaledPool constructor are available directly in the BasicCrawler constructor.

Example usage​

import { BasicCrawler, Dataset } from 'crawlee';

// Create a crawler instance
const crawler = new BasicCrawler({
    async requestHandler({ request, sendRequest }) {
        // 'request' contains an instance of the Request class
        // Here we simply fetch the HTML of the page and store it to a dataset
        const { body } = await sendRequest({
            url: request.url,
            method: request.method,
            body: request.payload,
            headers: request.headers,
        });

        await Dataset.pushData({
            url: request.url,
            html: body,
        })
    },
});

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

Index

References

Crawlers

Interfaces

Type Aliases

Variables

Functions

References

AutoscaledPool

Re-exports AutoscaledPool

AutoscaledPoolOptions

Re-exports AutoscaledPoolOptions

ClientInfo

Re-exports ClientInfo

Configuration

Re-exports Configuration

ConfigurationOptions

Re-exports ConfigurationOptions

CrawlingContext

Re-exports CrawlingContext

CreateSession

Re-exports CreateSession

CriticalError

Re-exports CriticalError

Dataset

Re-exports Dataset

DatasetConsumer

Re-exports DatasetConsumer

DatasetContent

Re-exports DatasetContent

DatasetDataOptions

Re-exports DatasetDataOptions

DatasetIteratorOptions

Re-exports DatasetIteratorOptions

DatasetMapper

Re-exports DatasetMapper

DatasetOptions

Re-exports DatasetOptions

DatasetReducer

Re-exports DatasetReducer

EnqueueLinksOptions

Re-exports EnqueueLinksOptions

EnqueueStrategy

Re-exports EnqueueStrategy

EventManager

Re-exports EventManager

EventType

Re-exports EventType

EventTypeName

Re-exports EventTypeName

FinalStatistics

Re-exports FinalStatistics

GlobInput

Re-exports GlobInput

GlobObject

Re-exports GlobObject

IStorage

Re-exports IStorage

KeyConsumer

Re-exports KeyConsumer

KeyValueStore

Re-exports KeyValueStore

KeyValueStoreIteratorOptions

Re-exports KeyValueStoreIteratorOptions

KeyValueStoreOptions

Re-exports KeyValueStoreOptions

LocalEventManager

Re-exports LocalEventManager

Log

Re-exports Log

LogLevel

Re-exports LogLevel

Logger

Re-exports Logger

LoggerJson

Re-exports LoggerJson

LoggerOptions

Re-exports LoggerOptions

LoggerText

Re-exports LoggerText

NonRetryableError

Re-exports NonRetryableError

ProxyConfiguration

Re-exports ProxyConfiguration

ProxyConfigurationFunction

Re-exports ProxyConfigurationFunction

ProxyConfigurationOptions

Re-exports ProxyConfigurationOptions

ProxyInfo

Re-exports ProxyInfo

PseudoUrl

Re-exports PseudoUrl

PseudoUrlInput

Re-exports PseudoUrlInput

PseudoUrlObject

Re-exports PseudoUrlObject

PushErrorMessageOptions

Re-exports PushErrorMessageOptions

QueueOperationInfo

Re-exports QueueOperationInfo

QueueOperationInfoOptions

Re-exports QueueOperationInfoOptions

RecordOptions

Re-exports RecordOptions

RegExpInput

Re-exports RegExpInput

RegExpObject

Re-exports RegExpObject

Request

Re-exports Request

RequestList

Re-exports RequestList

RequestListOptions

Re-exports RequestListOptions

RequestListSourcesFunction

Re-exports RequestListSourcesFunction

RequestListState

Re-exports RequestListState

RequestOptions

Re-exports RequestOptions

RequestQueue

Re-exports RequestQueue

RequestQueueOperationOptions

Re-exports RequestQueueOperationOptions

RequestQueueOptions

Re-exports RequestQueueOptions

RequestTransform

Re-exports RequestTransform

RetryRequestError

Re-exports RetryRequestError

Router

Re-exports Router

RouterHandler

Re-exports RouterHandler

Session

Re-exports Session

SessionOptions

Re-exports SessionOptions

SessionPool

Re-exports SessionPool

SessionPoolOptions

Re-exports SessionPoolOptions

SessionState

Re-exports SessionState

Snapshotter

Re-exports Snapshotter

SnapshotterOptions

Re-exports SnapshotterOptions

Source

Re-exports Source

StatisticPersistedState

Re-exports StatisticPersistedState

StatisticState

Re-exports StatisticState

Statistics

Re-exports Statistics

StorageClient

Re-exports StorageClient

StorageManagerOptions

Re-exports StorageManagerOptions

SystemInfo

Re-exports SystemInfo

SystemStatus

Re-exports SystemStatus

SystemStatusOptions

Re-exports SystemStatusOptions

UrlPatternObject

Re-exports UrlPatternObject

enqueueLinks

Re-exports enqueueLinks

log

Re-exports log

purgeDefaultStorages

Re-exports purgeDefaultStorages

Type Aliases

ErrorHandler

ErrorHandler<Context>: (inputs: Context, error: Error) => Awaitable<void>

Type parameters

Type declaration

    • (inputs: Context, error: Error): Awaitable<void>

    • Parameters

      • inputs: Context
      • error: Error

      Returns Awaitable<void>

RequestHandler

RequestHandler<Context>: (inputs: Context) => Awaitable<void>

Type parameters

Type declaration

    • (inputs: Context): Awaitable<void>

    • Parameters

      • inputs: Context

      Returns Awaitable<void>

Variables

constBASIC_CRAWLER_TIMEOUT_BUFFER_SECS

BASIC_CRAWLER_TIMEOUT_BUFFER_SECS: 10 = 10

Additional number of seconds used in CheerioCrawler and BrowserCrawler to set a reasonable requestHandlerTimeoutSecs for BasicCrawler that would not impare functionality (not timeout before crawlers).

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