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RequestQueue

Represents a queue of URLs to crawl, which is used for deep crawling of websites where you start with several URLs and then recursively follow links to other pages. The data structure supports both breadth-first and depth-first crawling orders.

Each URL is represented using an instance of the Request class. The queue can only contain unique URLs. More precisely, it can only contain Request instances with distinct uniqueKey properties. By default, uniqueKey is generated from the URL, but it can also be overridden. To add a single URL multiple times to the queue, corresponding Request objects will need to have different uniqueKey properties.

Do not instantiate this class directly, use the RequestQueue.open function instead.

RequestQueue is used by BasicCrawler, CheerioCrawler, PuppeteerCrawler and PlaywrightCrawler as a source of URLs to crawl. Unlike RequestList, RequestQueue supports dynamic adding and removing of requests. On the other hand, the queue is not optimized for operations that add or remove a large number of URLs in a batch.

RequestQueue stores its data either on local disk or in the Apify Cloud, depending on whether the APIFY_LOCAL_STORAGE_DIR or APIFY_TOKEN environment variable is set.

If the APIFY_LOCAL_STORAGE_DIR environment variable is set, the queue data is stored in that directory in an SQLite database file.

If the APIFY_TOKEN environment variable is set but APIFY_LOCAL_STORAGE_DIR is not, the data is stored in the Apify Request Queue cloud storage. Note that you can force usage of the cloud storage also by passing the forceCloud option to RequestQueue.open function, even if the APIFY_LOCAL_STORAGE_DIR variable is set.

Example usage:

// Open the default request queue associated with the crawler run
const queue = await RequestQueue.open();

// Open a named request queue
const queueWithName = await RequestQueue.open('some-name');

// Enqueue few requests
await queue.addRequest({ url: 'http://example.com/aaa' });
await queue.addRequest({ url: 'http://example.com/bbb' });
await queue.addRequest({ url: 'http://example.com/foo/bar' }, { forefront: true });

Index

Properties

Methods

Properties

assumedHandledCount

assumedHandledCount: number = 0

assumedTotalCount

assumedTotalCount: number = 0

client

client: RequestQueueClient

clientKey

clientKey: string = ...

readonlyconfig

config: Configuration = ...

id

id: string

inProgress

inProgress: Set<unknown> = ...

internalTimeoutMillis

internalTimeoutMillis: number = ...

lastActivity

lastActivity: Date = ...

log

log: Log = ...

optionalname

name?: string

optionalqueryQueueHeadPromise

queryQueueHeadPromise?: null | Promise<{ hadMultipleClients?: boolean; prevLimit: number; queryStartedAt: Date; queueModifiedAt: Date; wasLimitReached: boolean }> = null

recentlyHandled

recentlyHandled: LruCache<any> = ...

requestsCache

requestsCache: LruCache<Pick<QueueOperationInfo, uniqueKey | wasAlreadyHandled> & { id: string; isHandled: boolean }> = ...

timeoutSecs

timeoutSecs: number = 30

Methods

addRequest

  • Adds a request to the queue.

    If a request with the same uniqueKey property is already present in the queue, it will not be updated. You can find out whether this happened from the resulting QueueOperationInfo object.

    To add multiple requests to the queue by extracting links from a webpage, see the enqueueLinks helper function.

    Parameters

    Returns Promise<QueueOperationInfo>

addRequests

  • Adds requests to the queue in batches of 25.

    If a request that is passed in is already present due to its uniqueKey property being the same, it will not be updated. You can find out whether this happened by finding the request in the resulting BatchAddRequestsResult object.

    @experimental

    Parameters

    Returns Promise<BatchAddRequestsResult>

drop

  • drop(): Promise<void>

  • Removes the queue either from the Apify Cloud storage or from the local database, depending on the mode of operation.

    Returns Promise<void>

fetchNextRequest

  • fetchNextRequest<T>(): Promise<null | Request<T>>

  • Returns a next request in the queue to be processed, or null if there are no more pending requests.

    Once you successfully finish processing of the request, you need to call RequestQueue.markRequestHandled to mark the request as handled in the queue. If there was some error in processing the request, call RequestQueue.reclaimRequest instead, so that the queue will give the request to some other consumer in another call to the fetchNextRequest function.

    Note that the null return value doesn’t mean the queue processing finished, it means there are currently no pending requests. To check whether all requests in queue were finished, use RequestQueue.isFinished instead.

    Type parameters

    • T: Dictionary<any> = Dictionary<any>

    Returns Promise<null | Request<T>>

    Returns the request object or null if there are no more pending requests.

getInfo

  • Returns an object containing general information about the request queue.

    The function returns the same object as the Apify API Client’s getQueue function, which in turn calls the Get request queue API endpoint.

    Example:

    {
      id: "WkzbQMuFYuamGv3YF",
      name: "my-queue",
      userId: "wRsJZtadYvn4mBZmm",
      createdAt: new Date("2015-12-12T07:34:14.202Z"),
      modifiedAt: new Date("2015-12-13T08:36:13.202Z"),
      accessedAt: new Date("2015-12-14T08:36:13.202Z"),
      totalRequestCount: 25,
      handledRequestCount: 5,
      pendingRequestCount: 20,
    }

    Returns Promise<undefined | RequestQueueInfo>

getRequest

  • getRequest<T>(id: string): Promise<null | Request<T>>

  • Gets the request from the queue specified by ID.

    Type parameters

    • T: Dictionary<any> = Dictionary<any>

    Parameters

    • id: string

      ID of the request.

    Returns Promise<null | Request<T>>

    Returns the request object, or null if it was not found.

handledCount

  • handledCount(): Promise<number>

  • Returns the number of handled requests.

    This function is just a convenient shortcut for:

    const { handledRequestCount } = await queue.getInfo();

    Returns Promise<number>

isEmpty

  • isEmpty(): Promise<boolean>

  • Resolves to true if the next call to RequestQueue.fetchNextRequest would return null, otherwise it resolves to false. Note that even if the queue is empty, there might be some pending requests currently being processed. If you need to ensure that there is no activity in the queue, use RequestQueue.isFinished.

    Returns Promise<boolean>

isFinished

  • isFinished(): Promise<boolean>

  • Resolves to true if all requests were already handled and there are no more left. Due to the nature of distributed storage used by the queue, the function might occasionally return a false negative, but it will never return a false positive.

    Returns Promise<boolean>

markRequestHandled

  • Marks a request that was previously returned by the RequestQueue.fetchNextRequest function as handled after successful processing. Handled requests will never again be returned by the fetchNextRequest function.

    Parameters

    Returns Promise<null | QueueOperationInfo>

reclaimRequest

  • Reclaims a failed request back to the queue, so that it can be returned for processing later again by another call to RequestQueue.fetchNextRequest. The request record in the queue is updated using the provided request parameter. For example, this lets you store the number of retries or error messages for the request.

    Parameters

    Returns Promise<null | QueueOperationInfo>

staticopen

  • Opens a request queue and returns a promise resolving to an instance of the RequestQueue class.

    RequestQueue represents a queue of URLs to crawl, which is stored either on local filesystem or in the cloud. The queue is used for deep crawling of websites, where you start with several URLs and then recursively follow links to other pages. The data structure supports both breadth-first and depth-first crawling orders.

    For more details and code examples, see the RequestQueue class.

    Parameters

    Returns Promise<RequestQueue>