Consume Subscriptions API

A subscription worker can be created using the following GetSubscriptionWorker methods available through the Subscriptions property of the DocumentStore.

Note: Simply creating the worker is insufficient;
after creating the worker, you need to run the subscription worker to initiate document processing.

SubscriptionWorker<dynamic> GetSubscriptionWorker(
    string subscriptionName, string database = null);

SubscriptionWorker<dynamic> GetSubscriptionWorker(
    SubscriptionWorkerOptions options, string database = null);

SubscriptionWorker<T> GetSubscriptionWorker<T>(
    string subscriptionName, string database = null) where T : class;

SubscriptionWorker<T> GetSubscriptionWorker<T>(
    SubscriptionWorkerOptions options, string database = null) where T : class;

public class SubscriptionWorkerOptions
{
    public string SubscriptionName { get; }
    public int MaxDocsPerBatch { get; set; }
    public int SendBufferSizeInBytes { get; set; }
    public int ReceiveBufferSizeInBytes { get; set; }
    public bool IgnoreSubscriberErrors { get; set; }
    public bool CloseWhenNoDocsLeft { get; set; }
    public TimeSpan TimeToWaitBeforeConnectionRetry { get; set; }
    public TimeSpan ConnectionStreamTimeout { get; set; }
    public TimeSpan MaxErroneousPeriod { get; set; }
    public SubscriptionOpeningStrategy Strategy { get; set; }
}

When creating a worker with SubscriptionWorkerOptions, the only mandatory property is SubscriptionName.
All other parameters are optional and will default to their respective default values if not specified.

Learn more about SubscriptionOpeningStrategy in worker strategies.

public enum SubscriptionOpeningStrategy
{
    // Connect if no other worker is connected 
    OpenIfFree,
    
    // Take over the connection 
    TakeOver,
    
    // Wait for currently connected worker to disconnect 
    WaitForFree,
    
    // Connect concurrently  
    Concurrent
}

After creating a subscription worker, the subscription worker is still not processing any documents.
To start processing, you need to call the Run method of the SubscriptionWorker.

The Run function takes a delegate, which is your client-side code responsible for processing the received document batches.

Task Run(Action<SubscriptionBatch<T>> processDocuments,
    CancellationToken ct = default(CancellationToken));

Task Run(Func<SubscriptionBatch<T>, Task> processDocuments,
    CancellationToken ct = default(CancellationToken));

This class represents a single item in a subscription batch results.

public struct Item
{
    public T Result { get; internal set; }
    public string ExceptionMessage { get; internal set; }
    public string Id { get; internal set; }
    public string ChangeVector { get; internal set; }
    public bool Projection { get; internal set; }
    public bool Revision { get; internal set; }
    public BlittableJsonReaderObject RawResult { get; internal set; }
    public BlittableJsonReaderObject RawMetadata { get; internal set; }
    public IMetadataDictionary Metadata { get; internal set; }
}