Class Watcher<T>

Watcher for subscribing to mongodb change streams.

Inheritance

Object

Watcher<T>

Inherited Members

Object.Equals(Object)

Object.Equals(Object, Object)

Object.GetHashCode()

Object.GetType()

Object.MemberwiseClone()

Object.ReferenceEquals(Object, Object)

Object.ToString()

Namespace: MongoDB.Entities

Assembly: MongoDB.Entities.dll

Syntax

public class Watcher<T>
    where T : IEntity

Type Parameters

Name	Description
T	The type of entity

Properties

CanRestart

Returns true if watching can be restarted if it was stopped due to an error or invalidate event. Will always return false after cancellation is requested via the cancellation token.

Declaration

public bool CanRestart { get; }

Property Value

Type	Description
Boolean

IsInitialized

Indicates whether this watcher has already been initialized or not.

Declaration

public bool IsInitialized { get; }

Property Value

Type	Description
Boolean

Name

The name of this watcher instance

Declaration

public string Name { get; }

Property Value

Type	Description
String

ResumeToken

The last resume token received from mongodb server. Can be used to resume watching with .StartWithToken() method.

Declaration

public BsonDocument ResumeToken { get; }

Property Value

Type	Description
BsonDocument

Methods

ReStart(BsonDocument)

If the watcher stopped due to an error or invalidate event, you can try to restart the watching again with this method.

Declaration

public void ReStart(BsonDocument resumeToken = null)

Parameters

Type	Name	Description
BsonDocument	resumeToken	An optional resume token to restart watching with

Start(EventType, Func<FilterDefinitionBuilder<ChangeStreamDocument<T>>, FilterDefinition<ChangeStreamDocument<T>>>, Int32, Boolean, Boolean, CancellationToken)

Starts the watcher instance with the supplied parameters

Declaration

public void Start(EventType eventTypes, Func<FilterDefinitionBuilder<ChangeStreamDocument<T>>, FilterDefinition<ChangeStreamDocument<T>>> filter, int batchSize = 25, bool onlyGetIDs = false, bool autoResume = true, CancellationToken cancellation = default(CancellationToken))

Parameters

Type	Name	Description
EventType	eventTypes	Type of event to watch for. Specify multiple like: EventType.Created | EventType.Updated | EventType.Deleted
Func<FilterDefinitionBuilder<ChangeStreamDocument<T>>, FilterDefinition<ChangeStreamDocument<T>>>	filter	b => b.Eq(d => d.FullDocument.Prop1, "value")
Int32	batchSize	The max number of entities to receive for a single event occurence
Boolean	onlyGetIDs	Set to true if you don't want the complete entity details. All properties except the ID will then be null.
Boolean	autoResume	Set to false if you'd like to skip the changes that happened while the watching was stopped. This will also make you unable to retrieve a ResumeToken.
CancellationToken	cancellation	A cancellation token for ending the watching/change stream

Start(EventType, Expression<Func<T, T>>, Func<FilterDefinitionBuilder<ChangeStreamDocument<T>>, FilterDefinition<ChangeStreamDocument<T>>>, Int32, Boolean, CancellationToken)

Starts the watcher instance with the supplied parameters. Supports projection.

Declaration

public void Start(EventType eventTypes, Expression<Func<T, T>> projection, Func<FilterDefinitionBuilder<ChangeStreamDocument<T>>, FilterDefinition<ChangeStreamDocument<T>>> filter, int batchSize = 25, bool autoResume = true, CancellationToken cancellation = default(CancellationToken))

Parameters

Type	Name	Description
EventType	eventTypes	Type of event to watch for. Specify multiple like: EventType.Created | EventType.Updated | EventType.Deleted
Expression<Func<T, T>>	projection	A projection expression for the entity
Func<FilterDefinitionBuilder<ChangeStreamDocument<T>>, FilterDefinition<ChangeStreamDocument<T>>>	filter	b => b.Eq(d => d.FullDocument.Prop1, "value")
Int32	batchSize	The max number of entities to receive for a single event occurence
Boolean	autoResume	Set to false if you'd like to skip the changes that happened while the watching was stopped. This will also make you unable to retrieve a ResumeToken.
CancellationToken	cancellation	A cancellation token for ending the watching/change stream

Start(EventType, Expression<Func<T, T>>, Expression<Func<ChangeStreamDocument<T>, Boolean>>, Int32, Boolean, CancellationToken)

Starts the watcher instance with the supplied parameters. Supports projection.

Declaration

public void Start(EventType eventTypes, Expression<Func<T, T>> projection, Expression<Func<ChangeStreamDocument<T>, bool>> filter = null, int batchSize = 25, bool autoResume = true, CancellationToken cancellation = default(CancellationToken))

Parameters

Type	Name	Description
EventType	eventTypes	Type of event to watch for. Specify multiple like: EventType.Created | EventType.Updated | EventType.Deleted
Expression<Func<T, T>>	projection	A projection expression for the entity
Expression<Func<ChangeStreamDocument<T>, Boolean>>	filter	x => x.FullDocument.Prop1 == "SomeValue"
Int32	batchSize	The max number of entities to receive for a single event occurence
Boolean	autoResume	Set to false if you'd like to skip the changes that happened while the watching was stopped. This will also make you unable to retrieve a ResumeToken.
CancellationToken	cancellation	A cancellation token for ending the watching/change stream

Start(EventType, Expression<Func<ChangeStreamDocument<T>, Boolean>>, Int32, Boolean, Boolean, CancellationToken)

Starts the watcher instance with the supplied parameters

Declaration

public void Start(EventType eventTypes, Expression<Func<ChangeStreamDocument<T>, bool>> filter = null, int batchSize = 25, bool onlyGetIDs = false, bool autoResume = true, CancellationToken cancellation = default(CancellationToken))

Parameters

Type	Name	Description
EventType	eventTypes	Type of event to watch for. Specify multiple like: EventType.Created | EventType.Updated | EventType.Deleted
Expression<Func<ChangeStreamDocument<T>, Boolean>>	filter	x => x.FullDocument.Prop1 == "SomeValue"
Int32	batchSize	The max number of entities to receive for a single event occurence
Boolean	onlyGetIDs	Set to true if you don't want the complete entity details. All properties except the ID will then be null.
Boolean	autoResume	Set to false if you'd like to skip the changes that happened while the watching was stopped. This will also make you unable to retrieve a ResumeToken.
CancellationToken	cancellation	A cancellation token for ending the watching/change stream

StartWithToken(BsonDocument, EventType, Func<FilterDefinitionBuilder<ChangeStreamDocument<T>>, FilterDefinition<ChangeStreamDocument<T>>>, Int32, Boolean, CancellationToken)

Starts the watcher instance with the supplied configuration

Declaration

public void StartWithToken(BsonDocument resumeToken, EventType eventTypes, Func<FilterDefinitionBuilder<ChangeStreamDocument<T>>, FilterDefinition<ChangeStreamDocument<T>>> filter, int batchSize = 25, bool onlyGetIDs = false, CancellationToken cancellation = default(CancellationToken))

Parameters

Type	Name	Description
BsonDocument	resumeToken	A resume token to start receiving changes after some point back in time
EventType	eventTypes	Type of event to watch for. Specify multiple like: EventType.Created | EventType.Updated | EventType.Deleted
Func<FilterDefinitionBuilder<ChangeStreamDocument<T>>, FilterDefinition<ChangeStreamDocument<T>>>	filter	b => b.Eq(d => d.FullDocument.Prop1, "value")
Int32	batchSize	The max number of entities to receive for a single event occurence
Boolean	onlyGetIDs	Set to true if you don't want the complete entity details. All properties except the ID will then be null.
CancellationToken	cancellation	A cancellation token for ending the watching/change stream

StartWithToken(BsonDocument, EventType, Expression<Func<T, T>>, Func<FilterDefinitionBuilder<ChangeStreamDocument<T>>, FilterDefinition<ChangeStreamDocument<T>>>, Int32, CancellationToken)

Starts the watcher instance with the supplied configuration. Supports projection.

Declaration

public void StartWithToken(BsonDocument resumeToken, EventType eventTypes, Expression<Func<T, T>> projection, Func<FilterDefinitionBuilder<ChangeStreamDocument<T>>, FilterDefinition<ChangeStreamDocument<T>>> filter, int batchSize = 25, CancellationToken cancellation = default(CancellationToken))

Parameters

Type	Name	Description
BsonDocument	resumeToken	A resume token to start receiving changes after some point back in time
EventType	eventTypes	Type of event to watch for. Specify multiple like: EventType.Created | EventType.Updated | EventType.Deleted
Expression<Func<T, T>>	projection	A projection expression for the entity
Func<FilterDefinitionBuilder<ChangeStreamDocument<T>>, FilterDefinition<ChangeStreamDocument<T>>>	filter	b => b.Eq(d => d.FullDocument.Prop1, "value")
Int32	batchSize	The max number of entities to receive for a single event occurence
CancellationToken	cancellation	A cancellation token for ending the watching/change stream

StartWithToken(BsonDocument, EventType, Expression<Func<T, T>>, Expression<Func<ChangeStreamDocument<T>, Boolean>>, Int32, CancellationToken)

Starts the watcher instance with the supplied configuration. Supports projection.

Declaration

public void StartWithToken(BsonDocument resumeToken, EventType eventTypes, Expression<Func<T, T>> projection, Expression<Func<ChangeStreamDocument<T>, bool>> filter = null, int batchSize = 25, CancellationToken cancellation = default(CancellationToken))

Parameters

Type	Name	Description
BsonDocument	resumeToken	A resume token to start receiving changes after some point back in time
EventType	eventTypes	Type of event to watch for. Specify multiple like: EventType.Created | EventType.Updated | EventType.Deleted
Expression<Func<T, T>>	projection	A projection expression for the entity
Expression<Func<ChangeStreamDocument<T>, Boolean>>	filter	x => x.FullDocument.Prop1 == "SomeValue"
Int32	batchSize	The max number of entities to receive for a single event occurence
CancellationToken	cancellation	A cancellation token for ending the watching/change stream

StartWithToken(BsonDocument, EventType, Expression<Func<ChangeStreamDocument<T>, Boolean>>, Int32, Boolean, CancellationToken)

Starts the watcher instance with the supplied configuration

Declaration

public void StartWithToken(BsonDocument resumeToken, EventType eventTypes, Expression<Func<ChangeStreamDocument<T>, bool>> filter = null, int batchSize = 25, bool onlyGetIDs = false, CancellationToken cancellation = default(CancellationToken))

Parameters

Type	Name	Description
BsonDocument	resumeToken	A resume token to start receiving changes after some point back in time
EventType	eventTypes	Type of event to watch for. Specify multiple like: EventType.Created | EventType.Updated | EventType.Deleted
Expression<Func<ChangeStreamDocument<T>, Boolean>>	filter	x => x.FullDocument.Prop1 == "SomeValue"
Int32	batchSize	The max number of entities to receive for a single event occurence
Boolean	onlyGetIDs	Set to true if you don't want the complete entity details. All properties except the ID will then be null.
CancellationToken	cancellation	A cancellation token for ending the watching/change stream

Events

OnChanges

This event is fired when the desired types of events have occured. Will have a list of 'entities' that was received as input.

Declaration

public event Action<IEnumerable<T>> OnChanges

Event Type

Type	Description
Action<IEnumerable<T>>

OnChangesAsync

This event is fired when the desired types of events have occured. Will have a list of 'entities' that was received as input.

Declaration

public event AsyncEventHandler<IEnumerable<T>> OnChangesAsync

Event Type

Type	Description
AsyncEventHandler<IEnumerable<T>>

OnChangesCSD

This event is fired when the desired types of events have occured. Will have a list of 'ChangeStreamDocuments' that was received as input.

Declaration

public event Action<IEnumerable<ChangeStreamDocument<T>>> OnChangesCSD

Event Type

Type	Description
Action<IEnumerable<ChangeStreamDocument<T>>>

OnChangesCSDAsync

This event is fired when the desired types of events have occured. Will have a list of 'ChangeStreamDocuments' that was received as input.

Declaration

public event AsyncEventHandler<IEnumerable<ChangeStreamDocument<T>>> OnChangesCSDAsync

Event Type

Type	Description
AsyncEventHandler<IEnumerable<ChangeStreamDocument<T>>>

OnError

This event is fired when an exception is thrown in the change-stream.

Declaration

public event Action<Exception> OnError

Event Type

Type	Description
Action<Exception>

OnStop

This event is fired when the internal cursor get closed due to an 'invalidate' event or cancellation is requested via the cancellation token.

Declaration

public event Action OnStop

Event Type

Type	Description
Action