LSClientDelegate Protocol Reference

Conforms to NSObject
Declared in LSClientDelegate.h

Overview

Protocol to be implemented to receive LSLightstreamerClient events comprehending notifications of connection activity and errors.

Events for these delegates are dispatched by a different thread than the one that generates them. This means that, upon reception of an event, it is possible that the internal state of the client has changed. On the other hand, all the notifications for a single LSLightstreamerClient, including notifications to LSClientDelegate, LSSubscriptionDelegate and LSClientMessageDelegate, will be dispatched by the same thread.

– clientDidRemoveDelegate:

Event handler that receives a notification when the LSClientDelegate instance is removed from a LSLightstreamerClient through [LSLightstreamerClient removeDelegate:].

This is the last event to be fired on the delegate.

- (void)clientDidRemoveDelegate:(nonnull LSLightstreamerClient *)client

Parameters

client

The LSLightstreamerClient this instance was removed from.

Declared In

LSClientDelegate.h

– clientDidAddDelegate:

Event handler that receives a notification when the LSClientDelegate instance is added to a LSLightstreamerClient through [LSLightstreamerClient addDelegate:].

This is the first event to be fired on the delegate.

- (void)clientDidAddDelegate:(nonnull LSLightstreamerClient *)client

Parameters

client

The LSLightstreamerClient this instance was added to.

Declared In

LSClientDelegate.h

– client:didReceiveServerError:withMessage:

Event handler that is called when the Server notifies a refusal on the client attempt to open a new connection or the interruption of a streaming connection.

In both cases, the client:didChangeStatus: event handler has already been invoked with a DISCONNECTED status and no recovery attempt has been performed. By setting a custom handler, however, it is possible to override this and perform custom recovery actions.

The error code can be one of the following:

  • 1 - user/password check failed

  • 2 - requested Adapter Set not available

  • 7 - licensed maximum number of sessions reached (this can only happen with some licenses)

  • 8 - configured maximum number of sessions reached

  • 9 - configured maximum server load reached

  • 10 - new sessions temporarily blocked

  • 11 - streaming is not available because of Server license restrictions (this can only happen with special licenses)

  • 30-41 - the current connection or the whole session has been closed by external agents; the possible cause may be:

  • The session was closed by the administrator, through JMX (32) or through a “destroy” request (31);

  • The Metadata Adapter imposes limits on the overall open sessions for the current user and has requested the closure of the current session upon opening of a new session for the same user on a different browser window (35);

  • An unexpected error occurred on the Server while the session was in activity (33, 34);

  • An unknown or unexpected cause; any code different from the ones identified in the above cases could be issued. A detailed description for the specific cause is currently not supplied (i.e. errorMessage is nil in this case).

  • 60 - this kind of client is not allowed by the current license terms.

  • 61 - there was an error in the parsing of the server response thus the client cannot continue with the current session.

  • 66 - an unexpected exception was thrown by the Metadata Adapter while authorizing the connection.

  • 68 - the Server could not open or continue with the session because of an internal error.

  • <= 0 - the Metadata Adapter has refused the user connection; the code value is dependent on the specific Metadata Adapter implementation

- (void)client:(nonnull LSLightstreamerClient *)client didReceiveServerError:(NSInteger)errorCode withMessage:(nonnull NSString *)errorMessage

Parameters

client

The LSLightstreamerClient instance.

errorCode

The error code.

errorMessage

The description of the error as sent by the Server.

Declared In

LSClientDelegate.h

– client:didChangeStatus:

Event handler that receives a notification each time the LSLightstreamerClient status has changed.

The status changes may be originated either by custom actions (e.g. by calling [LSLightstreamerClient disconnect]) or by internal actions. The normal cases are the following:

  • After issuing [LSLightstreamerClient connect], if the current status is DISCONNECTED*, the client will switch to CONNECTING first and to CONNECTED:STREAM-SENSING as soon as the pre-flight request receives its answer. As soon as the new session is established, it will switch to CONNECTED:WS-STREAMING if the environment permits WebSockets; otherwise it will switch to CONNECTED:HTTP-STREAMING if the environment permits streaming or to CONNECTED:HTTP-POLLING as a last resort. On the other hand if the status is already CONNECTED:* a switch to CONNECTING is usually not needed.

  • After issuing [LSLightstreamerClient disconnect], the status will switch to DISCONNECTED.

  • In case of a server connection refusal, the status may switch from CONNECTING directly to DISCONNECTED. After that, the client:didReceiveServerError:withMessage: event handler will be invoked.

Possible special cases are the following:

  • In case of Server unavailability during streaming, the status may switch from CONNECTED:*-STREAMING to STALLED (see [LSConnectionOptions stalledTimeout]). If the unavailability ceases, the status will switch back to CONNECTED:*-STREAMING; otherwise, if the unavailability persists (see [LSConnectionOptions reconnectTimeout]), the status will switch to CONNECTING and eventually to CONNECTED:*-STREAMING.

  • In case the connection or the whole session is forcibly closed by the Server, the status may switch from CONNECTED:*-STREAMING or CONNECTED:*-POLLING directly to DISCONNECTED. After that, the client:didReceiveServerError:withMessage: event handler will be invoked.

  • Depending on the setting in [LSConnectionOptions slowingEnabled], in case of slow update processing, the status may switch from CONNECTED:WS-STREAMING to CONNECTED:WS-POLLING or from CONNECTED:HTTP-STREAMING to CONNECTED:HTTP-POLLING.

  • If the status is CONNECTED:*POLLING and any problem during an intermediate poll occurs, the status may switch to CONNECTING and eventually to CONNECTED:POLLING. The same holds for the CONNECTED:STREAMING case, when a rebind is needed.

  • In case a forced transport was set through [LSConnectionOptions forcedTransport], only the related final status or statuses are possible.

  • In case of connection problems the status may switch from any value to DISCONNECTED:WILL-RETRY (see [LSConnectionOptions retryDelay]).

By setting a custom handler it is possible to perform actions related to connection and disconnection occurrences. Note that [LSLightstreamerClient connect] and [LSLightstreamerClient disconnect], as any other method, can be issued directly from within a handler.

- (void)client:(nonnull LSLightstreamerClient *)client didChangeStatus:(nonnull NSString *)status

Parameters

client

The LSLightstreamerClient instance.

status

The new status.

Declared In

LSClientDelegate.h

– client:didChangeProperty:

Event handler that receives a notification each time the value of a property of [LSLightstreamerClient connectionDetails] or is changed.

Properties of these objects can be modified by direct calls to them or by server sent events. Possible property names are the following:

  • adapterSet

  • serverAddress

  • user

  • password

  • serverInstanceAddress

  • serverSocketName

  • clientIp

  • sessionId

  • contentLength

  • idleTimeout

  • keepaliveInterval

  • requestedMaxBandwidth

  • realMaxBandwidth

  • pollingInterval

  • reconnectTimeout

  • stalledTimeout

  • connectTimeout

  • currentConnectTimeout

  • retryDelay

  • firstRetryMaxDelay

  • slowingEnabled

  • forcedTransport

  • serverInstanceAddressIgnored

  • reverseHeartbeatInterval

  • earlyWSOpenEnabled

  • HTTPExtraHeaders

  • HTTPExtraHeadersOnSessionCreationOnly

- (void)client:(nonnull LSLightstreamerClient *)client didChangeProperty:(nonnull NSString *)property

Parameters

client

The LSLightstreamerClient instance.

property

The name of the changed property.

Declared In

LSClientDelegate.h

– client:willSendRequestForAuthenticationChallenge:

Event handler that receives a notificaiton each time the underlying connection is going to request authentication for a challenge in order to proceed.

If the delegate implements this method, the connection will suspend until challenge.sender is called with one of the following methods:

  • useCredential:forAuthenticationChallenge:,

  • continueWithoutCredentialForAuthenticationChallenge:,

  • cancelAuthenticationChallenge:,

  • performDefaultHandlingForAuthenticationChallenge: or

  • rejectProtectionSpaceAndContinueWithChallenge:.

If not implemented, the default behavior will call performDefaultHandlingForAuthenticationChallenge:.

Note that if more than one delegate is added to the same client, only the first one implementing this method will be notified of this event.

Note also that this notification is called directly from the network thread. The method implementation should be fast and nonblocking. Any slow operations should have been performed in advance.

- (void)client:(nonnull LSLightstreamerClient *)client willSendRequestForAuthenticationChallenge:(nonnull NSURLAuthenticationChallenge *)challenge

Parameters

client

The LSLightstreamerClient instance.

challenge

The challenge that the client must authenticate in order to proceed with its request.

Declared In

LSClientDelegate.h