Comet modes

Data streaming and long polling Comet modes are supported. The client can decide at run time which mode to use depending on which mode works best with the particular technology stack or network topology.

Note: For key based notifications, the client should request the latest data from the master data source to ensure that the client does not hold stale data due to missed notifications.

Data streaming: When the client requests information from the server, the server holds the request indefinitely. As information becomes available to the server, it is pushed to the client by writing it to the output stream of the response continuously.; Data streaming is recommended and used by default if a mode is not specified by the client. Data streaming cannot be used if there is a proxy server between the client and push redirector that does not handle uncommitted server responses for each request and response. If data streaming is not appropriate, the client must request the long polling mode when the client establishes the initial Comet connection.
Long polling: When the client requests information from the server, the server holds the request until a notification is ready to be pushed to the client. After information becomes available to the server, a completed response is pushed to the client and the connection closes. The client immediately registers for push notifications again in order to continue receiving updates.