EPiServer CMS 5 SP1
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This technical note contains functional and technical information for the EPiServer Events System in EPiServer CMS 5 Service Pack 1. For details of the EPiServer Events System in EPiServer CMS 5 R1 before Service Pack 1 see this tech-note.
The system provides a mechanism for distributing events within an EPiServer CMS 5 site, between EPiServer CMS 5 sites on the same physical server (enterprise), and between EPiServer CMS 5 sites on separate servers (load-balanced standard and enterprise).
The system is based on Microsoft Windows Communication Foundation (“Indigo”) technology as this provides for object-oriented interface definitions and configurable interprocess communication methods, without the need to change code.
The EPiServer.Events.Clients.Event class is the public API of the EPiServer CMS 5 Events System. It allows for the sending and receiving of site events in a de-coupled manner. The Events System does not have any pre-defined events when EPiServer CMS starts. It is up to the code that wants to send and receive events to register them using the Event.GetEvent static method. The GetEvent method accepts a GUID event Id and will create a new Event object instance if one hasn't already been created for the event Id, otherwise it will return the existing one. It is important to note that the GUID event Id is only important to users of the Events System in that it allows different pieces of code to identify the same event. The Events System has no knowledge of what these events are or who uses them.
The Event class has two .NET events that user code can subscribe to, the Raised event and the Missed event. The Raised event is fired when some code has called the Raise method of the Event class. The Missed event is fired when the Event System detects that a remote event (an event received from another site or server) has gone missing. The algorithm for detecting a missing event is based upon tracking the sequence numbers allocated to remote events and detecting after a predetermind amount of time that one or more are missing.
The following text describes the logical setup and execution of the events systems.
The EPiServer Events System is used to distribute events with an EPiServer CMS 5 site and between sites in an enterprise and/or load balanced scenario. See the Configuring EPiServer Enterprise Edition technote for information about installing and configuring load balanced and enterprise sites.
To configure the EPiServer Events System, make the following checks/adjustments to the EPiServer CMS 5 web.config file on all affected servers:
<siteSettings enableEvents="true" enableRemoteEvents="true">
<add name="udpTransport" type="Microsoft.ServiceModel.Samples.UdpTransportElement, EPiServer.Implementation" />
<!-- Before deployment, you should remove the returnFaults behavior configuration to avoid disclosing information in exception messages -->
<service name="EPiServer.Events.Remote.EventReplication" behaviorConfiguration="DebugServiceBehaviour">
<endpoint name="RemoteEventServiceEndPoint" contract="EPiServer.Events.ServiceModel.IEventReplication" binding="customBinding" bindingConfiguration="RemoteEventsBinding" address="soap.udp://184.108.40.206:5000/RemoteEventService" />
<endpoint name="RemoteEventServiceClientEndPoint" address="soap.udp://220.127.116.11:5000/RemoteEventService" binding="customBinding" bindingConfiguration="RemoteEventsBinding" contract="EPiServer.Events.ServiceModel.IEventReplication" />
<serviceDebug includeExceptionDetailInFaults="true" />
<udpTransport multicast="True" />
Examples of the EPiServer CMS 5 functionality that uses the Events System are:
To test page cache events, edit a page on one EPiServer CMS 5 site and ensure the change is reflected (with 2/3 seconds) on the 2nd load balanced EPiServer CMS 5 site. See below for exact details:
To test permanent link map store events, create or edit a link on a page on one EPiServer CMS site and ensure the change is reflected (with 2/3 seconds) on the 2nd load balanced EPiServer CMS site. See below for exact details:
EPiServerRemoteEventsListener is a diagnostics application for the EPiServer CMS 5 Events System.
EPiServer CMS 5 uses Windows Communication Foundation technology to send events between load balanced sites. The EPiServerRemoteEventsListener application listens on the same UDP channel as EPiServer CMS in order to display the events that are being transmitted by EPiServer CMS both on the local server and by other servers on the same network. This can be useful to determine if firewalls or other software is blocking the EPiServer events.
The application can also be used to send events. It can be useful to run an instance in send mode on one server and one in receive (normal) mode on another server to test if the necessary ports are open that EPiServer Events uses. To launch in send mode start the application with a command line parameter of 'send'
The application requires .NET 2.0 and can be installed using a simple XCopy of the contents of the zip file.
If the Events System doesn't appear to be working properly then check the following items: