This guide describes how to develop and deploy Microsoft Silverlight applications using Universal Messaging, and assumes you already have Universal Messaging installed.

Please refer to the Universal Messaging C# Developer's Guide for more information on developing Silverlight clients.

When creating a Silverlight application, it is worth remembering to correctly set the ACLs for both the realm(s) and channel(s) used, to ensure that the application is able to access the Universal Messaging server. This can easily be performed using the Enterprise Manager.

When deploying a Silverlight application on a different host to the Universal Messaging server, Silverlight requires the use of a client access policy file to validate that the connection is permitted. For example :

When Silverlight detects a connect attempt outside of the host from which the application was downloaded, it makes a request for the policy file from the host you are making the connection to. When using an nhp (HTTP) or nhps (HTTPS) RNAME to connect to the Universal Messaging realm, Silverlight makes a GET request for a clientaccesspolicy.xml file from the root of the web server (in this case, the file plugin running on the Universal Messaging server HTTP or HTTPS interface). If no clientaccesspolicy.xml is found, it then makes a second GET for a crossdomain.xml file, again from the root of the file plugin.

An example of a clientaccesspolicy.xml file for Silverlight clients is shown below. This example should not be used for anything other than testing purposes, as it essentially allows open access to and from all domains. For more information on cross domain access with Silverlight, and configuring the clientaccesspolicy.xml file, see the Microsoft MSDN guide.