The events framework allows the transmission of messages from Process to Process, from Email to Process, or from an external application to a running process or an active event. The various properties of these messages are configured using a custom version of an XML configuration file called message-types.xml. Your custom version of this file should be take a custom name such as message-types-custom.xml and be stored in the <APPIAN_HOME>/deployment/web.war/WEB-INF/conf/process directory.

Your custom version of this file should include the elements and attributes listed in the following snippet.

 message-types-custom.xml
 <?xml version="1.0" encoding="ISO-8859-1" ?>
   <messageTypes>
     <messageType id="0">
       <name>Process to Process</name>
       <processesCanProduce>true</processesCanProduce>
       <properties>
         <property name="EventType">
           <type>3</type>
           <multiple>false</multiple>
           <required>true</required>
           <inputFromModeler>false</inputFromModeler>
         </property>
       </properties>
     </messageType>
   </messageTypes>

The following table provides descriptions for the various XML tags in this file:

Name	Description
messageTypes	This tag wraps the messageType elements.
messageType	Contains the configuration for one message type. The ID attribute is how the message type is referenced in <APPIAN_HOME>/deployment/web.war/WEB-INF/conf/process/jms-topics.xml. 0,1, and 2 are reserved.
name	The name of the message type.
processesCanProduce	Whether Send Message events in Process can send this type of message.
properties	This tag wraps the properties for the message type.
property	Contains the configuration for one message property. The name attribute is the name of the attribute (also how you refer to it in expressions). The name should only consist of numbers, letters, and underscores, and should not start with a number.
type	The TypedVariable type (same type codes as ACPs).
multiple	Whether the property can contain multiple values.
required	Whether the property is required (and guaranteed to be populated).
inputFromModeler	Whether the property can be set in the Send Message mappings grid.
visibleOnReceiveMessage	Whether the property is visible on the Receive Message event (in dropdown lists and in the Expression Editor).

• List the ID attribute defined for your custom message type in a custom version of <APPIAN_HOME>/deployment/web.war/WEB-INF/conf/process/jms-topics.xml.