AS4 Messaging Standard

AS4 is a recent B2B messaging standard. It can exchange any type of payloads (XML, JSON, Binary, ect.) and also it supports sending multiple payloads in one AS4 message.

AS4 originates from ebXML (Electronic Business XML). AS4 Profile of ebMS 3.0 which is a conformance profile of AS4 defines the following 3 conformance profiles (CP) defining subsets of ebMS V3 options to be supported by an AS4 Message Service Handler (MSH).

• AS4 ebHandler CP
• AS4 Light Client CP
• AS4 Minimal Client CP

AS4 Messaging Model

AS4 defines a Four-Corner-Model including the components involved in a message exchange. Following are the entities of this four-corner-model.

Message Producer: Business application which sends the message content to the sending Message Service Handler(MSH).

Sending Message Service Handler: Packages the message content and sends to the intended receiving MSH.

Receiving Message Service Handler: Receive the message from the sending MSH.

Message Consumer: The business application which receives the message content from receiving MSH.

The above-mentioned conformance profiles of AS4 Profile of ebMS 3.0 defines supported different subsets of AS4 profile options by an AS4 Message Service Handler.

• The message sent from the producer to the sending MSH can be of any format agreed by those two entities.
• Similarly, the messages exchanged between the receiving MSH and the consumer can be of any format.
• AS4 defines the message format being exchanged between the sending MSH and receiving MSH.
• Apart from that AS4 P-mode configuration files which reside in the MSHs instruct on how to handle AS4 messages.

AS4 Message Exchange Patters (MEPs)

In AS4, there are two message exchange patterns. 

• One-way / Push
• In one-way / push MEP, the sending MSH sends the AS4 user message containing payloads to the receiving MSH. The initiator is the sending MSH.
• One-way / Pull
• In one-way / pull MEP, the receiving MSH sends a pull request signal message to the sending MSH. Then the sending MSH sends the user message. The initiator in this MEP is the receiving MSH.

AS4 Minimal Client Profile

As per the specification AS4 minimal client profile applies only to one side of an MEP (acting as a “client” to the other party).

P-Mode configuration file for AS4 Minimal Client Profile

      push
      http://wso2.org/examples/agreement0
      http://www.oasis-open.org/committees/ebxml-msg/one-way
      http://www.oasis-open.org/committees/ebxml-msg/push
      
           org:wso2:example:company:A
           Sender
      
      
           org:wso2:example:company:B
           Receiver
      
      
           

http://localhost:8280/as4Test
1.2
      
      
           Examples
           StoreMessage
      
      
           
                true
                true