Microsoft Dynamics AX 2012 Services and (Application Integration Framework) AIF architecture

Hi there!

In this post I would like to discuss, in detail, the Application Integration Framework (AIF) and its capability to integrate Microsoft Dynamics AX 2012 with other systems inside and outside an organization.


So what is the AIF and why is important?


The AIF provides capability to integrate Microsoft Dynamics AX 2012 with other systems inside and outside an organization by enabling the exchange of data through XML.


This formatted XML is referred to as a document, and each document contains data and business logic. Documents are based on a document class and defined by using Microsoft Dynamics AX.


Further, AX 2012 ships together with standard document services that support common business processes. As in AX 2009, in AX 2012 we can also customize existing services or create our services.

How documents are exchanged?

The AIF provides an extensible framework for the exchange of XML documents with external systems. The framework supports both synchronous and asynchronous transports.

In synchronous mode, requests are tightly coupled to responses, which means that the submitter of the request must wait for a response from AIF before proceeding.  In this case, AIF does process the request immediately and then sends a response.

In asynchronous mode, however, requests are placed into a queue, called the gateway queue. Queued messages are processed at a later time and AIF sends a response when processing is completed. In this case, responses are delayed, but note that large volumes of messages can be processed more efficiently, and message processing can be controlled by changing various configuration settings. Further, the AIF can be used to send and retrieve data into/from AX.


Inbound / Outbound Exchanges

Inbound exchange, an external system may send a sales order so that the sales order can be saved to the Microsoft Dynamics AX database.
 
Outbound exchange, an external system may send a request for a purchase order and receive the purchase order.

The inbound and outbound exchanges can be categorized in the following ways:

• Send data – AX sends documents to an external system.
• Send data in response to requests – AX receives requests for documents from another authorized system, and retrieves the requested information, such as a document or a list of documents, from the AX database. Then AX returns the information to the requesting system.
• Receive and create data – AX receives documents from another authorized system and creates new records in the Microsoft Dynamics AX database.

AIF Architecture

AX 2012 exposes its functionality through services that are based on Windows Communication Foundation (WCF) and hosted on Application Object Server (AOS).

External applications and client applications on the local area network consume AX services by accessing them directly from AOS. These clients and applications include AX components such as the AX client, Office Add-, and Enterprise Portal.

The following diagram illustrates the services and AIF architecture.





Application Integration Framework Process

• Internet-based external applications and clients access the AX services through Internet Information Services (IIS).
• IIS routes the incoming requests for AX services to AOS. All services requests, regardless of their origin, are handled by the WCF runtime that is hosted on AOS.
• The AIF request pre-processor, if it is configured, can intercept the inbound request messages for custom preprocessing, such as message transforms or value substitutions.
• The AX service invokes the necessary business logic to process the inbound request message.
• Similarly, the AIF response post-processor, if it is configured, can intercept the outbound response messages for custom post-processing, such as message transforms or value substitutions.
• The AIF response post-processor then returns the response to the client.

NOTE:  Microsoft Dynamics AX 2012 no longer includes a BizTalk adapter. For more information about how to use Microsoft BizTalk Server together with Microsoft Dynamics AX 2012, see Exchanging documents between BizTalk Server and AIF.


Services in AX 2012

Application Object Server (AOS) is the Windows Communication Foundation (WCF) service host for Microsoft Dynamics AX 2012 services that are exposed to users and applications on an intranet.

• To consume services over the Internet, you must host services on Internet Information Services (IIS).
• Services that are hosted on IIS use the WCF message routing service. IIS routes all service requests to AOS.
• All service requests are processed on AOS, regardless of whether they originate on the Internet or an intranet. AOS then returns a response to the service consumer via IIS.
• Exchanges that are configured to use Web services are processed synchronously and therefore are not queued.
• AX deploys the service that is based on Web Services Description Language (WSDL) to a subfolder of the virtual directory that is associated with the Web site that you provide.

NOTE: In general when dealing with the AIF, keep in mind that the AIF user names and passwords are encrypted in the Application.Host configuration file located in C:\Windows\System32\Inetsrv\Config. Therefore, DO NOT copy files from other environments into this location when the AIF and/or Workflow are running in the same machine.


AX 2012 supports the following three kinds of services:

• Document services are query-based services that can be used to exchange data with external systems by sending and receiving XML documents. These documents represent business entities, such as customers, vendors, or sales orders.
• Custom services can be used by developers to expose any X++ logic, such as X++ classes and their members, through a service interface.
• System services are provided by Microsoft Dynamics AX. System services include the Query service, the Metadata service, and the User Session service.

Further, system services are not customizable, and they are not mapped to any query or X++ code. For more information about system services, see AIF System Services.


Integration ports in AX 2012

In Microsoft Dynamics AX 2012, integration ports provide simplified administration of services and Application Integration Framework (AIF). Integration ports replace the AIF endpoints and related concepts that were used in previous releases of Microsoft Dynamics AX.

• Each integration port can expose one or more services, and each integration port has a unique Uniform Resource Identifier (URI) that identifies the address of the port.
• Each integration port also has a direction. An integration port can be either an inbound integration port or an outbound integration port.
• An inbound integration port is a destination for messages that originate from outside Microsoft Dynamics AX.
• An outbound integration port is a destination for messages that originate from your Microsoft Dynamics AX system. Inbound integration ports can be one of two types: basic or enhanced. Outbound integration ports are always enhanced ports.

Basic integration ports

Basic integration ports are exposed at a specific Windows Communication Foundation (WCF) endpoint on the Application Object Server (AOS) host. Only a developer can create a new basic integration port.
 

Enhanced integration ports

If you want advanced integration capabilities that you can use to customize the behavior of an integration port, you must create an enhanced integration port.

Enhanced integration ports provide the following capabilities that basic integration ports do not provide:

• A variety of protocols are supported through WCF adapters. These protocols include HTTP, NetTCP, and Message Queuing, which is also known as MSMQ.
• Enhanced integration ports also support a file system adapter that lets you use file paths as addresses.
• You can perform pre-processing and post-processing of service requests and service responses.
• You can create customizations for data contracts by specifying service operations and policies for document data.
• You can specify advanced security and troubleshooting settings.

Adapters

In AX 2012 services and AIF, integration ports use adapters. These adapters enable AX to communicate by using various transport protocols.

AX 2012 provides the following four adapters that represent predefined bindings:

HTTP adapter – This adapter provides for synchronous message exchanges by using an HTTP or HTTPs transport.

NetTCP adapter – This adapter provides for synchronous exchanges by using WS-* standards support over the Transmission Control Protocol (TCP) transport.

This adapter corresponds to the WCF-NetTcp binding in Windows Communication Foundation (WCF).

MSMQ adapter – This adapter provides support for queuing by using Message Queuing as a transport. Message Queuing is also known as MSMQ.

Message Queuing is a type of asynchronous communication. This adapter corresponds to the WCF-NetMsmq binding in WCF.

File system adapter – This adapter provides support for the asynchronous exchange of documents through file system directories.


Messages and transforms in AIF

In AX 2012 services and AIF, a message corresponds to a Windows Communication Foundation (WCF) message. A message is a self-contained unit of data that can consist of several parts. These parts include a body and headers. When AIF receives and processes an inbound message, it generates an outbound message in response.

Although AIF supports the transfer of data in any arbitrary format, most information exchanges with AIF services use XML documents.

In order to create an XML document that adheres to a standard for a particular exchange of information, AIF requires XML documents to follow an XML style definition (XSD). XSD files (which have a .xsd file name extension) are meta-documents that describe the format, or schema, of XML documents that declare the namespace of the XSD.

Each schema includes rules about the hierarchical arrangement of XML elements, which elements must be present in the document, and other such requirements.


Schemas

1-Document service schemas: Each document service has a unique schema that describes the fields that can be added, read, updated, and so forth, by using the particular document service.

2-Message schema: Asynchronous exchanges require XML messages to be contained by the AIF message envelope. The namespace for the message schema is:
http://schemas.microsoft.com/dynamics/2011/01/documents/Message

3-Message-set schema: AIF uses the message-set, or batch, schema to contain batched AIF messages in asynchronous exchanges. The namespace for the message-set schema is:

http://schemas.microsoft.com/dynamics/2009/06/documents/Batch

4-Entity key schemas: AIF uses entity key schemas to contain name-value pairs, such as those used to query for a particular item during a read operation or when sending a response to a create operation. The namespaces for entity keys and entity key lists are:

http://schemas.microsoft.com/dynamics/2006/02/documents/EntityKey
http://schemas.microsoft.com/dynamics/2006/02/documents/EntityKeyList

5-Shared types schema: AIF aggregates common property types in the shared-types schema. The namespace for the shared-types schema is:

http://schemas.microsoft.com/dynamics/2008/01/sharedtypes

6-Fault schema: AIF uses the fault schema to contain response messages about error conditions. The namespace for the fault schema is:

http://schemas.microsoft.com/dynamics/2008/01/documents/Fault


Schema locations

You can save XSDs for particular document services, including their imported schemas (such as the shared-types schema) and any port-specific customizations, when you configure data policies for an integration port.

You can retrieve XSDs for common schemas from the following directory where you installed Microsoft Dynamics AX:
Program files\Microsoft Dynamics AX\60\Server\MicrosoftDynamicsAX\bin\Application\Share\Include


Processing messages

When you use an enhanced integration port for services and AIF, you can perform custom processing of data, such as XML documents, as each message passes through the integration port. Enhanced integration ports use the following two concepts to process messages during inbound or outbound exchanges:

• Extensible Stylesheet Language Transformations (XSLT)
• .NET-based transforms to messages.

In addition, transforms are run for inbound exchanges before they are run for outbound exchanges. Transforms process the whole message. Headers are included in the processing.

NOTE: Transforms apply only to asynchronous exchanges.

.Net-based transforms can convert messages to or from any proprietary format. AX services and AIF can process XML documents only if the documents comply with the service XSD.

If an incoming document is based on XML but uses a different schema, you can use Extensible Stylesheet Language (XSL) to transform the document to the AIF schema.

If an incoming document is not based on XML, such as a comma-delimited file, you can use a .NET Framework assembly to convert the file to the AIF schema.
Pipelines use components to enable the processing of requests for service operations. These components include custom components that are written in X++ code.

For example, if an inbound message contains customer records, your AIF pipeline can contain an XSLT component that updates an element in the XML, based on the value of the customer status element.

Further, your AIF pipeline can contain one or more of any available transformation component. Alternatively, your AIF pipeline can contain no transformation components.

Processing that occurs in pipelines, including XML transformation, applies to both synchronous and asynchronous exchanges.

For inbound exchanges, pipelines are run after transforms. For outbound exchanges, pipelines are run before transforms.

The following diagram shows how data moves through an enhanced inbound integration port.




That's all for now.