If you currently using legacy APIs in Exchange 2007 (CDOEX, WEBDAV, Event Sinks or Exchange OLEDB) for integration to LOB or 3rd party ISV applications, you can now try Exchange Web Services. Comparison between legacy APIs to EWS is explained here, including the Exchange 2007 Legacy API property mapping, for your migration purpose.
LOB apps that use EWS can access data store items locally or remotely by using a SOAP version 1.1 (or 1.2). EWS is deployed with client access server role. Exchange Server 2007 clients connect to the server that is running Exchange 2007 that has the Client Access server role installed in an Active Directory directory service site by using an HTTPS connection. The target Client Access server obtains the information by communicating over MAPI to the Exchange server that has the Mailbox server role installed and then sends it back to the source Client Access server. If the target mailbox is in the same Active Directory site, the Client Access server uses MAPI to communicate with the Mailbox server to obtain the information. The Client Access server then provides the data back to the client.
How It Works
When a client application requests information from the Exchange store, an XML request message that complies with the SOAP standard is created and sent to the Exchange server. When the Microsoft Exchange server receives the request, it verifies the credentials that are provided by the client and automatically parses the XML for the requested data. The server then builds a SOAP response that contains XML data that represents the requested strongly typed objects and their properties. The XML data is sent back to the client application in an HTTP response. The client application then de-serializes the XML and uses the data to reform the strongly typed objects. You can read more on about EWS architecture from here as you have to understand some additional concepts like autodiscover service, event notification, delegate access and server-to-server authorization.
What in Exchange Web Services
EWS provides the functionality to enable client applications to communicate with the Exchange server. EWS provides access to much of the same data made available through Outlook, to enable LOB applications to have functionalities like Outlook. The Exchange Web Services clients can integrate Outlook data into Line-of-Business (LOB) applications. Exchange Web Services is described by three files that are located in the EWS virtual directory:
- Services.wsdl : contract between client and server.
- Messages.xsd : request and response SOAP messages.
- Types.xsd : elements used in the SOAP messages.
Exchange Web Services provides the following types of operations:
- Availability
- Messaging Records Management
- Folder
- Item
- Utility
- Notification
- Synchronization
How to Start
You can download TechReady 2007 EWS Sample Codes to get started with EWS. Extract the installer then open EWSDemos.sln using Visual Studio 2005/2008. It will be better to use VS 2008 and .NET 3.5 as you can utilize new features like LINQ in your codes. To change the target WS from contoso.com, you can delete the existing WS proxy and add the new proxy based on your configuration.
Then you can start to explore the following demo applications:
- Auto Discovery Demo
- Availability Demo
- Create Meeting and Send Invitation Demo
- Pull Notification Demo
Hope this helps!
Cheers – RAM