Which is the safest way to talk to SharePoint servers of different versions?

I need to upload, download and manage files in SharePoint and there are many ways to talk 开发者_开发技巧to a SharePoint server, but what is the best one to choose to support different versions of SharePoint (2003, 2007, 2010...)?

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"Safe" is good, especially when you are talking about 2007, 2010 and 2003. The Sharepoint Architecture was fundamentally changed throughout the years and I don't know of anything which didn't changed with the different versions.

• WebDAV: Impossible to work with - Sharepoint actually implements its own WebDAV Protocol and not the standardized one. I'm not sure whether it changed throughout the years. But: All Sharepoint Versions included some kind of WebDAV, so it might be possible to leverage that.

• WebService: They're all different between the versions

• FrontPage RPC: UGH... No.

• Client OM: Is new in 2010.

• Custom WCF Service: Yes. Same goes for third party ADO.NET Connectors - leveraging the same functionality - Custom development.

The "safest" way as in standardized I would say are the webservices. You will still need to account for the different Sharepoint versions, but all of them had webservices. My second approach would be to code a custom WCF service, querying the object model - or use ADO.NET Connectors from third parties.