We have a SharePoint 2010 portal running and now we decided to integrate with the existing ERP application. It works like there is a Request generate through SharePoint 2010 custom form and then a NINTEX workflow product takes approvals and finaly send the approved data with request details to ERP...then in next stage INVOICE generates in ERP based on Request and comes to SharePoint invoice custom list library for further workflow processing and write back to ERP.
I designed this as the following
Purchase Request (OUT from SharePoint)
SharePoint (Form) -----> [ WebService ] ------> ERP
Purchase Invoice (IN to SharePoint from ERP)
SharePoint (Custom List) <---------------- [ WebService ] <----------------- ERP
I know client object model and how to read/write into list but just don't know how to create a SECURE webservice which access SharePoint environment so it can write back into lists and not every tom dick and harry can access webservice and send parcels ...the webservice should be accessible in a secure way.
What is the industry standard to write such secure services to integrate with SharePoint and other 3rd party products. Is it some kind of WCF based service or SharePoint webservice..or what...would appreciate the guidance.