How to replicate full-trust solutions in SharePoint Online

Question

I have a question concerning SharePoint Online customization :

Full trust solutions allow developer to customize almost everything on SharePoint On-premise. Is it possible to replicate the functionality of full-trust solutions for SharePoint Server in SharePoint Online?

Answer 1

It does depend on what you are doing, but, generally, you would adopt the SharePoint add-in model. You would create a provider hosted SharePoint add-in and give it full tenant-scoped permissions. The app will then be able to make app-only calls to SharePoint with full control over everything. Your full-trust solution for SharePoint Server would have to be re-written to use CSOM (Client-Side Object Model), since SharePoint Online does not support SSOM (Server-Side Object Model). Note that not everything in SSOM is supported in CSOM.

Further references:

https://channel9.msdn.com/Series/Reimagine-SharePoint-Development/Understanding-the-differences-between-Server-Side-Object-Model-and-the-Client-Side-Object-Model

https://dev.office.com/sharepoint/docs/sp-add-ins/get-started-creating-provider-hosted-sharepoint-add-ins