SharePoint Add-in Recipe - Custom Actions
csom, custom actions, list item menus, Office 365 PnP, ribbon, SharePoint add-ins, SharePoint REST API
The approach you take to modify list item menus and the ribbon in SharePoint is different in the new SharePoint Add-in model than it was with Full Trust Code. In a typical Full Trust Code (FTC) / Farm Solution scenario, list item menus and ribbon modifications were defined in XML (custom actions), packaged in features, and deployed via SharePoint Solutions.
In an SharePoint Add-in model scenario, you use the SharePoint Client-side Object Model (CSOM) or REST API to create custom actions that modify list item menus and the ribbon. This pattern is commonly referred to as the remote provisioning pattern.
You can read the rest of this Office 365 Patterns and Practices Guidance article on GitHub, here: https://github.com/OfficeDev/PnP-Guidance/blob/master/articles/SharePoint-Add-In-Recipe-custom-actions.md