The /v1/calendar Rest API, available as of Platform 4.2, is considered Experimental. It is the new substitute of the deprecated /cs/calendar Rest API.
Check the references at REST API Documentation 4.2.
The Calendar Rest API meets the common requirements of new eXo Platform Rest services. Here are some tips that help you quickly get familiar with the service:
A good way to try the service is using a web browser with plugins for REST and JSON. For example with Chrome, you can install Advanced Rest Client and JSON Formatter extensions.
Use the URL
While you can also use /portal/rest/v1/calendar, notice that the context /rest is designed for secure accesses to the Rest services, so it is recommended.
CRUD operations: There are four verbs used for CRUD operations: GET, POST (for Create), PUT (for Update) and DELETE.
All methods consistently use JSON to transfer data in requests/reponses.
Query limit: A GET method can query a single item or a collection. In case of collection, there is a query limit on the server side that limits the number of items returned. This is configurable for effective performance.
Queries for Events, Tasks and Occurrences always have finite time parameters. By default the time range is one week from the current server time.