Mohit Mehral
We are all aware that Liferay Portal can connect to external
repositories like alfresco,sharepoint and other CMS using CMIS atompub.
Is there any way we can connect to Liferay portal repository from
another liferay instance.?
Out of the box: No. But the "store" interface for Liferay's document library is pretty narrow and you could implement your own store based on the existing example implementations, and have it interface with that other instance's API. You'll have to make some assumptions about application of permissions on the remote system, as both aren't guaranteed to feature the same user accounts.
And you might want to look at the new "headless Liferay" features when implementing that Store. I admit to not having worked with it yet, but it's supposed to give a more relevant API to Liferay's core data.
