Get item by it's guid using rest

Hello everyone,

for a solution i build for SharePoint 2013 i need to find a specific file using it's guid.

the szenario is, that i get information about files in sharepoint and save its guid in another system.

later then, i have to find the file knowing only its guid and its parent web.

so i need a REST pendant for web.getFileById

is there a way?

thanks in advance

Dennis