once

The once record mode will:

• Replay previously recorded interactions.
• Record new interactions if there is no cassette file.
• Cause an error to be raised for new requests if there is a cassette file.

It is similar to the new_episodes record mode, but will prevent new, unexpected requests from being made (i.e. because the request URI changed or whatever).

once is the default record mode, used when you do not set one.

none

The none record mode will:

• Replay previously recorded interactions.
• Cause an error to be raised for any new requests.

This is useful when your code makes potentially dangerous HTTP requests. The none record mode guarantees that no new HTTP requests will be made.

new_episodes

The new_episodes record mode will:

• Record new interactions.
• Replay previously recorded interactions.

It is similar to the once record mode, but will always record new interactions, even if you have an existing recorded one that is similar (but not identical, based on the match_request_on option).

all

The all record mode will:

• Record new interactions.
• Never replay previously recorded interactions.

This can be temporarily used to force vcr to re-record a cassette (i.e. to ensure the responses are not out of date) or can be used when you simply want to log all HTTP requests.

More documentation

Check out the http testing book for a lot more documentation on vcr, webmockr, and crul