vcr configuration

vcr configuration


Get configuration

Use vcr_configuration() to get the current configuration.


You can also get the default configuration variables via vcr_config_defaults()


These defaults are set when you load vcr - you can override any of them as described below.

Set configuration variables

Use vcr_configure() to set configuration variables.

For example, set a single variable:

  dir = "foobar/vcr_cassettes"

Or many at once:

  dir = "foobar/vcr_cassettes",
  record = "all"

Re-set to defaults


Details on some of the config options


Directory where cassettes are stored

vcr_configure(dir = "new/path")


The record mode

One of: ‘all’, ‘none’, ‘new_episodes’, ‘once’. See ?recording for info on the options

vcr_configure(record = "new_episodes")


Customize how vcr matches requests

vcr_configure(match_requests_on = c('query', 'headers'))


Allow HTTP connections when no cassette

Default is TRUE, and thus does not error when http interactions are unused. You can set to FALSE in which case vcr errors when a cassette is ejected and not all http interactions have been used.

vcr_configure(allow_unused_http_interactions = FALSE)


Which serializer to use. Right now only option is “yaml”

vcr_configure(serialize_with = "yaml")


Which persister to use. Right now only option is “FileSystem”

vcr_configure(persist_with = "FileSystem")

ignoring some requests


Specify particular hosts to ignore. By ignore, we mean that real HTTP requests to the ignored host will be allowed to occur, while all others will not.

vcr_configure(ignore_hosts = "")


Ignore all localhost requests

vcr_configure(ignore_localhost = TRUE)



How to ignore requests

For ignoring requests, you can for example, have real http requests go through (ignored by vcr) while other requests are handled by vcr. For example, let’s say you want requests to to be ignored:

vcr_configure(ignore_hosts = "")
use_cassette("foo_bar", {

The request to will be handled by vcr, a cassette created for the request/response to that url, while the request will be ignored and not cached at all.

Note: ignoring requests only works for the crul package for now; it should work for httr in a later vcr version.


Which uri parser to use

By default we use crul::url_parse, but you can use a different one. Remember to pass in the function quoted, and namespaced.

vcr_configure(uri_parser = "urltools::url_parse")


Some HTTP servers are not well-behaved and respond with invalid data. Set preserve_exact_body_bytes to TRUE to base64 encode the result body in order to preserve the bytes exactly as-is. vcr does not do this by default, since base64-encoding the string removes the human readability of the cassette.

vcr_configure(preserve_exact_body_bytes = TRUE)


A named list of values to replace. Sometimes your package or script is working with sensitive tokens/keys, which you do not want to accidentally share with the world.

Before recording (writing to a cassette) we do the replacement and then when reading from the cassette we do the reverse replacement to get back to the real data.

  filter_sensitive_data = list("<some_api_key>" = Sys.getenv('MY_API_KEY'))

Before recording to disk, the env var MY_API_KEY is retrieved from your machine, and we find instances of it, and replace with <some_api_key>. When replaying to create the HTTP response object we put the real value of the env var back in place.

More documentation

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