Sometimes you may need to turn off vcr
, either for individual
function calls, individual test blocks, whole test files, or
for the entire package. The following attempts to break down
all the options.
vcr
has the following four exported functions:
turned_off()
- Turns vcr off for the duration of a code blockturn_off()
- Turns vcr off completely, so that it no longer handles every
HTTP requestturn_on()
- turns vcr on; the opposite of turn_off()
turned_on()
- Asks if vcr is turned on, returns a booleanInstead of using the above four functions, you could use environment
variables to achieve the same thing. This way you could enable/disable
vcr
in non-interactive environments such as continuous integration,
Docker containers, or running R non-interactively from the command line.
The full set of environment variables vcr
uses, all of which accept
only TRUE
or FALSE
:
VCR_TURN_OFF
: turn off vcr altogether; set to TRUE
to skip any vcr
usage; default: FALSE
VCR_TURNED_OFF
: set the turned_off
internal package setting; this
does not turn off vcr completely as does VCR_TURN_OFF
does, but rather
is looked at together with VCR_IGNORE_CASSETTES
VCR_IGNORE_CASSETTES
: set the ignore_cassettes
internal package
setting; this is looked at together with VCR_TURNED_OFF
turned_off()
lets you temporarily make a real HTTP request without completely turning
vcr
off, unloading it, etc.
What happens internally is we turn off vcr
, run your code block, then on exit
turn vcr
back on - such that vcr
is only turned off for the duration of your
code block. Even if your code block errors, vcr
will be turned back on
due to use of on.exit(turn_on())
library(vcr) library(crul) turned_off({ con <- HttpClient$new(url = "https://httpbin.org/get") con$get() })
#> <crul response> #> url: https://httpbin.org/get #> request_headers: #> User-Agent: libcurl/7.54.0 r-curl/4.3 crul/0.9.0 #> Accept-Encoding: gzip, deflate #> Accept: application/json, text/xml, application/xml, */* #> response_headers: #> status: HTTP/1.1 200 OK #> date: Fri, 14 Feb 2020 19:44:46 GMT #> content-type: application/json #> content-length: 365 #> connection: keep-alive #> server: gunicorn/19.9.0 #> access-control-allow-origin: * #> access-control-allow-credentials: true #> status: 200
turn_off()
is different from turned_off()
in that turn_off()
is not aimed
at a single call block, but rather it turns vcr
off for the entire package.
turn_off()
does check first before turning vcr
off that there is not currently
a cassette in use. turn_off()
is meant to make R ignore vcr::insert_cassette()
and vcr::use_cassette()
blocks in your test suite - letting the code in the block
run as if they were not wrapped in vcr
code - so that all you have to do to run
your tests with cached requests/responses AND with real HTTP requests is toggle
a single R function or environment variable.
library(vcr) vcr_configure(dir = tempdir()) # real HTTP request works - vcr is not engaged here crul::HttpClient$new(url = "https://eu.httpbin.org/get")$get() # wrap HTTP request in use_cassette() - vcr is engaged here use_cassette("foo_bar", { crul::HttpClient$new(url = "https://eu.httpbin.org/get")$get() }) # turn off & ignore cassettes - use_cassette is ignored, real HTTP request made turn_off(ignore_cassettes = TRUE) use_cassette("foo_bar", { crul::HttpClient$new(url = "https://eu.httpbin.org/get")$get() }) # if you turn off and don't ignore cassettes, error thrown turn_off(ignore_cassettes = FALSE) use_cassette("foo_bar", { res2=crul::HttpClient$new(url = "https://eu.httpbin.org/get")$get() }) # vcr back on - now use_cassette behaves as before turn_on() use_cassette("foo_bar3", { res2=crul::HttpClient$new(url = "https://eu.httpbin.org/get")$get() })
turned_on()
does what it says on the tin - it tells you if vcr
is turned on
or not.
library(vcr) turn_on() turned_on() turn_off() turned_on()
The VCR_TURN_OFF
environment variable can be used within R or on the command line
to turn off vcr
. For example, you can run tests for a package that uses vcr
, but
ignore any use_cassette
/insert_cassette
usage, by running this on the command
line in the root of your package:
VCR_TURN_OFF=true Rscript -e "devtools::test()"
Or, similarly within R:
Sys.setenv(VCR_TURN_OFF = TRUE) devtools::test()
The VCR_TURNED_OFF
and VCR_IGNORE_CASSETTES
environment variables can be used
in combination to achieve the same thing as VCR_TURN_OFF
:
VCR_TURNED_OFF=true VCR_IGNORE_CASSETTES=true Rscript -e "devtools::test()"
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