setup_knitr: Use vcr in vignettes

In vcr: Record 'HTTP' Calls to Disk

Use vcr in vignettes

Description

setup_knitr() registers a knitr hook to make it easy to use vcr inside a vignette. First call setup_knitr() in your setup chunk (or other chunk early in the document):

```{r setup}
#| include: false
vcr::setup_knitr()
```

Then, in a chunk where you want to use a cassette, set the cassette chunk option to the name of the cassette:

```{r}
#| cassette: name
req <- httr2::request("http://r-project.org")
resp <- httr2::req_perform(req)
```

Or if you have labelled the chunk, you can use cassette: true to use the chunk label as the cassette name:

```{r}
#| label: cassette-name
#| cassette: true
req <- httr2::request("http://r-project.org")
resp <- httr2::req_perform(req)
```

You can build your vignettes however you usually do (from the command line, with pkgdown, with RStudio/Positron, etc).

Usage

setup_knitr(prefix = NULL, dir = "_vcr", ...)

Arguments

prefix	An prefix for the cassette name to make cassettes unique across vignettes. Defaults to the file name (without extension) of the currently executing vignette.
dir	Directory where to create the cassette file. Default: '"_vcr"“.
...	Other arguments passed on to insert_cassette().

vcr documentation built on Aug. 8, 2025, 6:45 p.m.