In order to improve performance for HTTP API clients, httpcache provides simple tools for
caching and invalidating cache. It includes the HTTP verb functions GET, PUT,
PATCH, POST, and DELETE, which are drop-in replacements for those in
the httr package. These functions are cache-aware
and provide default settings for cache invalidation suitable for RESTful APIs; the package also enables custom
cache-management strategies. Finally, httpcache includes a basic logging framework to facilitate
the measurement of HTTP request time and cache performance.
Installing
httpcache can be installed from CRAN with
install.packages("httpcache")The pre-release version of the package can be pulled from GitHub using the remotes package:
# install.packages("remotes")
remotes::install_github("nealrichardson/httpcache")Getting started
Working with httpcache is as simple as loading the package in your interactive session or script
instead of httr, or, in package development, importing the HTTP verb functions from
httpcache. GET() responses are added to the
local query cache; PUT(),
PATCH(),
POST(), and
DELETE() requests trigger cache invalidation on the
associated resources. You can override that default cache invalidation, and you can command the invalidation
explicitly, with the invalidation functions dropCache(),
dropPattern(), and
dropOnly().
clearCache() wipes the cache completely.
See vignette("httpcache") for examples of the HTTP cache in
practice.
For developers
The repository includes a Makefile to facilitate some common tasks.
Running tests
$ make test. Requires the httptest
package. You can also specify a specific test file or files to run by adding a “file=” argument, like
$ make test file=logging. test_package will do a regular-expression pattern match within
the file names. See its documentation in the testthat
package.
Updating documentation
$ make doc. Requires the roxygen2 package.