pater

The goal of pater is to decompose a given pathname into meaningful tokens that will be later used to construct a regular expression useful when matching an HTTP request to a route handler.

Core to this are path parameters which are pieces of text you define in your route definitions and that will be filled when a new request comes in, they are useful because they act as identifiers for a given concept you care about.

Path parameters can appear anywhere you want inside a given path, they may share the same path segment or be next to plain text, given this the following are valid positions for path parameters:

• /text/:parameter
• /text/:parameter1-:parameter2
• /text1/:parameter1/text2{.:parameter2}
• /text1/*parameter

pater borrows its syntax from the original path-to-regexp implementation that you can read, understand and experiment with pater in R as the R implementation tries to be as close as possible to the original.

Installation

You can install the stable version of pater from CRAN with:

install.packages("pater")

You can install the development version of pater like so:

# install.packages("pak")
# pak::pak("JulioCollazos64/pater")
install.packages("pater", repos = c('https://juliocollazos64.r-universe.dev', 'https://cloud.r-project.org'))

Common patterns

• Parameters

library(pater)
#> 
#> Attaching package: 'pater'
#> The following objects are masked from 'package:base':
#> 
#>     match, parse
fn <- match("/path/:foo")
fn("/path/bar")
#> $path
#> [1] "/path/bar"
#> 
#> $params
#> $params$foo
#> [1] "bar"

fn <- match("/path/:foo-:bar")
fn("/path/foo-bar")
#> $path
#> [1] "/path/foo-bar"
#> 
#> $params
#> $params$foo
#> [1] "foo"
#> 
#> $params$bar
#> [1] "bar"

• Optional parameters

library(pater)
fn <- match("/foo{/:bar}")
fn("/foo")
#> $path
#> [1] "/foo"
#> 
#> $params
#> list()
fn("/foo/bar")
#> $path
#> [1] "/foo/bar"
#> 
#> $params
#> $params$bar
#> [1] "bar"

• Wildcard

library(pater)
fn <- match("/*foo")
fn("/foo/bar")
#> $path
#> [1] "/foo/bar"
#> 
#> $params
#> $params$foo
#> [1] "foo" "bar"