Ruby / Roda - Web Framework / Plugins / :symbol_matchers

Introduction

The :symbol_matchers plugin allows you do define custom regexps to use for specific symbols.

For example, if you have a route such as:

r.on :username do
    # ...
  end

By default this will match all nonempty segments. However, if your usernames must be 6-20 characters, and can only contain a-z and 0-9, you can do:

plugin :symbol_matchers
  symbol_matcher :username, /([a-z0-9]{6,20})/

Then the route will only if the path is /foobar123, but not if it is /foo, /FooBar123, or /foobar_123.

Note that this feature does not apply to just symbols, but also to embedded colons in strings, so the following:

r.on "users/:username" do
    # ...
  end

Would match /users/foobar123, but not /users/foo, /users/FooBar123, or /users/foobar_123.

By default, this plugin sets up the following symbol matchers:

Matchers: RegExp: Description:
:d /(\d+)/ a decimal segment
:format /(?:\.(\w+))?/ an optional format/extension
:opt /(?:\/([^\/]+))? an optional segment
:optd /(?:\/(\d+))? an optional decimal segment
:rest /(.*)/ all remaining characters, if any
:w /(\w+)/ a alphanumeric segment

Note! Because of how segment matching works, :format, :opt, and :optd are only going to work inside of a string, like this:

r.is "album:opt" do |id| end
  # matches /album (yielding nil) and /album/foo (yielding "foo")
  # does not match /album/ or /album/foo/bar

ClassMethods

#.symbol_matcher(s, re)

Set the regexp to use for the given symbol, instead of the default.