With URITemplate you can generate URIs based on simple templates and extract variables from URIs using the same templates. There are currently two syntaxes defined. Namely the one defined in RFC 6570 and a colon based syntax, similiar to the one used by sinatra.

From version 0.2.0, it will use escape_utils if available. This will significantly boost uri-escape/unescape performance if more characters need to be escaped ( may be slightly slower in trivial cases. working on that ... ), but does not run everywhere. To enable this, do the following:

# escape_utils has to be loaded when uri_templates is loaded
gem 'escape_utils'
require 'escape_utils'

gem 'uri_template'
require 'uri_template'

UriTemplate::Utils.using_escape_utils? #=> true

require 'uri_template'

tpl = URITemplate.new('http://{host}{/segments*}/{file}{.extensions*}')

# This will give: http://www.host.com/path/to/a/file.x.y
tpl.expand('host'=>'www.host.com','segments'=>['path','to','a'],'file'=>'file','extensions'=>['x','y'])

# This will give: { 'host'=>'www.host.com','segments'=>['path','to','a'],'file'=>'file','extensions'=>['x','y']}
tpl.extract('http://www.host.com/path/to/a/file.x.y')

# If you like colon templates more:
tpl2 = URITemplate.new(:colon, '/:x/y')

# This will give: {'x' => 'z'}
tpl2.extract('/z/y')

The syntax defined by RFC 6570 is pretty straight forward. Basically anything surrounded by curly brackets is interpreted as variable.

URITemplate.new('{variable}').expand('variable' => 'value') #=> "value"

The way variables are inserted can be modified using operators. The operator is the first character between the curly brackets. There are seven operators defined #, +, ;, ?, &, / and .. So if you want to create a form-style query do this:

URITemplate.new('{?variable}').expand('variable' => 'value') #=> "?variable=value"

I have assembled one benchmark based on the uritemplate-test examples. You can find them in the "benchmarks" folder. The short result: uri_template is 2-10x faster than addressable on ruby 1.9.3.