The class Iri helps you build a URI and then modify its parts via a simple fluent interface:

require 'iri'
url = Iri.new('http://google.com/')
  .append('find').append('me') # -> http://google.com/find/me
  .add(q: 'books about OOP', limit: 50) # -> ?q=books+about+OOP&limit=50
  .del(:q) # remove this query parameter
  .del('limit', 'speed') # also remove these two
  .over(q: 'books about tennis', limit: 10) # replace these params
  .scheme('https') # replace 'http' with 'https'
  .host('localhost') # replace the host name
  .port('443') # replace the port
  .fragment('page-4') # replaces the fragment part of the URI, after the '#'
  .query('a=1&b=2') # replaces the entire query part of the URI
  .path('/new/path') # replace the path of the URI, leaving the query untouched
  .cut('/q') # replace everything after the host and port
  .to_s # convert it to a string

The full list of methods is here.

Install it:

$ gem install iri

Or add this to your Gemfile:

gem 'iri'

Pay attention, it is not a parser. The only functionality this gem provides is building URIs.

It is very convenient to use inside HAML, for example:

- iri = Iri.new(request.url)
%a{href: iri.over(offset: offset + 10)} Next Page
%a{href: iri.over(offset: offset - 10)} Previous Page

Of course, it's better to create the iri object only once per request and re-use it where you need. It's immutable, so you won't have any side-effects.

PS. See how I use it in this Sinatra web app: yegor256/0rsk.

How to contribute

Read these guidelines. Make sure you build is green before you contribute your pull request. You will need to have Ruby 2.3+ and Bundler installed. Then:

$ bundle update
$ bundle exec rake

If it's clean and you don't see any error messages, submit your pull request.