How to get a query string from a URL in Rails

ruby, ruby-on-rails, ruby-on-rails-3

Solution

If you have a URL in a string then use URI and CGI to pull it apart:

require 'cgi'

url    = 'http://www.example.com?id=4&empid=6'
uri    = URI.parse(url)
params = CGI.parse(uri.query)
# params is now {"id"=>["4"], "empid"=>["6"]}

id     = params['id'].first
# id is now "4"

Please use the standard libraries for this stuff, don't try and do it yourself with regular expressions.

Also see Quv's comment about `Rack::Utils.parse_query` below.

References:

- `CGI.parse`

- `URI.parse`

Update: These days I'd probably be using `Addressable::Uri` instead of `URI` from the standard library:

require "addressable/uri"

url = Addressable::URI.parse('http://www.example.com?id=4&empid=6')
url.query_values                  # {"id"=>"4", "empid"=>"6"}
id    = url.query_values['id']    # "4"
empid = url.query_values['empid'] # "6"

Problem

Is there is a way to get the query string in a passed URL string in Rails? I want to pass a URL string: ``` http://www.foo.com?id=4&empid=6 ``` How can I get `id` and `empid`?

Original source

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