Parse a string as if it were a querystring in Ruby on Rails

Question

The answer depends on the version of Rails that you are using. If you are using 2.3 or later, use Rack's builtin parser for params

 Rack::Utils.parse_nested_query("a=2") #=> {"a" => "2"}

If you are on older Rails, you can indeed use CGI::parse. Note that handling of hashes and arrays differs in subtle ways between modules so you need to verify whether the data you are getting is correct for the method you choose.

You can also include Rack::Utils into your class for shorthand access.

The

CGI::parse("foo=bar&bar=foo&hello=hi")

Gives you

{"foo"=>["bar"], "hello"=>["hi"], "bar"=>["foo"]}

Edit: As specified by Ryan Long this version accounts for multiple values of the same key, which is useful if you want to parse arrays too.

Edit : as said in the comments, symolizing keys can bring your server down if someone want to hurt you. I still do it a lot when I work on low profile apps because it makes things easier to work with but I wouldn't do it anymore for high stake apps

Do not forget to symbolize the keys for obtaining the result you want

Rack::Utils.parse_nested_query("a=2&b=tralalala").deep_symbolize_keys

this operation is destructive for duplicates.

If you talking about the Urls that is being used to get data about the parameters them

> request.url
=> "http://localhost:3000/restaurants/lokesh-dhaba?data=some&more=thisIsMore"

Then to get the query parameters. use

> request.query_parameters
=> {"data"=>"some", "more"=>"thisIsMore"}

If you want a hash you can use

Hash[CGI::parse(x).map{|k,v| [k, v.first]}]