Parse a string as if it were a querystring in Ruby on Rails
Ruby on-RailsParsingQuery StringRuby on-Rails Problem Overview
I have a string like this:
"foo=bar&bar=foo&hello=hi"
Does Ruby on Rails provide methods to parse this as if it is a querystring, so I get a hash like this:
{
:foo => "bar",
:bar => "foo",
:hello => "hi"
}
Or must I write it myself?
EDIT
Please note that the string above is not a real querystring from a URL, but rather a string stored in a cookie from Facebook Connect.
Ruby on-Rails Solutions
Solution 1 - Ruby on-Rails
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.
Solution 2 - Ruby on-Rails
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 2:
As Ben points out, this may not handle arrays well when they are formatted with ruby on rails style array notation.
The rails style array notation is: foo[]=bar&foo[]=nop
. That style is indeed handled correctly with Julik's response.
This version will only parse arrays correctly, if you have the params like foo=bar&foo=nop
.
Solution 3 - Ruby on-Rails
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.
Solution 4 - Ruby on-Rails
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"}
Solution 5 - Ruby on-Rails
If you want a hash you can use
Hash[CGI::parse(x).map{|k,v| [k, v.first]}]