How can i add parameter to the given url which is dynamic in rails

Question

I have page having url

http://localhost:3000/athletes/list

When user search on this page it changes to something like

http://localhost:3000/athletes/list?first_name=sachin&last_name=tendulkar

Where first_name and last_name are the search parameters when user search.

I want a link which add the parameter view_type=something in url for ex. For 1st URL

http://localhost:3000/athletes/list?view_type=something

For 2nd URL

http://localhost:3000/athletes/list?first_name=sachin&last_name=tendulkar&view_type=something

I have tried following

<%= link_to "Something ", :view_type => 'something' %>

But for both url it gives following url

http://localhost:3000/athletes/list?view_type=something

Answer 1

<%= link_to "Something ", params.merge(:view_type => 'something')  %>

Though above code works in most of the cases for some reason it is giving error for some url may be because i am using friendly_url for ex.

for url

http://localhost:3000/athlete/sachin_ramesh_tendulkar_1

giving me following wrong url

http://localhost:3000/athlete/1?view_type=something

To fixed this i am using javascript method as follows

function something(){
    var par =""
    var link =window.location.href
    if (link.indexOf('view_type=something') == -1)
        par = link.indexOf('?') != -1 ? "&view_type=something" : "?view_type=something"
    window.location.href = link+par
}

and rails code

<%= link_to "Something ", "javascript:void(0)", :onclick => "something();"  %>

Answer 2

this might be useful as well (from the API)

http://apidock.com/rails/ActionView/Helpers/UrlHelper/link_to#343-link-to-some-url-with-current-params