Question

I currently have a form (using form_tag). One of the fields is a dropdown list of options. Each option value matches the name of a method in my controller. What I want to do is when the form submit button is clicked, it runs the controller method corresponding directly to the value selected in the dropdown field.

I’ve built a work-around right now, but it feels too verbose:

def run_reports
  case params[:report_name]
    when 'method_1' then method_1
    when 'method_2' then method_2
    when 'method_3' then method_3
    when 'method_4' then method_4
    else method_1
end
# each method matches a method already defined in the controller 
# (i.e. method_1  is an existing method)

I had thought that it may work to use the dropdown option value to run the corresponding method in my controller through the form_tag action (i.e. :action => params[:report_name]), but this doesn’t work because the action in the form needs to be set before the params value is set. I don’t want to use javascript for this functionality.

Here is my form:

<%= form_tag("../reports/run_reports", :method => "get") do %>
  <%= select_tag :report_name, options_for_select([['--  Please Select  --',nil],['Option 1','method_1'], ['Option 2','method_2'], ['Option 3','method_3'], ['Option 4','method_4']]) %>
  <%= submit_tag "Run Report" %>
<% end %>

Any suggestions?

Can I change my controller method to look something like this – but to actually call the controller method to run? I’m guessing this won’t run because the params value is returned as a string…

def run_reports
  params[:report_name]
end

Answer 1

WARNING: this is a terrible idea

You could call the method via a snippet of code like this in the controller:

send(params[:report_name].to_sym)

The reason this is a terrible idea is that anyone accessing the page could manually construct a request to call any method at all by injecting a request to call something hazardous. You really, really do not want to do this. You’re better off setting up something to dynamically call known, trusted methods in your form.