Using Javascript's prompt() and render_component to make one

Rails
1

Hi,
I’m trying to use a combination of render_component and Javascript’s
prompt() to make one Rails action interactive. This means I could ask
for input via Javascript and then pass the Javascript answer to some
Ruby code. Is this possible?
For example:

======
class FilesController < ApplicationController
def js_save
$answer = params[:answer]
render :nothing=>true
end

def js_ask
render :inline=>%[
<%= javascript_include_tag :defaults %>

]
end

def some_action
a = “default value”
render :inline=>%[
<%= render_component :action=>‘js_ask’, :params=>{
:prompt=>‘1st value of a?’} %>

  <%# set a to the new answer, $answer %>
  <%# a = $answer %>
  <%# render_component :action=>'js_ask', :params=>{
    :prompt=>'2nd value of a?'} %>
], :layout=>true

end
end

======
Note: Try the above with /files/some_action

My main problem is that I can’t get back the JS variable answer while
I’m still in some_action(). Possible ways I thought of returning
answer:

  • an Ajax request (commented out), passing answer as a parameter:
    This doesn’t work since the request is executed
    after some_action().
  • a JS redirect (window.location.href = ‘’, passing answer as a
    parameter: Same as above.
  • writing to a file/database or using a
    system call and have Ruby read from wherever JS wrote: I’ve read
    that JS file manipulation and system calls aren’t possible for
    security reasons. Even if I could this, seems like a convoluted way
    of passing a value.

Given my limited knowledge of JS, is there some obvious way I’m
missing to return a JS value to Ruby within a Rails action?

If you’re wondering why I have the one Rails action constraint, it’s
due to using callcc() (not shown above) which only works within one web
request/action.
Otherwise, I get threading errors.

Thanks,
Gabriel