rails link_to_function file download

In a rails 2.3.11 app I'm trying to register file downloads that are availabl开发者_运维知识库e only to logged on users. When they click on the link to download the file (that is a direct link to a file in the public directory) I want the rails app to call a method.

I guess I should use link_to_function, I'm ok with writing the javascript/method in rails to record the download.

I don't know how I have to let the file download continue after the method has been called. After the method call (that is in the background), the file download should start.

Any ideas?

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You're probably over-thinking this, there's no need for Javascript. What you want is a link to a download action, which in turn registers the download and then streams the file back. This should work fine unless you have a really large file that you don't want Rails to have to process.

An example of sending a binary file back from the controller:

send_data(binary_data, :type => 'application/pdf', :filename => 'myfile.pdf', :disposition => 'inline' )

or even better:

render :content_type => 'application/octet-stream', :text => Proc.new { |response, output|
    # do something that reads data and writes it to output
}

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The answer from Abdullah Jibaly works perfect is has the advantage of not needing Javascript.

I ended up implementing a jQuery javascript solution that leaves the file download as before.

The link in my view, adding the download class is important for the js to work:

<%= link_to document.type.value, document.scan.url, :popup => true, :class => "download" %>

The added javascript, I add a property_id as data to post, because I need that value in my controller:

  <script type="text/javascript">
    $(document).ready(function() {
      $(".download").click(function(event){
        $.post("/ajax/property_interested_user", { property_id: $("#property_id").html() });
      });
    });
  </script>