can rails send data to browser chunk by chunk?

Question

Hello all,

I have a very large dataset (100,000) to be display, but any browser I tried that on including chrome 5 dev, it make them choke for dozens of seconds (win7 64bit, 4gb, 256gb ssd, c2duo 2.4ghertz). I did a little experiment by

some_controller.rb

def show @data = (1..100000).to_a end

show.html.erb

<% @data.each do |d| %> <%= d.to_s %> <% end%>

as simple as that it chokes the browsers. I know browsers were never built for this, so I thought to let the data come in chunk by chunk, I guess 2000 per chunk is reasonable, but I wouldn't want to make 50 requests each time this view is called, any ideas? It doesn't have to be chunk by chunk if it can be sent all at once.

Best,

Answer 1

One way to accomplish this would be to use render, passing it a proc. The snippet of code below is from the Rails documentation.

# Streams about 180 MB of generated data to the browser.
render :text => proc { |response, output|
  10_000_000.times do |i|
    output.write("This is line #{i}\n")
    output.flush
  end
}

http://api.rubyonrails.org/classes/ActionController/Base.html#M000658

Answer 2

I did see a plugin that allowed this sort of thing, but I can't remember what it was called .... will keep trawling my notes.

In the meantime, this is what pagination is for :p

If you use-case doesn't support that, perhaps using AJAX would streamline things ... can use AJAX to load out the data incrementally, either as the user scrolls or automatically.

UPDATE: found the template streaming plugin: http://github.com/oggy/template_streaming