render :update to |page| 2

Posted by Daniel Wanja Tue, 18 Apr 2006 11:54:00 GMT

In the following test I was checkeing out of the javascript that is generated using the render :update call. Note that using a functional test is also a nice way to explore some of the prototype_helper functionality.

page.call 'mycall', 'a', 2, 3      # -->  mycall("a", 2, 3);'
page.my_class.my_method 'a', 12    # -->  MyClass.myMethod("a", 12);
Now one issue I had was figuring out how to pass a javascript variable to a javascript call. I.e. mycall(p1, p2). The only way I found it so to use the page << method. After a little hacking I managed to pass javascript variables to a method using the page.call. See the use of the JsArugmentList class here after. Note it does get’s a little cluttered and the page << remains easier to read. Please let me know if you find a more elegant way to achieve this.
rjs_test.rb
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require File.dirname(__FILE__) + '/../test_helper'

# Little hack to allow passing javascript variables as argument to page.call
class JsArgumentList
  def initialize(*arguments)
    @arguments = arguments
  end
  def to_json
    @arguments.join ', '
  end
end

class RjsController < ActionController::Base
  def rescue_action(e) raise e end;
  # See prototype_helper.rb for implementation of the 'page' methods.
  def page_call
    render :update do |page|
      page.call 'mycall', 'a', 2, 3
      page.assign 'p1', 'str1'
      page << 'mycall(p1, p2);' 
      page.call 'mycall', JsArgumentList.new(:p1,:p2)  #equivalent to previous line
      page.my_class.my_method 'a', 12 
    end
  end
end

class RjsControllerTest < Test::Unit::TestCase
  def setup
    @controller = RjsController.new
    @request    = ActionController::TestRequest.new
    @response   = ActionController::TestResponse.new
  end
  def test_page_call
    get :page_call
    javascript = @response.body.split("\n")
    assert_equal 'mycall("a", 2, 3);',          javascript[0]
    assert_equal 'p1 = "str1";',                javascript[1]
    assert_equal 'mycall(p1, p2);',            javascript[2]
    assert_equal 'mycall(p1, p2);',            javascript[3]
    assert_equal 'MyClass.myMethod("a", 12);',  javascript[4]
  end
end
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  1. sayoyo Wed, 17 Jan 2007 20:31:47 GMT

    Question, what is |page| exactly? a ruby-rails obj? a js obj? or a user defined obj? why it can receive ”.call”, ”.assign” or ”<<” ????

  2. Lee Wed, 17 Jan 2007 20:59:19 GMT

    page is a JavaScriptGenerator object which is part of Rails It basically takes Ruby code and turns it into JavaScript.

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