holy sweet victory

Just figured out something that's been bugging me nonstop for weeks, which has no documentation online: the jquery plugin fancybox doesn't like to have its stuff overwritten, which is to say, you shouldn't define something like this:

var fancy_box_options = fancy_box_defaults;
fancy_box_options.type = 'iframe';
fancy_box_options.width = 696;
fancy_box_options.height = 499;
fancy_box_options.scrolling = 'no';
fancy_box_options["onStart"] = function(link){
var new_link = $.param.querystring($(link).attr("href"), "gmail=" + $("#gmail").val());
$(link).attr("href", new_link);
};

$("a.iframe").fancybox(fancy_box_options);
$("a.iframe_defaults").fancybox();

In one function, and then soon after define:

<% if current_user && @popup_help %>
var fancy_box_options = fancy_box_defaults;
fancy_box_options.type = 'iframe';
fancy_box_options.width = 696;
fancy_box_options.height = 499;
fancy_box_options.scrolling = 'no';

fancy_box_options.href = '<%= popup_help_path(:gmail => current_user.email) %>';
$.fancybox(fancy_box_options);

in another. You'll get a wholly unhelpful error about href being undefined.

All better now -
#facepalms only 4, because I already had a lot of trouble with this previously, I'm over it now, and the sweet release of figuring it out is worth so, so much.

rails fields_for, object sorting

So what I needed to do was select a subset of one model which happened to have a key into another, sort it by an attribute of the other model, and display a list of the results in a form.
here's the query to find, filter, join, and order:

@user_categories = Category.joins(:user_categories).where('user_categories.user_id' => current_user.id).order("name asc")

and here's the bit of the form:

<%= f.fields_for :user_categories, @user_categories do |user_category| %>

and then to access the objects:

<%= user_category.label :name, user_category.object.name %>

Things to notice:
the fields_for uses a parameter :user_categories which references the name of the model, followed by the object which is actually a list of objects of type Category, so I'm assuming this is to let rails know how to treat it. Also, note that to reference the actual objects, you have to use model_class.object.method. the model_class is actually some sort of form builder helper before the call to .object.

This only took an hour to figure out - #facepalms = 3.

Rails 3 Unobtrusive Javascript is Unintuitve

So what I wanted to do was link from a partial view to a controller method through a route which took a title parameter and from the controller method run a javascript file in order to append content to a div with a unique name defined by the title param.

In django it's pretty straightforward, but ruby on rails 3 had me scratching my head for a good long while.

Here's the solution, or at least the parts that were difficult:

the link:

<%= link_to "Comments", show_comments_path( :format => 'js', :comment_id=> session[:id] ), :remote => true %>

This whole :remote => true business tells rails 3 that this is an ajax call. The :format param does NOT get passed into the url, but DOES render the response as html, most of the time. Which is to say, rails will run the .js.erb file with the name matching your route.

Here's the route:

match 'show_comments/:comment_id', :to => 'deals#show_comments', :as => :show_comments

So first rails runs the show_comments method from the appropriate controller, which you can use to set state variables for the javascript. Then, whatever is in show_comments.js.erb will be run, and the current page will NOT be reloaded or redirected. No partial needed. No view needed. The controlling method will do all of this as the default return, so no return or render needed either, only the .js.erb file which has your prototype or jquery calls, or whathaveyou.

facepalms: 4 (steady, slow, only slightly infuriating progress)