04 June 2008

Rails, jQuery, auto-complete, and a New Plugin

Update: I've switched which jQuery autocomplete plugin I use for this, see my newer blog entry.

The other day, I made a whole switch from Prototype & Scriptaculous to jQuery. I've had the bug to do this for a while, and this is a new project, so I went for it. I don't have anything against Prototype, so my main impetus for this was a move towards Unobtrusive JavaScript, and also the speed aspect (the site I'm currently working on, if things go accordingly to plan, will do some pretty serious traffic). But, the unobtrusive JavaScript was the key, and really, my switch is more of a philosophy of approach rather than say a dislike for Prototype, etc. And, of course, it's something new to play with :)

Before I go any further, I'll state right now, I am not a JavaScript expert, and I've been using jQuery now for all of a couple hours.

One of the results of my switch however, was that I hacked DHH's auto_complete Rails plugin, to work for jQuery. Simple change. I tweaked the controller macro, and then gutted the JS helpers, as you just don't need those when using jQuery in this way. It does require the jquery-autocomplete plugin for jQuery. I've published my Rails plugin for this on GitHub as auto_complete_jquery.

Circling back around, here's what I did to get all this going. I did run into one issue (see step 10 below) that I'm still tracking down (easy solution in the interim, but I'd like to understand what's happening, so if you have comments, please let me know):

  1. Removed the Prototype and Scriptaculous JS files from the public/javascripts dir of my Rails app. You don't have to do this, but I am no longer using them, so saw no need to keep them there, and it helps ensure I don't mistakenly use something from them or include them in the view. This includes: prototype.js, controls.js, dragdrop.js, and effects.js.

  2. Removed the prototype-based Rails auto_complete plugin from vendor/plugins.

  3. Installed the latest minified jQuery file in public/javascripts/jquery.

  4. Installed the JS files for the jquery-autocomplete plugin, and its dependencies: jquery.templating.js, and jquery.ui.autocomplete.js. (see the jquery-autocomplete plugin for these files).

  5. Added the jquery.ui.autocomplete.css file to public/stylesheets.

  6. Installed my auto_complete_jquery plugin.

  7. Put the proper includes for the CSS file and the JS files in my application layout file:

    <%= stylesheet_link_tag 'jquery.ui.autocomplete' %>
    <%= javascript_include_tag 'jquery/jquery.min', 'jquery/jquery.templating', 'jquery/jquery.ui.autocomplete.ext', 'jquery/jquery.ui.autocomplete', :cache => 'jquery' %>

    Note that I keep my jQuery JS files in a subdir for organizational purposes, but you can modify as needed.

  8. Changed my existing auto-complete text fields that used the Rails Prototype based auto_complete plugin's helpers to just be plain old text fields, such as:
    <%= coffee.text_field :drink, :autocomplete =>"off" %>
    This is doing an auto-complete for the "drink" attribute of the Coffee model.

  9. I can simply leave any auto_complete_for calls that existed in my controller, as that works the same. If you had custom versions that were based on the code from the Prototype-based Rails plugin, just go look at the code in my plugin to see the differences, it's a simple change.

  10. Add the JavaScript that sets up the auto-complete for the given text field. This will typically look like:

    $(document).ready(function() {
    $("input#coffee_drink").autocomplete({ ajax: "auto_complete_for_coffee_drink" })

    Where does this go? It depends. What I've been liking is using the JavaScript auto-include plugin, which creates a Rails-style convention for JavaScript files that pertain to individual actions, or are controller-wide. So in my case, this code would get placed in public/javascripts/views/coffees/new.js, or likely one directory up, as simply coffees.js (so that I can use it in any CoffeesController action that needs to auto-complete on coffee.drink. Without that plugin, you just put it in whatever JS file is appropriately included for the view you're using it in, etc. You can of course put it directly into the view in a script block, but then you aren't doing the whole Unobtrusive JavaScript thing as rigidly.
  11. Finally, what I found is that I had to add a route for this. This is the issue I mentioned above. It sort of makes sense, but what I'm unclear on is, why the prior standard/Prototype-based Rails auto_complete plugin didn't require a route. They both seem to use a GET, define the action the same way, and so on. I'm hoping I'm just missing something obvious. So, the route I added is:
    map.connect ':controller/auto_complete_for_coffee_drink', :action => 'auto_complete_for_coffee_drink', :format => 'json'

A bunch of steps, but pretty simple work. The app I'm doing this on is all of a few days old, so I hadn't gotten into use of much else in Prototype and so on, thus making the wholesale switch easy.

If you'd like to learn more about any of these things, and as a comprehensive set of links:


Update: I removed the jQuery Dimensions JS file and include for it in my layout, as this is now included in the latest jQuery JS file itself.

Update 2: I don't know how the standard auto_complete plugin manages to do without routes, but here is a generic route for all auto-complete actions across controllers:

map.auto_complete ':controller/:action',
:requirements => { :action => /auto_complete_for_\S+/ },
:conditions => { :method => :get }

I hesitate to put this into the plugin, as routes can be quite tricky in more complex apps, and I wouldn't want to auto-hose someone :)


JHill said...

Great idea... It doesn't look like all the files made it to github, though :)

Chris said...

jhill, Thanks! Not sure what happened there, but they're all there now, so try again.

JHill said...

Awesome, thanks!

Chris said...

I updated this entry to provide a single route definition that covers all auto_complete methods (see the end of the post).

dubbon said...

i have newbies question

i used latest jquery.js (1.2.6) i upload jquery.ui.autocomplete.js and others .
I put the files in http://sismit.securigo.com/
but i have problem with the auto-complete and how to install the RB files.
Thanks for the post

Chris said...

Dubbon, do you have a Ruby on Rails project? If so, you put all the JavaScripts into [your project dir]/public/javascript (or a subdirectory of that as I mentioned I do).

For my plugin, you can install it various ways. It's a regular Rails plugin, so you can git clone it into your plugins directory, or you can use a Git submodule if your own project is managed under Git. Finally, you can also just download it from GitHub, and extract it into your Rails app's plugins directory.

james said...

Have you had any issues like "this.match is not a function" when using this jQuery plugin?

Chris said...

James, I haven't seen that. I take it you are seeing it? Where is "this.match" being called?

CLR said...

On line 126 of jquery.ui.autocmplete.js, I had to change "opt.match.call( this, ...)" to "opt.match.call( this.text, ...)" to match the "text": structure of my JSON object being returned. This is in FF3 on Linux, version 1.0 of that file. I'm not sure why this evaluated correctly for you, but then I also had to modify the list builder because I was just getting li[object Object]/li until I also add ".text" to line 128.

Jay said...

I am also getting "this.match is not a function" on line 93 of jquery.ui.autocomplete.js. Using:

jQuery 1.2.6


Tim said...

I have this working in a rails project alongside jrails and for some reason I only get a single query out of it... after the first list is returned it does not do any more ajax calls.

Any ideas?

godfox said...

I am also getting "this.match is not a function" on line 108 of jquery.ui.autocomplete.js
=>"match: function(typed) { return this.match(new RegExp(typed)); }," and that js files downloaded from "http://github.com/ReinH/jquery-autocomplete/tree/master"

rails 2.1
firefox 3

Willys said...


Finance said...

You can remove the 'match' option and let the autocomplete plugin use the default.... then u wont get that error.

Thats what i did on here: Finance news

volvo auto parts said...

Hey guys!
i just started blogging not that long ago and running across this blog it seemed a bit too interesting to only read the first paragraph. I kinda got confused in the middle of it but the end just made it all go together like a puzzle. Please, who ever wrote this, keep me updated!

Anonymous said...

i was trying to follow this whith usuall scaffold coffee with atribute drink.
I wanted to display this autocomplete field in the view index, and i got erorr
undefined local variable or method `coffee'

thx for help

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