The dangers of using ExtJS on a big project with RoR?

Question

We are developing a considerably big application using Ruby on Rails framework (CRM system) and are considering to rewrite it to use ExtJS so that Rails would just do the data handling, while ExtJS would do all the browser heavylifting in a desktop-like manner.

Anyone has some experience and hints about what would be the best approach? Is ExtJS mature enough to be used in relatively big (and complex) applications? And what about the Rails part - what would be the best approach here?

EDIT:

Just to make it clear. I would prefer to do it in such a way that all the javascript client side application code is loaded at once (at the start up of the application, optimally as one compressed js file) and then just use ajax to send data to and from Rails app. Also, it would be nice to have ERB available for dynamic generation of the Ext apliccation elements.

Answer 1

Ext is definitely mature enough to handle this situation. I'm currently working on a Rails project with a lot of Ext, and the hardest part has definitely been working with Rails's to_json to render JSON that Ext can read (for arrays, hashes, models, which failed validation, etc.)

Check out the ext_scaffold plugin for Rails. I started with this and hacked away at its ActiveRecord/ActionView extensions until it did what I needed it to do.

Answer 2

I has some experience using ExtJS with Rails too. Using the framework is a great way to get some nice looking widgets for free. REST convention should sit well with the framework too if you use it to develop single page applications. Works well with RJS too.

Here are my gripes with using the framework

1. You can't really make use of flash[:notice] since reloading a single page application is silly. This makes passing validation notices and messages a chore since you have to use RJS/ javascript methods to show them.

2. You can't use erb much thus you have to encapsulate a lot of the logic into the json callbacks.

Answer 3

ExtJS is great on technical merits, but the fiasco with the licensing several months ago have led me to look at other frameworks - I don't trust the creators of ExtJS at all now. I don't like how they worded their license, and how they pretended to be open source advocates whilst obviously attempting to profit unfairly off those who believed them.

I'm only against using ExtJS on moral grounds.

Answer 4

I've successfully deployed a large RoR/ExtJS app of the kind you describe ("single-page" client-side AJAX driven). Ext_scaffold is pretty much a red-herring.

It's not too taxing to get RoR and ExtJS working smoothly together. The fundamental choice is whether to extend ExtJS to "speak Rails", patch RoR to "speak ExtJS", or meet in the middle. It's going to depend where your team's skills are.

I adopted the meet-in-the-middle strategy, which includes:

• Extend Ext.data.Store and Ext.data.Record to be aware of Rails routing conventions
• Hack Ext.grid.EditorPanel and Ext.form.BasicForm to play well with ActiveRecord associations
• Write some modules to extend ActiveRecord::Base and ApplicationController to simply commits from Ext.grid.EditorPanel and Ext.form.BasicForm

That's pretty much it.

Having said that, there are drawbacks to ExtJS.

• You're going to have to get your hands dirty in the internals. Don't be beguiled by the demos.
• The community documentation is poor and PHP-centric.
• Coming from the Github/Lighthouse-centred RoR world, using VBulletin is like waking up in 1998. I mean, there's no public bugtracker just a forum post that's updated (WTF?).
• The code is a bit over-engineered.
• The team have lost Open Source credibility so they've lost Open Source oxygen.
• The team appear to be focused integration with GWT (can anyone say "enterpri$ey"?).

Answer 5

While I have no experience of ExtJS (besides reading about in the "Practical Rails Projects" book) I used a jQuery Flexigrid with jrails to get more of a desktop feel.

That worked pretty well.

Answer 6

I've deployed ExtJS and Rails for a number of applications and they certainly can be made to talk to each other. We've put together a quick demo of an app we're currently developing in Rails + Ext at http://demo.domine.co.uk/admin. Ignore the front end for now as it's not complete - the admin section is essentially finished and you can log in to it with:

username: edward password: rarrar

As the demo's not completely finished yet I won't guarantee that it works correctly in anything other than Firefox at this stage. There's no reason for it not to work in other browsers, I just haven't spent any time testing them yet. The point is more about the integration with rails though.

Every application on the start menu is interacting with the Rails backend via JSON. I've written a basic Rails plugin to do most of the work for us there. I'll be releasing the code behind that shortly but for now hopefully that gives some idea of how well these two technologies can work together...

Answer 7

This belongs in answer to Milan's comment on my previous answer, but as a newcomer here I don't have enough reputation points to reply there:

There was a problem with the "sp is undefined", which was a result of Rails' caching of the JavaScript files into one large file (there would be several hundred files otherwise). The caching introduced some weird bugs with newlines which threw the whole thing off. This had me pulling my hair out for a while, but the solution was to update Ruby from 1.8.6 (patch level 72) to the latest 1.8.7. This fixed the problem so please check it again if you want to have a look (you'll need to do a full refresh to beat the asset caching).

I'm glad you've come across the Ext MVC stuff before. At present I can fully believe it must be quite difficult to understand, mainly due to a lack of examples, tutorials and demos. The code itself is reasonably well documented however (at least the newer code anyway, there is a lot which needs clearing out).

I am currently in the process of refactoring a few key classes before it is ready for a proper 'release'. When that's ready (I'm thinking a couple of weeks), I will generate the documentation and set up a quick site with some demos and example code. When I've done so I'll put up a post on my blog (http://edspencer.net).

My aim with this is to try to provide a framework which will make writing this type of application much simpler, and to establish some conventions. Currently there is no consensus or default way of structuring ExtJS applications, so anything we can do to move that along will be a step in the right direction! Comments and contributions are more than welcome.

Answer 8

I currently have an extremely large, desktop style app written in ExtJS. It used to run on top of Perl's Catalyst MVC framework, but once the entire View layer was converted to an ExtJS based desktop I started migrating to Ruby on Rails models and controllers. It is equally as fast, if not faster, and easier to maintain and has a much smaller code base.

-Make sure that you set your active record config to not include the root name of the model in the json, so that Ext's JsonStore has no problem reading the records. There is an option on ActiveRecord BASE called include _ root _ in _ json you have to set to false.

-Make sure that you properly define your Application classes in Ext and maximize code re-use and you are going to want some sort of method to clean up unused nodes in the DOM. Javascript performance can be a real pain unless you are using the latest versions of Safari or Firefox 3.1.

-You probably will want some sort of caching method for data on the server to be served to your application in JSON format at the time the page is loaded. This will cut down on the number of round trips via Ajax.

-Definitely make use of Ext's WindowManager and StoreManager objects, or roll your own from Ext.util.MixedCollection

-Develop your code in separate, managable files, then have a build process which combines them into a single file, and then run YUI's compressor or Dean Edwards Packer on it to compress / obfuscate the file. Serve all JS and CSS in their own single files, including the Ext supplied ones.

Answer 9

Ok. I use extjs gxt gwt on many project, and it very easy for develop. But I want to tell you that I built my project with extjs+gwt (gxt), I don't sure about Ruby. link text

Answer 10

You might want to have a look at the Netzke framework that is thought to do just that: facilitate creating complex multi-user/role one-page web-application with the emphasis on component-oriented approach.

The advantages of Netzke are:

• Reusability and extensibility of the code. Once you get your component (both client and server side) made, you can reuse it in any place, combine with other components, or event extend it with inheritance.

• Efficiency. Class for every component is loaded from the server (and evaluated) only once, which saves a lot of time on server-client communication.

• It's open source, and it's in active development. It has live demos and example code.

• It has prebuilt components that you can use straight away without even touching Ext JS (just configure them in Rails)

• It's been used (by its author) for real-life development of a complex logistics application.

Disadvantages of Netzke are:

• The code is young, and the community is very small so far.

• The documentation is scarce, so you would need to look through the code in order to figure how the things are working (another option would be to ask questions on the Netzke google groups)

If you're interested, have a look at the description and design details here: http://github.com/skozlov/netzke/tree/master

Live demo/tutorials can be found here: http://netzke-demo.writelesscode.com/