# Engines for Rails 2.0 **URL:** \ **Category:** Engines\ **Created:** [November 20, 2007, 2:34pm UTC](https://www.ruby-forum.com/t/engines-for-rails-2-0/120769 "2007-11-20T14:34:34Z")\ **Posts on this page:** 10\ **Page:** 1
**Author:** ![Sven\_F](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/s/b5e925/32.png) [@Sven\_F](https://www.ruby-forum.com/u/Sven_F)\ **Post date:** [November 20, 2007, 2:34pm UTC](https://www.ruby-forum.com/t/engines-for-rails-2-0/120769/1 "2007-11-20T14:34:34Z")
Hi everybody, I’m highly interested in getting a working Engines setup running on Rails 2.0 as soon as possible. I have convinced a customer to use Engines to slice up a huge Rails app but he wants it to run Rails 2.0 I already mailed with Josh F. who wrote the “initial hack” posted here: [http://dev.rails-engines.org/engines-plugin/tickets/267](http://dev.rails-engines.org/engines-plugin/tickets/267) and he kindly send me his entire Engines plugin directory. I can’t seem to get it working though at all. Basically I’ve set up a fresh Rails app and added the Engines::PluginLoader like given in the ticket above. In environment.rb I added below the boot.rb require line: require File.join(File.dirname( **FILE** ), ‘…/vendor/plugins/engines/ lib/engines/plugin\_loader’) And in vendor/plugins/engines/lib/engines/rails\_extensions/rails.rb at the top: require ‘active\_support’ Mongrel will then die with the error: vendor/rails/railties/lib/initializer.rb:193:in `initialize’: wrong number of arguments (1 for 2) (ArgumentError) Not sure what’s wrong here. Looking at the #initialize method of the Engines::PluginLoader that fails here this very much looks like the #initialize method of the Engines Plugin class. Can anybody help me out with this? Probably someone has running Rails 2.0 application set up with Engines and can zip me up the whole application as a starting point? I’m eager to get something up and running by Wednesday evening because I want to present it to a customer who wants to slice up a huge Rails app and Engines seems to be the perfect choice for that. It has to work with Rails 2.0 though. Also … I’d be interested in learning if there’s any work in progress for an official version of Engines for Rails 2.0. Thanks a lot for any pointers! – sven fuchs removed\_email\_address@domain.invalid artweb design [http://www.artweb-design.de](http://www.artweb-design.de) grünberger 65 + 49 (0) 30 - 47 98 69 96 (phone) d-10245 berlin + 49 (0) 171 - 35 20 38 4 (mobile) ---
**Author:** ![Sven\_F](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/s/b5e925/32.png) [@Sven\_F](https://www.ruby-forum.com/u/Sven_F)\ **Post date:** [November 20, 2007, 3:53pm UTC](https://www.ruby-forum.com/t/engines-for-rails-2-0/120769/2 "2007-11-20T15:53:53Z")
Ok, after quite some reading through the Rails 2.0 plugin load process I’ve been able to come up with my own stab at this now. See this patch: [Parked at Loopia](http://pastie.caboo.se/120187) and the top portion of environment.rb here: [Parked at Loopia](http://pastie.caboo.se/120188) I’ve added a PluginLocator (extending the Rails::Plugin::FileSystemLocator) instead of a PluginLoader because that’s the class that is responsible for finding and instantiating plugins in Rails 2.0 Also I’ve changed the Engines Plugin class to extend the Rails::Plugin class. I’ve tried this with Gwyn Morfey’s Macaque engine and it exports the migrations with script/generate plugin\_migration. Also Mongrel starts up and I can access the MacaqueController with the appropriate views etc. I’m still super-curious about what’s necessary to get an official Engines version for Rails 2.0 going. Thanks! Am 20.11.2007 um 14:15 schrieb Sven F.: > I can’t seem to get it working though at all. Basically I’ve set up a > require ‘active\_support’ > Can anybody help me out with this? Probably someone has running Rails > > * * * > > Engine-Users mailing list > removed\_email\_address@domain.invalid > [http://lists.rails-engines.org/listinfo.cgi/engine-users-rails-engines.org](http://lists.rails-engines.org/listinfo.cgi/engine-users-rails-engines.org) – sven fuchs removed\_email\_address@domain.invalid artweb design [http://www.artweb-design.de](http://www.artweb-design.de) grünberger 65 + 49 (0) 30 - 47 98 69 96 (phone) d-10245 berlin + 49 (0) 171 - 35 20 38 4 (mobile) ---
**Author:** ![Sven\_F](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/s/b5e925/32.png) [@Sven\_F](https://www.ruby-forum.com/u/Sven_F)\ **Post date:** [November 20, 2007, 6:55pm UTC](https://www.ruby-forum.com/t/engines-for-rails-2-0/120769/3 "2007-11-20T18:55:26Z")
On 11/20/07, Sven F. [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) wrote: > See this patch: [Parked at Loopia](http://pastie.caboo.se/120187) and the top portion of > environment.rb here: [Parked at Loopia](http://pastie.caboo.se/120188) Hi Sven, Thanks for these patches - I’m definitely keen to get a Rails 2.0 compatible version of the engines plugin released as soon as possible. Until recently I was holding out for some changes to the internal mechanisms used by Rails to load plugins ([http://dev.rubyonrails.org/changeset/8115](http://dev.rubyonrails.org/changeset/8115)), but now that those changes have been accepted I hope to fix up the engines plugin soon. Since Rails’ own “native” plugin loading mechanism has now caught up with some of the enhancements that the engines plugin used to provide (a proper plugin model, loading all remaining plugins with :all, etc) I’m keen to trim down the changes that the engines plugin makes so that the plugin stays as lightweight as possible. If you’re keen to contribute, any investigations as to which parts of the existing codebase (along with your Pastie’d patches) would be greatly appreciated! Thanks again, James ---
**Author:** ![Sven\_F](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/s/b5e925/32.png) [@Sven\_F](https://www.ruby-forum.com/u/Sven_F)\ **Post date:** [November 26, 2007, 12:07am UTC](https://www.ruby-forum.com/t/engines-for-rails-2-0/120769/4 "2007-11-26T00:07:06Z")
Hi James, I’ve now managed to look through the codebase. Basically I’d like to start refactoring from my patch and successively remove duplicate functionality. I’m not sure if it makes sense to partition this up (you asked for investigations as to which parts of the codebase I’d want to touch). As far as I can see there’s: - the Engines’ plugin class could probably be replaced by a module that would be mixed into the Rails::Plugin class - some of the Engine module could probably moved to Rails::Plugin::Loader or to a Engine::PluginLoader that extends from the latter - a dedicated Engine::PluginLocator might be superflous then because the Rails::Plugin class would be used and Rails::Plugin::Loader seems to keep track of the plugin instances (is it accessible though?) - Engines::RailsExtensions::RailsInitializer could be removed (it already is in my patch) These might be fine as they are: Engines::PluginMigrator Engines::RailsExtensions::ActiveRecord Engines::RailsExtensions::Dependencies Engines::RailsExtensions::Migrations Engines::RailsExtensions::PublicAssetHelpers Engines::RailsExtensions::Templates I’ve also looked for test suites in the repository. There seem to be several applications for testing different Rails versions. The “rails edge” application doesn’t seem to have any engines installed, the tests seem to rely on them though (“alpha\_engine” etc.). Am I missing something obvious? Am 20.11.2007 um 18:54 schrieb James A.: > ([http://dev.rubyonrails.org/changeset/8115](http://dev.rubyonrails.org/changeset/8115)), but now that those > greatly appreciated! > removed\_email\_address@domain.invalid > [http://lists.rails-engines.org/listinfo.cgi/engine-users-rails-engines.org](http://lists.rails-engines.org/listinfo.cgi/engine-users-rails-engines.org) – sven fuchs removed\_email\_address@domain.invalid artweb design [http://www.artweb-design.de](http://www.artweb-design.de) grünberger 65 + 49 (0) 30 - 47 98 69 96 (phone) d-10245 berlin + 49 (0) 171 - 35 20 38 4 (mobile) ---
**Author:** ![Sven\_F](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/s/b5e925/32.png) [@Sven\_F](https://www.ruby-forum.com/u/Sven_F)\ **Post date:** [November 20, 2007, 9:38pm UTC](https://www.ruby-forum.com/t/engines-for-rails-2-0/120769/5 "2007-11-20T21:38:36Z")
Hi James, thanks for your quick reply! Am 20.11.2007 um 18:54 schrieb James A.: > Thanks for these patches - I’m definitely keen to get a Rails 2.0 > compatible version of the engines plugin released as soon as possible. This sentence just lifted a ton of weight off my mind 🙂 > Until recently I was holding out for some changes to the internal > mechanisms used by Rails to load plugins > ([http://dev.rubyonrails.org/changeset/8115](http://dev.rubyonrails.org/changeset/8115)), but now that those > changes have been accepted I hope to fix up the engines plugin soon. This stuff is already in Rails 2.0 RC1, isn’t it? Because in [http://dev.rubyonrails.org/ticket/9795](http://dev.rubyonrails.org/ticket/9795) you say that you’ve added a class Rails::Plugin and I’ve already seen this one (and even extended it in that patch). Ok, I think I’ll go and read that stuff up. > Since Rails’ own “native” plugin loading mechanism has now caught up > with some of the enhancements that the engines plugin used to provide > (a proper plugin model, loading all remaining plugins with :all, etc) > I’m keen to trim down the changes that the engines plugin makes so > that the plugin stays as lightweight as possible. Yes, I already wanted to ask about that. Looks like quite some stuff could be dropped from Engines. > If you’re keen to contribute, any investigations as to which parts of > the existing codebase (along with your Pastie’d patches) would be > greatly appreciated! I haven’t used Engines so far and don’t even know all of its features 🙂 That said, I would be happy to contribute as I’m both personally and professionally interested in this approach. I guess I’ll just spend some more time on reading the codebase and then report back. Do you have any suggestions? – sven fuchs removed\_email\_address@domain.invalid artweb design [http://www.artweb-design.de](http://www.artweb-design.de) grünberger 65 + 49 (0) 30 - 47 98 69 96 (phone) d-10245 berlin + 49 (0) 171 - 35 20 38 4 (mobile) ---
**Author:** ![Sven\_F](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/s/b5e925/32.png) [@Sven\_F](https://www.ruby-forum.com/u/Sven_F)\ **Post date:** [December 7, 2007, 8:30pm UTC](https://www.ruby-forum.com/t/engines-for-rails-2-0/120769/6 "2007-12-07T20:30:59Z")
Hi, Did you get anywhere with this? I’d be interested in helping out assembling an Engines plugin for 2.0 ---
**Author:** ![Sven\_F](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/s/b5e925/32.png) [@Sven\_F](https://www.ruby-forum.com/u/Sven_F)\ **Post date:** [December 7, 2007, 10:24pm UTC](https://www.ruby-forum.com/t/engines-for-rails-2-0/120769/7 "2007-12-07T22:24:09Z")
Sven, have you tackled the javascript and css file aggregation/caching stuff? ``` eg: javascript_include_tag(:all, :cache => true) (from DHH's 2.0 ``` release blurb) That’s one of the most exciting features of 2.0 for me, as virtually every engine I’ve written has one (or more!) .js files. I didn’t see any code (or tests) looking at that feature yet. But I’m not much of an engines core hacker yet… 🙂 Again, thanks for the work on this! -Rob ---
**Author:** ![Sven\_F](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/s/b5e925/32.png) [@Sven\_F](https://www.ruby-forum.com/u/Sven_F)\ **Post date:** [December 7, 2007, 10:47pm UTC](https://www.ruby-forum.com/t/engines-for-rails-2-0/120769/8 "2007-12-07T22:47:02Z")
Hi Rob, nope. The first goal is to get Rails Engines working on Rails 2.0 with the functionality it already has on Rails 1.2. This requires some quite extensive refactoring as Rails 2.0 has adopted some of the internal means for plugin loading etc. that Rails Engines provided for Rails 1.2. (Rails Engines for Rails 2.0 will build on this infrastructure and therefor will be much more lightweight.) That said, I’d also love to see that feature in Rails Engines 🙂 Am 07.12.2007 um 22:11 schrieb Rob M.: > > yes, this thread has been continued on the engine-developers list > > > > That said, all the other tests are passing, i.e. the basic > > Am 07.12.2007 um 20:29 schrieb Tony A.: > > > > > - the Engines’ plugin class could probably be replaced by a module > > > > > > several applications for testing different Rails versions. The > > > Engine-Users mailing list > > > > * * * > > > > Engine-Users mailing list > > removed\_email\_address@domain.invalid > > [http://lists.rails-engines.org/listinfo.cgi/engine-users-rails-engines.org](http://lists.rails-engines.org/listinfo.cgi/engine-users-rails-engines.org) > > * * * > > Engine-Developers mailing list > removed\_email\_address@domain.invalid > [http://lists.rails-engines.org/listinfo.cgi/engine-developers-rails-engines.org](http://lists.rails-engines.org/listinfo.cgi/engine-developers-rails-engines.org) – sven fuchs removed\_email\_address@domain.invalid artweb design [http://www.artweb-design.de](http://www.artweb-design.de) grünberger 65 + 49 (0) 30 - 47 98 69 96 (phone) d-10245 berlin + 49 (0) 171 - 35 20 38 4 (mobile) ---
**Author:** ![Sven\_F](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/s/b5e925/32.png) [@Sven\_F](https://www.ruby-forum.com/u/Sven_F)\ **Post date:** [December 7, 2007, 10:01pm UTC](https://www.ruby-forum.com/t/engines-for-rails-2-0/120769/9 "2007-12-07T22:01:52Z")
Hi Tony, yes, this thread has been continued on the engine-developers list (you might want to register there, if you are not, and have a glance the archives). The code has been checked in to the Rails Engines repository here: [http://svn.rails-engines.org/test/engines/rails\_2.0/](http://svn.rails-engines.org/test/engines/rails_2.0/) (This is a complete Rails app in order to get testing going.) Currently there are two tests failing: Arbitrary code mixing: the test on line 34 in [http://dev.rails-engines.org/repository/file/test/engines/rails\_2.0/test/unit/arbitrary\_code\_mixing\_test.rb](http://dev.rails-engines.org/repository/file/test/engines/rails_2.0/test/unit/arbitrary_code_mixing_test.rb) Model/Lib loading precedence: [http://dev.rails-engines.org/repository/file/test/engines/rails\_2.0/test/unit/model\_and\_lib\_test.rb](http://dev.rails-engines.org/repository/file/test/engines/rails_2.0/test/unit/model_and_lib_test.rb) (ignore the note about functional/view\_loading\_test.rb in there) Also, the ActionMailer seems to have changed in Rails 2.0 and this part of Engines is currently just deactivated. That said, all the other tests are passing, i.e. the basic functionality (like model/view/controller loading, routes, migrations etc.) already seems to work. (I also have it being used at a client of mine for test purposes and there haven’t been any problems with the basic stuff.) If you want to get involved with helping here, … I guess that’s appreciated as everybody seems to be pretty busy these days. Am 07.12.2007 um 20:29 schrieb Tony A.: > Rails::Plugin::Loader or to a Engine::PluginLoader that extends from > Engines::RailsExtensions::ActiveRecord > > – > Tony A. > ClickCaster, Inc. > removed\_email\_address@domain.invalid \_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_ > Engine-Users mailing list > removed\_email\_address@domain.invalid > [http://lists.rails-engines.org/listinfo.cgi/engine-users-rails-engines.org](http://lists.rails-engines.org/listinfo.cgi/engine-users-rails-engines.org) – sven fuchs removed\_email\_address@domain.invalid artweb design [http://www.artweb-design.de](http://www.artweb-design.de) grünberger 65 + 49 (0) 30 - 47 98 69 96 (phone) d-10245 berlin + 49 (0) 171 - 35 20 38 4 (mobile) ---
**Author:** ![Sven\_F](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/s/b5e925/32.png) [@Sven\_F](https://www.ruby-forum.com/u/Sven_F)\ **Post date:** [December 10, 2007, 9:59am UTC](https://www.ruby-forum.com/t/engines-for-rails-2-0/120769/10 "2007-12-10T09:59:07Z")
Hey… Checkout the toolbawks\_packer plugin I wrote up. It allows you to do just that bug even better. Planning on moving more towards a bundle\_fu approach with a block wrapper, but right now it works awesome for me. Beta software so far, but will do the trick never the less 🙂 Also, I have dropped in bundle\_fu in existing apps as well, and it works pretty decently as well. With that said, we don’t really need it in Engines directly per-say, as additional options are available, but nice if it was there. Although Rails 2.0 doesn’t really do the job that well, or at least as well as the toolbawks\_packer and bundle\_fu plugins do. Nathaniel.