I'm trying to understand what exactly the above (in my question's Title) means? This is taken directly from the SpreeCommerce.com project:
If you’re an experienced Rails developer you may be wondering where your app directory is. Spree actually runs as an embedded Rails app inside of your gem. How do you customize things then? We’ll cover that later in extensions.
Source: http://spreecommerce.com/documentation/getting_started.html
Can someone further explain what exactly it means when a Rails app is run "inside of your gem"
With the gem spree, you can install your application and use it. A lot of application need download complete package to install it. When the gem spree, you don't. So it's more easier to install spree on your server.
The phrase you quote is poorly written and not particularly useful. What you should take away is that Spree is structured different from the majority of Rails plugins.
Typical plugin:
your rails app <-- plugin functionality
A Spree app:
spree rails app <-- your site specific code
Typically, most Rails plugins are installed in the vendor/plugins directory of your Rails app. Some additional functionality is added by classes and modules that you can then reference in your code (subclassing a ResourceController, for instance).
Spree does not work in this way. Because, presumably, there is so much configuration code for Spree, each Spree instance creates a separate Rails app -- one that's missing some of the more important parts of a Rails app (such as the app directory). All of your site specific code goes in the vendor/extensions/site directory. This means you don't have to worry about editing any of the Spree-specific code (since it's all in a different directory) and you can more easily put your own code under source control.
Related
I've got some helper code (monkey patches) I tend to carry around from rails project to rails project via simply copying files or pasting code into the initializers folder.
I think a clean way to deploy different categories of my initalizer code would be to simply add gems to my project Gemfile that would do the equivalent of this for me. I'm not very skilled at creating gems or the deeper side of ruby on rails engineering so I just wanted to know if this were possible before I got started with it.
Yes, this is definitely possible. It should be probably enough to make a simple gem, put your monkey-patches there and require them in the gem entry point (e.g., if the gem is called foobar, then bundler will require lib/foobar.rb by default).
There is a guide on creating gems available in Bundler docs. In case you need to interact with Rails application configuration, you can take a look at Rails Engines.
I'm building a social network and have been using the gem community_engine but have been having trouble implementing the large amount of customization that I need for my app. I figure this will make it easier for me to override and add methods, as well as help me to better understand and learn from the code since I will be able to actually see all of it in action.
So far in my attempt I downloaded the source code, added the default bin directory and config files that were missing, as well ass all the gem dependencies.
What else do I need to do to get the app to work? I realize that there may still be a lot and that it might not be easy to explain, but at the very least is there any sort of documentation out there that might help me understand how to convert the gem to a Rails application?
Heres the community_engine repo: https://github.com/bborn/communityengine
Because this idea may draw some criticism, I'll add that I was originally building the app without any huge plugins accept for devise however I'm running out of time to finish this.
More stuff I've tried:
Moving files to a new rails app, got server to run but encountered many seemingly random errors, fixed a few but more just seem to pop up that I cant figure out:
I also took a look at http://guides.rubyonrails.org/plugins.html but this gem seems to go beyond that.
I would suggest that you clone the gem and begin copying files from the gem into your a new Rails application.
The engine gem probably has a similar structure to a Rails application, so you should be able to move the files from the corresponding folder to the same folder in your Rails root folder.
You may need to move gem files out of modules, change namespaces etc. Relevant folders to look at files you'll want to include might include app/ config/ db/, any gem dependencies in Gemfile or the gemspec file, as well as spec/ or test/.
Beyond that I think there's no silver bullet answer to your question, you're just going to have to work through problems until you have this up and running, and perhaps ask subsequent questions if you hit on an obstacle that you don't get beyond.
I think what you're looking for is a way to hook your Rails Engine into a rails app. The Hooking Into an Application section of the Getting Started with Rails Engines guide should be exactly what you're looking for.
Here are two additional resources on Rails Engines.
A Guide to Rails Engines in the Wild
Rails::Engine - Ruby on Rails API
How do I create a gem project nested inside my current Rails project?
I've got a Rails project with several parts that could easily be gems. I would like to extract these parts into gems but not leave the current Rails project. Creating new source control repos for the gems add additional complexity that project or organization is not ready or able to handle. These complexities will be overcome at some point and I would like to be ready.
So far I can only think of these items.
Relocate code to a single directory root. I'm guessing this would be in the vendor path
Create a <something>.gemspec
Link to the gem in the Gemfile of the Rails app
gem 'my_lib_code', path: 'vendor/my_lib_code'
What else do I need to do? I'm sure I'm missing something important.
If this were a c project I would create another shared library that the make process spits out. Or if this where a c# project I would make a .dll. For Java I would...
I'm sure Ruby can do the same as all the other languages. Something that is a half way step between a normally fully extracted gem and just some code siting in my lib path.
This is a perfectly fine approach for a component-based architecture.
You have a single repository, a single test suite, and a single deployment process, while at the same time you are "forced" to think of clean interfaces and separation of concerns.
Of course if you are planning on sharing this functionality with other projects, an externally hosted (but not necessarily public) Gem would serve better.
Implementation wise, you can get some nifty ideas from Stephan Hagemann's talk at this year's RailsConf: "Get started with Component-based Rails applications!"
I want to customize spree. I have downloaded the source files and modified them. Then I ran install.rb which built and installed gems. The question is: can I see the result of the development without gems building, which takes too much time? I'm newbie to RoR.
Customisations to spree are, in almost all cases, better made in your application rather than by modifying spree's source files. The spree developer docs explain how to do so (see in particular the customisation section):
http://guides.spreecommerce.com/developer/
As a Rails developer I feel a bit stupid asking this question but hopefully I will learn something new and someone can put me out of my misery! In my rails applications I use (other peoples) gems all the time, I also use plugins from the community or my own.
I understand the benefits of use gems over plugins as they are version-able, segmented, system wide, easier to manage and share etc etc but I don't really know how to go about making a gem for my rails apps!?
Do you always start with a plugin and convert it to a gem, I've seen the words 'package it as Gem'. Also the gem I'm thinking of building would be no good in a normal ruby program, it's only useful to rails apps. I'm not even sure if the semantics of that make sense, 'RubyGem' that will only work in a rails application!?
I would like to create a gem (if that's what I should use?) for a discrete piece of functionality for my rails apps. It will need to add a database migration, new routes and provide controllers and views or useful view helpers. I'm know I can achieve this via a plug-in but would just like to know how/why to do it as a 'Ruby Gem'?
To avoid the risk of Over-engineering, I usually start with the feature I need directly into the application. Then, as soon as I need to use the same feature into another project, I check whether it is worth to extract it into a plugin or even a separate application providing an API.
Plugins and Gems are often interchangeable. Gems provides several significant advantages in terms of reusability and maintainability.
On the other side, there are some specific known issue. For instance, a Rails app actually can't load rake tasks defined into a plugin packaged as a Gem.
Almost every Rails plugin can be packaged as a Gem.
For instance, take my tabs_on_rails plugin.
You can install it as a Gem specifying the dependency on environment.rb. Or you can use script/plugin install command as you would expect.
If you want to achieve the same result, make sure to follow the standard Gem layout and provide the init.rb initialization script required by Rails.
Also, you might want to create an install.rb and uninstall.rb file to include the post-install and post-uninstall hooks when the plugin is installed as a standard Rails plugin.
Last but not least, if you package a plugin as Gem you can reuse it in non-Rails projects and provide Rails-specific initializations using the init.rb file. Non-Rails applications will simply ignore it.
If you want to make a plugin for Rails, https://peepcode.com/products/rails-2-plugin-patterns gives you a good start. After that, make the plugin into a gem.
To make a gem, this resource http://railscasts.com/episodes/183-gemcutter-jeweler will be helpful.
As of 2013 you'll want to use Bundler and the following tutorials:
#245 New Gem with Bundler -
RailsCasts
Make your own gem - RubyGems
Guides
Take a look at Jeweler. Jeweler gives you a set of rake tasks to make gem versioning and building very easy.