How to reuse a rails app - ruby-on-rails

I developed a rails app for a school alumni site.
Now another school wants me to develop a similar site for them.
I want to reuse the app. Data structure will be same but the actual data will be different. Design layout will be similar but design itself will be different.
One option is that I just copy the app and modify it. But in this case, I need to manage 2 apps as they evolve.
Another option will be to make the app generalized and customizable (Database will be separated though). Views will have a lot of a lot of branches.
I could use on database for multiple apps but I am sure it will require a lot of jobs.
Another option will be to move controllers and models to plugins so that 2 apps share them.
Do you have any experience with such a case? If so, can you share it with me?
Thanks.
Sam

This might be a little unorthodox, but if you're using git, you can create two branches
one for the school alumni site
one for the similar site
The root code will stay in the master branch. Your development flow would then be:
branch off the master
make edits
pull edits into master when satisfied
pull the master changes into the branches.
You can continue to locally modify the branches as needed, but you will need to be careful about introducing conflicting edits between master/branch.

If there is any way to avoid the complexity of forking your code into two separate applications you should do it.
Making the application generalized and customizable as you are suggesting moves your one off consulting project into something closer to a standalone product (which might be more profitable).

You'd be surprised how far you can get with different stylesheets, layouts and judicious use of localisation.

2 apps will share:
Models
Helpers
Controllers
They won't share:
Views
I am not sure about database yet.
I may separate views using skin concept like:
app/views/app1/...
app/views/app2/...
I am still thinking about database.

I'm using git submodules and symlinks. There's a submodule to the shared project in Rails.root/shared. Then there's symlinks from app/models to shared/app/models, and so on.

Related

Best practice to create variations of an app?

I've got an application with news, products, printed issues and some other smaller objects which is live and working well.
Now I would like to use this app for two or three other websites that have different content, CSS, views and even some logic needs to be adjusted. What is now the best practice to go for?
What I came up with so far:
Branches: master which stays untouched. Website1, website2 and website3 branched off with respective changes.
Forks: Fork the base app and create 3 more repositories with the changes.
Engine: Turn app into some kind of Engine or alike, mount it in a new app and override everything there.
Keep everything as as and create some configuration file to enable/disable features etc.
Any ideas are highly appreciated!

Share code/configurations/conventions/gems between Rails apps

THE PROBLEM
First a little bit of context: I am currently working as a freelancer, developping webapps using Ruby on Rails. Because I am working solo, the need to optimize my workflow is pretty important.
That's why I have always had the same question since I begun working with Rails:
How can I share code/configuration/conventions/tests between my apps?
More precisely, I want to share:
common gems that I always use, with their configuration
common integration tests, to ensure some conventions
common view helpers, test helpers, extensions to the core classes, javascript/sass partials
common files: .gitignore, git hooks, .eslintrc, configuration files of my CI etc
Some concrete examples of what I need in all my apps:
disable turbolinks by default, to add it later if need be
use javascript instead of coffeescript
use slim instead of ERB
install/configure capistrano
install a CSS framework (bootstrap, bourbon + neat + refills)
So far I don't really have the need to share models nor controllers.
I don't want to share behavior or functional components of the system itself, I am not looking for a micro-services architecture.
I have found that so far when creating new applications, all this setup work does take me a lot of time. Also, I would like to apply it retro-actively to existing apps when I add something new.
I have done quite a bit of research, but I haven't found a lot of answers. Many people are trying to share models, but few people seem to want to share a common ground between all their apps. Finding the right keywords may have been the problem though.
It seems to me that Rails is really good at DRY within an application, not so easy when trying to DRY between applications.
POSSIBLE SOLUTIONS
1 - Rails application template
The solution I am using right now, described in the Rails Application Templates guide, using the same API than the Rails generators described in the Creating and Customizing Rails Generators & Templates guide.
That's the solution used by Thoughtbot, with their popular suspenders gem. In the case of Thoughbot though, they have years of experience to draw from, have many employees and their common setup does not change that much.
Pros:
saves a lot of time when creating a new application
really nice API
Cons:
a lot of duplication: all the apps have the same common code, with the problem of this code getting out-of-sync
not retroactive: useless to add a common feature to already created apps
heavy maintenance work: my current workflow is to go through the git log of my apps once per month, and for each commit that could be common to all the apps I have, add it to the application template, and add it to the other apps manually
So far this solution is not that bad, because I only have two applications. But once I will have more, I will suffer from more and more overhead.
A better solution would be maybe to create a generator/rake task for every common new feature, to be able to apply it quickly to existing apps, and call it directly in the application template for new apps.
I haven't tried it though, and I am not really sure it will work. For example what if I want to propagate a one-line change in an existing common file in all the apps?
2 - Rails Engine
I have tinkered a bit with the Rails Engines to share code.
I have not understood from the Getting Started with Engines guide if I should better use a --full engine or a --mountable one for this specific purpose.
Pros:
once I update the gem version, all the changes are made available to the app
DRY: all the common code is in a unique place (the gem)
Cons:
the gems I would like to share are put in the *.gemspec file, which has not as many features as the Gemfile (from what I understand)
overhead caused by the need to update the version of the gem in all the apps, migrate to the new API of helpers, etc
no way to share non-rails files (.gitignore, git hooks, .eslintrc)
This solution has too many important shortcomings.
3 - Hybrid solution: Rails Application Template + Rails Engine
Maybe the best would actually to use both the above solutions.
In the gem share helpers and tests, in the rails template share the gems, their configuration/files and other files (for git, linters, etc)
It is indeed adding more complexity and overhead...
4 - Use git subtrees
Some people use git subtrees to share folders between multiple webapps.
Cons:
one has to share whole folders, not easy to share everything I would need, in their different target directories in the rails app
seems a bit "hacky" to me
Conclusion
Is there another solution than the ones I mentionned above?
What do you think would be the best way to do it?
How about having a blank "Master" rails app in the git somewhere. With all the settings and configurations you'd like to share. When creating a new app from scratch, you can merge the "Master" into it to apply the defaults. When you have an existing app, same thing, just merge and resolve conflicts as needed.This also gives you the ability to override the merged code if needed to.
Few things I can see wrong with this approach though:
Rails application name could cause a lot of headaches
Any updates could cause merge conflicts
I created a tool to deal with this when working in nodejs projects. But the tool is really just a command line tool so you should be able to use it.
https://github.com/tomasbjerre/dictator-builder
It is a concept with creating a dictator that dictates parts of your code base.

Git - Heroku deploy app that is composed of a couple of git repos

Recently I built an rails app for a local business. They like this app so much that they've gotten a couple of other local businesses interested in having their own version of the app.
Here lies the problem that Im uncertain how to fix. The core business logic behind the app would be the same for these new and future customers(about 80% of the code). Whereas each customer would have their own static pages, as well as their own stylesheets.
Ive thought about multi-tenancy, but these guys are picky enough that it honestly seems easier to build the app function the way they want, as opposed to building around DB stored customer preferences(perhaps I'm wrong here).
I would like configure this application so that I can push changes to the core business logic without overwriting the customer specific portions of the site. Perhaps creating a second repo which only contains the customer specific content.
How do I configure this app/Git repo so that I can personalize the app without creating a bunch of parallel repos?
As Meagar pointed out the solution to this scenario is to encapsulate the core business logic of these applications into a Gem that can be reused later down the road.

Rails: Re-using models, controllers and even views between Rails applications

I have a rails app which contains some fairly generic functionality (eg managing users). I would like to use that common functionality in other rails apps without copying it. The hard part seems to be that this code contains a number of models, controllers and views.
I know that gems and plug-ins allow code to be shared but they seem to apply more to sharing utility and library functionality rather than core parts of an app.
Any advice on how to do this would be greatly appreciated.
We are working with a Rails engine to share functionality between client projects and have gotten quite far with it. The engine contains controllers, models, views, and even routes. It provides core functions needed in each project (access to our in-house content management system) so projects don't have to start from scratch.
Most of the code has been structured in a way that it can be easily extended or overwritten where needed in the projects (mostly by subclassing). It's distributed as gem.
I can't show you code (it's not open-source), but I can point you to some helpful resources:
Rails 3 Plugins - Part 1 - The Big Picture
Rails 3 Plugins - Part 2 - Writing an Engine
Rails::Engine documentation
Plugin Authors: Toward a Better Future
Hope this helps!
Making copies is not always bad. That's why I ask about the reasons you don't want to copy the code.
If you create a 'library', you must ensure that every application will use it in the same manner. Or you have to prepare the 'library' for every possible difference between your applications which use it.
If you share the code, you are adding a dependency to your program. Any change in that shared code will affect more than one application.
Often it's much simpler to copy the code to another application, because then your may apply any modification without thinking about others.
Are you sure that managing users is so generic that you will not make any application-specific changes to it?
What about creating links to the files/directories that have the MVC? That is better than making copies.

Multi domain rails app. How to intelligently use MVC?

Background:
We have app a, b, and plan to add more apps into this same application. The apps are similar enough they could share many views, assets, and actions. Currently a,b live in a single rails app(2.3.10). c will be similar enough that it could also be in this rails app.
The problem:
As we continue to add more apps to this one app, there's going to be too much case logic that the app will soon become a nightmare to maintain. There will also be potential namespace issues. However, the apps are very similar in function and layout, it also makes sense to keep them in one app so that it's one app to maintain(since roughly 50% of site look/functionality will be shared).
What we are trying to do is keep this as clean as possible so it's easy for multiple teams to work on and easy to maintain.
Some things we've thought about/are trying:
Engines. Make each app an engine. This would let us base routes on the domain. It also allows us to pull out controllers, models and views for the specific app. This solution does not seem ideal as we won't be reusing the apps any time soon. And explicitly stating the host in the routes doesn't seem right.
Skinning/themes. The auth logic would be different between the apps. Each user model would be different. So it's not just a skinning problem.
In app/view add folder sitea for sitea views, siteb for siteb views and so on. Do the same for controllers and models. This is still pretty messy and since it didn't follow naming conventions, it did not work with rails so nicely and made much of the code messier.
Making another rails app. We just didn't want to maintain the same controller or view in 2 apps if they are identical.
What we want to do is make the app intelligently use a controller based on the host. So there would be a sessions controller for each app, and perhaps some parent session controller for shared logic(not needed now). In each of these session controllers, it handles authentication for that specific app. So if the domain is a.mysite.com, it would use session controller for app a and know to use app a's views,models,controllers. And if the domain is b.mysite, it would use the session controller for b. And there would be a user model for a and user model for b, which also would be determined by the domain.
Does anyone have any suggestions or experience with this situation? And ideally using rails 2.3.x as updating to rails 3 isn't an option right now.
Devise does exactly this. You would do well to check out its architecture and apply that architecture to your own case.
You will have multiple separate Rails applications. The shared code will be a separate project, perhaps distributed as a gem or at least a separate Git repository. The shared code will include many controller actions and many view templates that are there to be sensible defaults, and which will be overridden in some apps but not in others.
All the custom code for application A will belong in a project solely devoted to containing the custom code for application A. It will be its own fully-functioning Rails application and will depend heavily on the majority of the sensible defaults provided by the shared code in the shared-code project.
I've used the theme support plugin before and dynamically set the theme based on the request uri:
http://mattmccray.com/svn/rails/plugins/theme_support
It will probably need some work to support Rails 2.3.
Update: Looks like there's a rewrite: https://github.com/dasil003/rails-multisite
Sounds like you want to make the 'base' app a plugin and use that in each of your site apps. You can use something like svn-extern so it's automatically updated whenever something changes.

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