I have an idea for a large web application, which in my mind would really be a number of reasonably independent application “components” (?), e.g. forum, blog etc.
It seems to me that it would be nice to open source some of the individual components for others, or myself in the future to use.
Now clearly, I could write a basic forum, make the code available, then copy it across into my large app and extend/integrate it. However, this doesn’t feel very DRY. In an ideal world I could maintain the code in one place and drop it into my larger application.
Rails seems to include engines, which sound like solve my problem but it would appear that what I want to do is a bad idea!
So should I..
a) Just build one large, coupled app.
b) Create a rails forum app (for example), release it, then merge/copy it into my main app
c) Use engines
d) Other…
Cheers,
Adam
That warning is just the standard Uncle Ben Corollary. Paraphrased from “With great power, also comes great responsibility.” to “Just because you can, doesn’t mean you should.”
However, just because there are a number of uses for engines that are bad ideas, that doesn’t mean it is in your case. Blogs and forums are two reasonably independent components that have already been produced as plugins using Engines. You might not even need to make them.
The way I see it, if you’re planning on reusing a functional component that you can feasibly segregate from the rest of the app, then that’s a good enough reason to make it a plugin, whether or not it relies on engines.
My experience is that these plugins grow from existing application code I’ve written. It’s much easier to conceive, write, and test them as part of an application than on their own. Engines being miniature apps, aren’t that much harder to build and test.
In short. Only you can decide which path is best, because you are most familiar with the goals of your app. Before you start have a look at what others have done with engines and plugins. The components you want to build may already exist.
To answer the question, I would probably start by building a single app, and extract out the bits that could be useful in other apps and abstract them into [engine] plugins as they reach maturity.