Thoughts about engines and modules


#1

Hi,

at the moment it is quite difficult to combine multiple Rails apps, e.g.
a forum and a wiki. Neither components nor engines provide a sufficient
level of separation between the parts of the applications to make this
considerably easier, because in the end almost everything becomes mixed
up in the same namespace.

A way to avoid this would be to create all the engine classes (models,
controllers, helpers) inside a module. This would open a whole number of
interesting possibilities:

Controllers/Routing

Controller names of different applications do not collide, you can have
a BooksController both in a wiki and in a book database.

To connect an URL directly to the controller of an engine:
map.connect ‘book/:id’, :module = “wiki_engine”, :controller =>
“books”, :action => “show”

To delegate an URL to the routing of the engine:
map.connect ‘wiki/:url’, :module = “wiki_engine”
…and the “url” part will be processed by the routes.rb of the engine.

Modules

If you need to “talk” to a module of another engine you can write
WikiEngine::Book.find(xyz)

If you want the WikiEngine and the BooksEngine to use the same “User”
model:
WikiEngine::User = BooksEngine::User = MyUserModel

To prevent collision between table names you could assign a table prefix
to an engine or make it use a seperate database connection:
WikiEngine::table_prefix = ‘wiki’

There might be problems I haven’t thought of, and changing Rails to deal
with modules would probably be a lot of work. But on the other hand it
could be a more general solution for both components and engines in the
current form.

What do you think?

Andreas


#2

On Saturday 26 November 2005 08:48 am, Andreas S. wrote:

Hi,

at the moment it is quite difficult to combine multiple Rails apps, e.g.
a forum and a wiki. Neither components nor engines provide a sufficient
level of separation between the parts of the applications to make this
considerably easier, because in the end almost everything becomes mixed
up in the same namespace.

I haven’t kept up with Rails for the last several months, but the last
time I
checked, it also had a problem in that it builds these humongous
$LOAD_PATHs.
This creates another problem in that your ruby filename as well as the
classes are all effectively in one user space. Has anything been done
to
address this?

David