On 03/28/2012 02:55 PM, Matt Wagner wrote:
On Wed, Mar 28, 2012 at 09:34:58AM +0100, Martyn Taylor wrote:
<snip>
> I actually think that the /conductor URL should be for the UI only
> and /conductor/api for the API.
>
> You could argue that the UI is simply a different content-type that
> our RESTful API supports and therefore all requests are the same but
> content-type is changed. However, I would argue that we treat the UI
> (in html) very differently from other content-types. The UI has
> server state, i.e. sessions (which are not RESTful) and also it
> doesn't only deal with resources. It returns a whole other bunch of
> stuff for layout and styling. This means that resources change
> structure depending on where they are accessed. They should be
> consistent.
This is an interesting point. But I wonder if the answer might actually
be that we're doing something wrong if our controllers are spending more
time on UI setup than on their core function. Session should just be
used for authentication (and stashing flash messages as a UI
convenience), and the only change in resource structure should occur if
you request that it be displayed a different way -- e.g., XML, HTML
table view, HTML "pretty view", or JSON. You should have the same
information each way, just formatted differently. If this isn't the
case, I think we're doing something fundamentally wrong.
The UI should not be
part of the API. Instead it should be built on top
of it. We are lucky in the sense that the API and the UI are
co-located. But this does not mean they are one entity. Adding a
separate html content-type to the API is a separate issue. If people
think it is useful, either for constructing the UI or for REST clients.
Then I'm all for that.
The main difference between the UI and the API is that the UI is
consumed by a user+browser. We add extra information in the controllers
and views and store some session state to add to the user experience,
the same way the CLI does a bunch of stuff on top of the Image
management API to make it user friendly.
Regardless of what you store in the session, if the UI stores state
between requests about particular clients, then it is not stateless.
Statelessness is one of the 6 REST contrainsts.
> In addition to this I would recommend keeping the UI and API methods
> separate (but in the same controller) to keep things cleaner. There
> is a whole bunch of logic that goes towards layout, styling and a
> whole bunch of extra stuff is in there that isn't really relevant (in
> a RESTful API sense). For example, there's probably multiple
> unrelated resource sets in one page.
But the whole problem is that right now the UI and API methods _are_
separate, and this causes needless duplication and divergent code paths,
where the API and UI methods inevitably do things a little differently
with negative consequences. I would argue that, rather than separating
them out, we should merge them and whip them into shape wherever making
a UI controller method work for API calls isn't trivial.
-- Matt
I was not arguing against merging the controllers. What I am saying is
that the UI and the API are separate entities. If you want to serve
them both from the same controllers then fair enough that makes sense.
Helper methods can be written shared by both UI and API etc...
However, what I want to avoid is one massive method that mixes the UI
and API functionality. What I was more envisaging the API methods to
offer a native ruby content type. That the UI methods can use. For
example:
@image = Image.all
when format.xml?
return @images.xml
when format.json
return @images.sjon
else
return @image
end
This way the UI methods can use the API methods in local method calls
and then add whatever extra stuff it needs in order to make the service
usable by a user+browser.
regards
Martyn