[web-devel] yesod-dynamic

Michael Snoyman michael at snoyman.com
Mon Apr 4 18:41:55 CEST 2011

A subsite needs to use the exact same approach of multi-pieces in
order to achieve dynamic routing. So it's not really an either/or
situation. The only thing subsites do is package up a set of
routes/handlers that can be used in other sites.


On Mon, Apr 4, 2011 at 7:35 PM,  <vagif.verdi at gmail.com> wrote:
> I think we can have our cake and eat it too :)
> The functionality of dynamic routing, coupled with type-safe urls is already
> in yesod: Subsites! Unfortunately they are not documented. That's why i
> personnaly do not use them. I simply cannot figure out how.
> And yesod-auth can give access to entire subsite, same way as dynamic routing
> does.
> On Monday, April 04, 2011 04:21:20 AM Michael Snoyman wrote:
>> Hi all,
>> There's an inherent difference in how Yesod handles routing, by default,
>> and how Happstack/Snap handle routing, by default. (Apologies if I am
>> mistaken in my understanding of the latter.) Yesod is built in with the
>> concept of type-safe URLs. This forms the basis of routing in Yesod: the
>> list of path segments is first converted to a type-safe URL value, and
>> then the appropriate handler is chosen from that. On the other hand,
>> Happstack/Snap both allow you to perform routing directly on the path
>> segments.
>> What many people don't realize is that it's entirely possible to do
>> segment-based routing in Yesod. I don't recommend the practice in general,
>> since it defeats a lot of the type safety Yesod gives you. However, in some
>> situations it's a necessity. For example, yesod-auth allows arbitrary
>> authentication plugins, which would not mesh up well with type-safe URLs.
>> The trick to bypassing the type safety is to use multi-pieces. Instead of
>> describing how this is possible, I will merely point to an example:
>> https://gist.github.com/884802
>> The Yesod.Dynamic module defined there is really a general way to allow
>> Yesod routing based on path segments. Since the question has come up a
>> number of times in the past, I'm curious if people would want this
>> available on hackage. I'm sure a nice set of routing operators would be
>> useful here as well.
>> Michael
> _______________________________________________
> web-devel mailing list
> web-devel at haskell.org
> http://www.haskell.org/mailman/listinfo/web-devel

More information about the web-devel mailing list