[web-devel] yesod-dynamic

vagif.verdi at gmail.com vagif.verdi at gmail.com
Mon Apr 4 18:35:11 CEST 2011

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 

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

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