- web-devel - Haskell.org

More power, more configurable subsites
by Michael Snoyman 25 Jan '11

25 Jan '11

Hi Matt (and the whole web-devel list), Now that Warp is out, and now that the Hamlet decisions have been made, I can (finally) start focusing on yesod-core. Most of the changes we want are already made I think, there are only two open issues that I'm aware of: * Proper request body parsing[1], which is *almost* done. * Disabling sessions for subsites[2] On the second point, I want to broaden our scope: I want to make it possible to run a full WAI application as a subsite. I'll give my current use case: I just wrote a fully-featured wai-app-static application, which takes care of redirecting from "/foo/directory" to "/foo/directory/" and other such things. Now, let's say I have a directory named "my.folder" or a file named "file". In Yesod, the URL cleaning will remove the trailing slash from the former, and add the trailing slash to the latter. However, wai-app-static will do the exact opposite, resulting in an infinite redirect loop. One possible solution to this predicament is to hard-code /static as a special prefix, and not do URL cleaning. But this is a horrible, ugly, evil hack that makes unicorns cry and babies vomit (trust me, I have two kids, you don't want to know what happened hear after I added that commit). What we *really* want is to give subsites much more control over their execution. As the Yesod dispatch functions are written right now, that's not really possible: we do all path cleanup first and then start routing. So here is a possible proposal for how Yesod dispatch should work: * Break up the pathinfo (/static/directory/) into pieces (["static", "directory", ""], the empty string at the end indicates a trailing slash). * Dispatch to subsites only. In other words, we'll keep a list of subsite prefixes separate from other routes, and check those against the unmodified pieces. * If there are any matches, we strip out the relevant prefix from the pieces and pass off control to the subsite. * Subsites created with normal Yesod functions (mkYesodSub) will then go right back into the dispatch function, but now the specific settings for that subsite will be in place. This means that they can control how cleanup is done, whether sessions are on, etc. * You can also write your own subsite code directly and bypass Yesod's dispatch system. This will also make it possible to write a appToSubSite function so that plain WAI applications can be included directly. (I'm hoping that with the release of Warp, there will be more non-Yesod WAI apps out there.) I haven't looked at implementing this yet, but it doesn't sound too hard. I wanted to ask what you thought about how this would interact with your more modular subsite code already. One other thing that comes up as related: Aristid Breitkreuz emailed me and asked why Yesod is a typeclass and not a record type. I gave an answer[3], but I wouldn't mind other people looking into it as well. I'm starting to think about using the records approach on the YesodSubSite typeclass at least and see how that works out. But I have not given this much thought, and this is really an orthogonal- albeit related- question. Michael [1] http://wiki.yesodweb.com/Proper%20request%20body%20parsing [2] https://github.com/snoyberg/yesod/issues#issue/24 [3] http://wiki.yesodweb.com/Yesod%20as%20typeclass%20or%20record

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Re: [web-devel] Yesod. Problem with compile
by Michael Snoyman 23 Jan '11

23 Jan '11

Did you turn on quasiquotes? 2011/1/23 Антон Чешков <acheshkov(a)gmail.com>: > Hello Michael. I have the little problem > i can not compile this: > registrationWidget :: String -> Widget () > registrationWidget s = do > addJulius [$julius|alert("This is Javascript");|] > I got: > Handler/Registration.hs:10:50: parse error on input `;' > I have the same problem when try to add hamlet via $addHamlet. > Do i forget import some stuff module ? > Thanks. > -- > Best regards, > Cheshkov Anton > Phone: +7 909 005 18 82 > Phone: +7 931 511 47 37 > Skype: cheshkov_anton >

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Looking for criticism and comments on web-mongrel2.
by Clint Moore 21 Jan '11

21 Jan '11

After sufficient hand-wringing I finally uploaded web-mongrel2 up to hackage and I'm interested in criticism of my approach. The module itself is terribly simple as it's meant to provide a lightweight layer between an application or framework and Mongrel2, but if nothing else, it's a start. Anyway, the hackage page is at http://hackage.haskell.org/package/web-mongrel2-0.0.2.2 with a link to the github repo.

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Re: [web-devel] [Haskell-cafe] Looking for criticism and comments on web-mongrel2.
by Clint Moore 21 Jan '11

21 Jan '11

On Fri, Jan 21, 2011 at 5:30 AM, Vo Minh Thu <noteed(a)gmail.com> wrote: > The link given on hackage to git is broken, it seems to be > web-mongrel2 instead of haskell-mongrel2. If you click on the latest version the link should be correct. And yes, it's web-mongrel2 - I caught that SECONDS after uploading it to hackage.

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Re: [web-devel] [Haskell-cafe] Looking for criticism and comments on web-mongrel2.
by Michael Snoyman 21 Jan '11

21 Jan '11

On Fri, Jan 21, 2011 at 3:30 PM, Vo Minh Thu <noteed(a)gmail.com> wrote: > 2011/1/21 Clint Moore <cmoore(a)wamboli.com>: >> After sufficient hand-wringing I finally uploaded web-mongrel2 up to >> hackage and I'm interested in criticism of my approach. The module >> itself is terribly simple as it's meant to provide a lightweight layer >> between an application or framework and Mongrel2, but if nothing else, >> it's a start. >> >> Anyway, the hackage page is at >> http://hackage.haskell.org/package/web-mongrel2-0.0.2.2 with a link to >> the github repo. > > Hi, > > The link given on hackage to git is broken, it seems to be > web-mongrel2 instead of haskell-mongrel2. It worked fine for me...

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web-routes-quasi gotcha
by Nubis 21 Jan '11

21 Jan '11

Hi guys, I was just investigating an issue in my yesod app that prevented me from running the devel-server. It was a warning about route patterns overlapping S4M/Server/Controller.hs:33:0: Warning: Pattern match(es) are overlapped In the definition of `parse[awnQ]': parse[awnQ] : "con" : "f" [] = ... parse[awnQ] : "con" : "h" [] = ... parse[awnQ] : "con" : "m" : "list" [] = ... parse[awnQ] : "con" : "m" : "c" [] = ... The issue seems to come up when part of the route is a single character (in this case, f, h and m) like /con/f/ /con/h/ /con/m/list/ I ended up just changing my routes to be more 'expressive' which is fine by me. Haven't looked at the source of the issue yet, I can reproduce it on 0.6.2 but haven't tried 0.6.3 so I apologize in advance if it is already fixed :) Just wanted to get it out here so I don't forget to look into it later (I'm heading home now) Cheers! ----nubis :)

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Directory listings
by Michael Snoyman 19 Jan '11

19 Jan '11

Hi everyone, I'm working on a static file serving WAI app[1], which can either be used from a library, or combined with Warp as a standalone executable. One of its features will be directory listings. Is any interested in designing a directory listing page? Extra points if you can style it using some Haskell colors. Thanks, Michael [1] https://github.com/snoyberg/wai-app-static

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Changes implemented in Hamlet
by Michael Snoyman 15 Jan '11

15 Jan '11

Hi everyone, I wanted to give you all an update on the changes in Hamlet 0.7[1]. So far, the following have been implemented: * Adding angle-bracket syntax * Remove period-delimited variables, and allow qualified functions. For example, $Data.List.sort myString$ * Change forall and maybe to use <-, eg $forall person <- people I haven't tried it on real life code yet, but I have converted the entire Hamlet test suite to use this, and I'm quite happy with the result. Overall, I think things are much more readable. Just for the record: the second item (period-delimited variables) affects Cassius and Julius as well. So now for the last few decisions: * Do we rename maybe to just? I am leaning towards no on this. * For Cassius, do we switch from a whitespace sensitive syntax to brackets? * Do we convert from $my variable$ to #{my variable}. * And if we do this, can we consider #{my (nested call)} and #{my $ nested call} the same? Please see the wiki page[1] for more information on all of these. As far as the I18N note at the bottom: I think we'll be able to release such a feature without introducing any breaking changes. Most likely, a "message" will be a specialization of standard variable interpolation, eg: #?{myI18NMessage} In other words, I'm in no rush to get that feature in the 0.7.0 release, it can wait until 0.7.1. I *do*, however, want to get this Hamlet released soon so that it doesn't hold up Yesod 0.7 any longer: since Yesod 0.6 will not work with WAI 0.3, it also won't work with Warp, and I think a lot of people will want to be able to use Warp soon. Michael [1] http://wiki.yesodweb.com/Hamlet%200.7%20changes

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[Yesod] an API which return Root Relative URL.
by いとうかつとし 07 Jan '11

07 Jan '11

Hi I want an api which return Root Relative URL. I've been developing wiki clone. When a writer select and click an image from photo galary in order to insert a image, click event insert a wiki image link like as "![image_name]( http://localhost:3000/uploaded/1)". But I think this - wiki contents has self Absolute URL - is not good. Is there the API? I want the api, but i remove approot string from Absolute URL, now.

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lazy RESTful Content
by Greg Weber 07 Jan '11

07 Jan '11

lazy and REST seem to go together :) Perhaps this will expose my ignorance of laziness/strictness and isn't at all Yesod specific. I have a handler that can serve html or json. When an html request comes in it still executes the json code. I assume this is because the json code uses liftIO. What is the strategy for avoiding executing the json code?

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