- web-devel - Haskell.org

Yesod and Tables vs Divs
by Max Cantor 14 Oct '10

14 Oct '10

Just throwing out every feature req that pops into my head now.. Some features of Yesod sort of require tables (fieldsToTable function in the Forms module for instance. Although there is a FieldsToPlain function, you lose a lot when you use it. Given that the trend in web design is away from tables and towards divs+CSS, will this be a problem? Even a generic fieldsWithFxn :: (form element -> rephtml) -> GForm -> GWidget (pardon my pseudo code) might solve this particular problem. Just a thought, let me know if these brainstorms are getting too spammy, I'll stop. Max

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Persistent Feature Request
by Max Cantor 10 Oct '10

10 Oct '10

Just a thought, but the it would be nice if the $persist QQ could also generate some sort of generic migrate function which will migrate all of your tables instead of having to do that manually as in the examples. If you forget a migrate statement, it unfortunately wont raise an error until runtime. As haskellers, we live and die by compile time errors.. Max

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Web wiki page
by John Lenz 09 Oct '10

09 Oct '10

Hi, The past few days I have been investigating the various options for web programming in Haskell and when I first started looking it was pretty confusing. The existing wiki pages weren't really organised to help a newcomer see the various options and which libraries are supposed to work together, since the existing wiki pages basically just list of all the libraries and frameworks. So I edited the Web page on the wiki to list the various options, each of which contain pointers to the various libraries which are meant to work together. I would appreciate help completing the page (any options I didn't list?) since I have only been looking at the various options for a couple of days now. Thanks, John PS: I haven't picked which option I will use for my website yet, still evaluating. But having a list of options is helpful.

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Re: [web-devel] Web wiki page
by John Lenz 08 Oct '10

08 Oct '10

On 10/08/2010 04:59 PM, Jeremy Shaw wrote: > Could you provide a link to the specific wiki page you are referring > to -- I believe there is (or was) more than one page, some better than > others. Just wanted to make sure we are all (literally) on the same > page. > http://www.haskell.org/haskellwiki/Web

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Comments in web-routes-quasi, hamlet, etc
by Max Cantor 05 Oct '10

05 Oct '10

I think this might already have been beaten too death, but there any way of getting a comment syntax (even very simple, anyhting after -- is a comment) into the next version of all the QQs? Would be quite appreciated :) thanks, max

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State of yesod-auth
by Max Cantor 03 Oct '10

03 Oct '10

Is yesod-auth ready for use in development? the 0.0.0 version number is setting off a few alarm bells that there might be a lot of undefined/error calls sprinkled throughout the code and its mostly just type signatures. If it is, I'd like to take a look at it. todah rabah, mordechai

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Re: [web-devel] Getting the http request header in Yesod?
by Rehno Lindeque 27 Sep '10

27 Sep '10

On Sun, Sep 26, 2010 at 2:04 AM, Rehno Lindeque <errantkid(a)gmail.com> wrote: > Thank you, that sounds exactly like what I need. I didn't notice it before! > > Rehno > > On Sat, Sep 25, 2010 at 6:57 PM, Michael Snoyman <michael(a)snoyman.com> wrote: >> On Sat, Sep 25, 2010 at 10:32 AM, Rehno Lindeque <errantkid(a)gmail.com> wrote: >>> I'm looking to detect ajax requests sent to my yesod application using >>> the technique detailed in http://davidwalsh.name/detect-ajax >>> >>> Is it possible to gain access to the request header directly or would >>> yesod require modification to get at it? If someone could just point >>> me in the right direction, I would be grateful. I imagine it would be >>> a function returning GHandler? >> >> You can use waiRequest[1] to get access to the WAI request value, and >> requestHeaders[2] to get the request headers from it. It's very >> convenient to use the OverloadedStrings extensions when dealing with >> the CIByteString datatype[3]. >> >> Hope that helps, >> Michael >> >> [1] http://hackage.haskell.org/packages/archive/yesod/0.5.0.3/doc/html/Yesod-Re… >> [2] http://hackage.haskell.org/packages/archive/wai/0.2.0/doc/html/Network-Wai.… >> [3] http://hackage.haskell.org/packages/archive/wai/0.2.0/doc/html/Network-Wai.… >> > Thanks a lot, this was very helpful! One more question. Is it possible to manipulate the request header when doing a redirect? For example, at one I have (redirect RedirectTemporary $ AuthR LoginR), but "X-Requested-With" isn't being passed through...

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WAI and Apache?
by Kevin Jardine 25 Sep '10

25 Sep '10

I'm interested in implementing web apps in a reasonably standards supporting way and I came across WAI. Is this something that I can run with Apache and mod_fastcgi? Sorry if this is a naive question. Kevin

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Getting the http request header in Yesod?
by Rehno Lindeque 25 Sep '10

25 Sep '10

I'm looking to detect ajax requests sent to my yesod application using the technique detailed in http://davidwalsh.name/detect-ajax Is it possible to gain access to the request header directly or would yesod require modification to get at it? If someone could just point me in the right direction, I would be grateful. I imagine it would be a function returning GHandler? Thanks, Rehno

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On the state of Haskell web frameworks
by Christopher Done 22 Sep '10

22 Sep '10

For what it's worth, I thought I'd throw a simple web app into the mix, hpaste.org: * Address http://hpaste.org/ * Source http://github.com/chrisdone/amelie The notable thing about this application is it's easy to see all the requirements ("small libraries"): 1. CGI/FastCGI: I needed a way to talk to the web, I chose CGI/FastCGI. The CGI library is quite general and small. 2. highlighting-kate: I needed to do syntax highlighting. Notice how it's just a few lines in an isolated module: http://github.com/chrisdone/amelie/blob/master/src/Amelie/Highlight.hs 3. Takusen: I needed to talk to a PostgreSQL database to save/read pastes, just a few lines (for setup) in an isolated module: http://github.com/chrisdone/amelie/blob/master/src/Amelie/DB.hs 4. ConfigFile: I needed a way to store the service's settings in a configuration file. Again, just a few lines in an isolated module: http://github.com/chrisdone/amelie/blob/master/src/Amelie/Config.hs 5. blaze-html/xhtml: I needed a way to build HTML inside my program. 6. formlets: I needed a way to generate and validate forms (e.g. the paste form). 5 and 6 are used in the HTML module: http://github.com/chrisdone/amelie/blob/master/src/Amelie/HTML.hs All of these libraries are perfect, they do one thing and do it well. I just imported them and they did the work for me. You can see also how they are modules in themselves, not interdependent as part of some grand framework. It seems that with good libraries, the architecture of your web app just designs itself. Personally I've always thought the "MVC" approach isn't particularly novel and follows naturally from good design. I'm not saying mine is good design, but without putting much conscious thought towards it, I've ended up with a DB module (model), a Pages module (controller) and a HTML module (view). To make this into the MVC approach, I'd just rename them to Model.hs, Controller.hs and View.hs. The things that I had to implement myself are as follows: 7. URI routing: http://github.com/chrisdone/amelie/blob/master/src/Amelie/Routes.hs How to receive requests and map that into a page + parameters to that page (e.g. paste/pid/30196 -> pastePage [("pid","30196")]), how to *generate* a URL with parameters. And how to generate a *pretty* URL: http://github.com/chrisdone/amelie/blob/master/src/Amelie/Links.hs A URL that maps back to a normal URL (e.g. http://hpaste.org/30196/half_a_proof is actually rewritten by nginx to http://hpaste.org/paste/id/30196) I think there probably are quite a few URI routing libraries out there but I only gave it a cursory glance. 8. Simple template writing. http://github.com/chrisdone/amelie/blob/master/src/Amelie/Templates.hs In fact I found that tibbe already wrote something to do this: http://hackage.haskell.org/package/template but I didn't end up using it for some reason. Maybe because everything has to be Text and I couldn't be bothered littering my code with string conversions all over the place. Turned out I had to do that anyway. Converting between String and ByteString and lazy ByteString and now Text is a real pain but you have to do it because all these different libraries decided to use a particular type. (At least some let you implement a Stringable class.) I will probably eventually just replace the templating code with tibbe's or go the full hog and use HStringTemplate. It's all the same idea, just more or less engineered. I'm interested in your thoughts and ideas. If you have any hpaste-size web applications that you have available online to read that you can maybe summarise and evaluate in the same way I have above, maybe that can spark some interesting discussion. Cheers!

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