- web-devel - Haskell.org

RFC: A standardized interface between web servers and applications or frameworks (ala WSGI)
by Johan Tibell 13 Apr '08

13 Apr '08

Good day hackers, The Python community have been successful in standardizing an interface between web server and applications or frameworks resulting in users having more control over their web stack by being able to pick frameworks independently from web servers, and vice versa. I propose we try to do the same for Haskell. I've written half a draft for a Haskell version of Python's PEP 333 [1]. If you're interested in taking part in this effort please read through the Python spec first (as it is way more complete and you can understand this proposal better by reading it, I've skipped some important issues in my first draft) and then go read the Haskell spec [2]. I'm particularly interesting in feedback regarding: * Doing in this way won't work as it violates HTTP/CGI spec part X, Y and Z (the Python spec takes lots of things from the CGI spec including naming and semantics). * My server/framework could never provide/be run under this interface. * This interface has bad performance by design. * Using a different set of data types would work better. The spec needs to be extended to cover all the corners of HTTP. Some parts need to be motivated better. It is easier for me to motivate things if people would tell me what parts are badly motivated. Note: I'm open to a complete rewrite if needed. I'm not wedded to the current design and/or wording. In fact parts of the wording is borrowed from the Python spec. The parts with bad grammar are all mine. 1. http://www.python.org/dev/peps/pep-0333/ 2. http://www.haskell.org/haskellwiki/WebApplicationInterface -- Johan

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Re: RFC: A standardized interface between web servers and applications or frameworks (ala WSGI)
by Daniel McAllansmith 13 Apr '08

13 Apr '08

On Mon, 14 Apr 2008 11:06:43 Adam Langley wrote: > On Sun, Apr 13, 2008 at 4:59 AM, Johan Tibell <johan.tibell(a)gmail.com> wrote: > > * Using a different set of data types would work better. > > Give that this is Haskell, I'd suggest more types ;) > > HTTP headers aren't just strings and, at the risk of tooting my own > horn, I'll point to the Headers structure in [1]. And it could go further. The use of a given header is often valid only in certain requests or responses. Perhaps sprinkling some phantom types or type classes around could represent that. Daniel

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Fwd: ANN / CFC: minimalistic haskell blogging web application (perpubplat)
by Paul Brown 04 Jan '08

04 Jan '08

Cross-posting from Haskell-Cafe: ---------- Forwarded message ---------- From: Paul Brown <paulrbrown+haskell-cafe(a)gmail.com> Date: Jan 4, 2008 12:43 PM Subject: ANN / CFC: minimalistic haskell blogging web application (perpubplat) To: haskell-cafe <haskell-cafe(a)haskell.org> All -- I've spent some time on cleaning up my hobby blog publishing software and setting up a darcs repository, so I'll throw it out there for criticism or suggestions: darcs get http://datapr0n.com/repos/perpubplat It's running my blog (http://mult.ifario.us) It's relatively lightweight in that it doesn't use a framework but still weighs in at <1500 LOC with comments, but it does rely on the (Thanks, Bjorn!) FastCGI and XHTML combinator libraries. I have some plans for handling comments and the like, but things I'd like to figure out: - Turn the blog data model into a monad. - An idiomatic approach to handling conditional GET and E-Tag, i.e., send a 304 response if things aren't modified. Thanks in advance. -- paulrbrown(a)gmail.com http://mult.ifario.us/ -- paulrbrown(a)gmail.com http://mult.ifario.us/

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[farmand@linagora.com: [Ocsigen] Functional Web Frameworks groups]
by Marc Weber 19 Nov '07

19 Nov '07

Perhaps you are intersted in this as well. Marc W. ----- Forwarded message from Francois Armand <farmand(a)linagora.com> ----- Date: Mon, 19 Nov 2007 07:44:05 +0100 From: Francois Armand <farmand(a)linagora.com> To: ocsigen(a)sympa.pps.jussieu.fr Subject: [Ocsigen] Functional Web Frameworks groups Hi Ocsigen, The world of functional web frameworks seems to be an hot place in these days ! David Pollak of Lift Web (Scala web framework : http://liftweb.net/) has just created a google group to exchange on this topic. It seems to already be some people from Erlyweb (Erlang) and HAppS (Haskel) there, so it really lacks for OCaml advocates ;) Hope to see you there, -- Francois Armand Etudes & Développements J2EE Groupe Linagora - http://www.linagora.com Tél.: +33 (0)1 58 18 68 28 ----------- InterLDAP - http://interldap.org FederID - http://www.federid.org/ Open Source identities management and federation ----- End forwarded message -----

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Re: [web-devel] Scope of this mailing list
by PR Stanley 19 Jun '07

19 Jun '07

For any future queries regarding Web-Devel please feel free to drop me a line at prstanley at ntlworld.com Regards Paul (list owner/moderator)

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Scope of this mailing list
by Neil Mitchell 18 Jun '07

18 Jun '07

Hi I've been developing the tagsoup library, which deals with parsing HTML, which is clearly a web-development task. I'm now wanting to use a mailing list to discuss the further development of tagsoup - I can either set up a separate mailing list, or use this one - which seems to overlap. So would the people in this mailing list rather I just set up a separate tagsoup mailing list (I'm not expecting massive amounts of traffic), or use this one? Thanks Neil [1] http://www-users.cs.york.ac.uk/~ndm/tagsoup/

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Strange HAppS problem (tutorial)
by John Melesky 07 May '07

07 May '07

So, i'm working my way through the HAppS tutorial ( http:// www.haskell.org/haskellwiki/HAppS_tutorial ), and i get to section 3.2. I type in the code, it builds fine, but when i run it, i get the following error: hello: user error (decodeStringM: parsing length field failed @ "") However (and this is the strange part), if i just runghc the .hs file, it all works fine. This is running ghc 6.6, darwinports version, on intel OSX 10.4.9, however i've verified the same behavior on ghc, Audrey Tang's bundle, G4 OSX 10.4.9 (for whatever that's worth). Anyone have any ideas? Anyone run into this before? -johnnnnnnn

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Parse HTTP headers
by Henning Thielemann 10 Apr '07

10 Apr '07

First of all, I want to say that I like Network.HTTP.HeaderName being an enumeration like type because of the advantages that are listed in the HTTP module. HeaderName has a Show instance which shows the header name as the HTTP protocoll requires that. I don't find it good, since I like to copy output values in GHCi back to the GHCi prompt. I'm missing a Read instance or a parsing routine to convert String -> HeaderName. I want to do the following: I download HTML pages from the web which may contain META-HTTP-EQUIV tags. I want to merge the HTTP header, that I got from the web server, with the META information of the downloaded HTML page. I like to merge them in terms of HTTP.Header, not in terms of (String,String) and I also like to have a function like HTTP.findHeader to extract some information from this list. (Currently I'm mainly interested in Content-Type and Content-Language.)

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A light-weight web framework
by Johan Tibell 09 Apr '07

09 Apr '07

Inspired by the ease with which Joe Gregorio put together a framework in Python using some components [1] I'm inspired to create some components of my own so the same thing can be done in Haskell. I'm aiming for creating some thing /really/ simple and I want to start with writing a templating system or a database wrapper. But first, what has been done in this area already already? I'm aware of at least some template like efforts [2]. For the templating system I don't think I want a DSL like approach (ala Lisp with (body (h1 "Foo")) etc. but rather a solution where code and templates are kept separate. Here's a really simple interface. compileTemplate :: Stringable a => a -> Template renderTemplate :: (Show a, Stringable b) => Template -> Map Stringable a -> b Or something along those lines. Compiling the template makes subsequent rendering faster and ByteString adds even more speed. With some templating language like so: <html> <head>...</head> <body> <h1>{{ title }}</h1> </body> </html> 'title' is looked up in the Map when the template is rendered. The other option would be inline Haskell code: <html> <head>...</head> <body> <h1><% postTitle title %></h1> </body> </html> Where 'title' is a record data type. There's also a middle ground like with Django's templates that supports restricted inline code. I guess the restriction is unnecessary in Haskell as we can disallow mutation of values quite easily (?). 1. http://bitworking.org/news/Why_so_many_Python_web_frameworks 2. http://blog.moertel.com/articles/2006/10/18/a-type-based-solution-to-the-st…

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Re: [Haskell] The real Monad Transformer
by Andrew Wagner 03 Apr '07

03 Apr '07

Henning, This link is broken for me... On 4/3/07, Henning Thielemann <lemming(a)henning-thielemann.de> wrote: > > It was argued that people avoid Haskell because of terms from Category > theory like 'Monad'. This problem can now be solved by a wrapper which > presents all the WWW without monads! Start e.g. at > http://saxophone.jpberlin.de/MonadTransformer?source=http%3A%2F%2Fwww%2Ehas… > Of course the tool is written in Haskell, that is, Haskell helps solving > problems which only exist because of Haskell. > Bug reports and feature requests can be tracked at > https://sourceforge.net/projects/parallelweb > _______________________________________________ > Haskell mailing list > Haskell(a)haskell.org > http://www.haskell.org/mailman/listinfo/haskell >

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