January 2011 - web-devel

[Yesod][Auth][OpenId]
by いとうかつとし 12 Feb '11

12 Feb '11

Hi, I have a question. OpenId plugin in yesod-auth 0.2.0.3 don't support OP identifier? for example, i try japanese SNS mixi.jp, Claimed identifier: https://id.mixi.jp/<myid> => success and login my developed site. OP identifier: https://mixi.jp => fail!! I success to login to mixi, but mixi say the error message: `Given OpenID is not yours, your OpenID is http://id.mixi.jp/<myid>. confirm and try again.' the mixi's developer center say mixi 's OP identifier is https://mixi.jp. anyone success to login by using OP identifier? regards.

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plugins and internal error: stg_ap_v_ret
by Michael Snoyman 01 Feb '11

01 Feb '11

Hi all, I'm trying to convert wai-handler-devel to use plugins instead of hint, but cannot even get some basic usages to work properly. I've put together a minimal example that loads a WAI application from a separate file and runs it, but this immediately causes the program to crash saying: loader: internal error: stg_ap_v_ret (GHC version 6.12.3 for i386_unknown_linux) Please report this as a GHC bug: http://www.haskell.org/ghc/reportabug Is this an actual bug in GHC, or am I misusing the plugins package? The two source files: MyModule.hs {-# LANGUAGE OverloadedStrings #-} module MyModule where import Network.Wai import Data.ByteString.Lazy.Char8 () myapp _ = responseLBS status200 [("Content-Type", "text/plain")] "myapp" loader.hs import System.Plugins.Make import System.Plugins.Load import Network.Wai.Handler.Warp (run) main :: IO () main = do MakeSuccess _ obj <- makeAll "MyModule.hs" [] LoadSuccess _ app <- load_ obj [] "myapp" run 3000 app Thanks, Michael

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http-enumerator and redirects
by Aristid Breitkreuz 31 Jan '11

31 Jan '11

Hi, Michael Snoyman plans to expose http-enumerator's HTTP redirect logic in a public API. For this reason, we had a short discussion over e-mail, which he asked me to resume here. The problem at stake is how to deal with redirects in the case of POST requests, especially with streaming request bodies (streamingHttp as of 0.3.1). Currently, the same HTTP method is always used, but this is not really the correct course of action. RFC 2616 mandates that for 301 and 302 responses, the request should be retried with the same HTTP method (side problem: restarting streams?). 303 triggers a GET, however, and I'm not sure about 304-307. RFC 2616 also mentions that most existing clients actually unconditionally use GET for 302 responses, which we should take into account. Michael proposed always forcing GET, but I'm not sure if this is correct either, because for example 301 clearly demands POST to be re-used. So, the question is, how do we solve these problems? Should there be an element of configurability? Aristid

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yesod's hamletFileDebug
by Rafael Cunha de Almeida 29 Jan '11

29 Jan '11

Hello, I'm new to yesod and haskell web development in general. I read a bit about yesod and it looked nice. I thought it was really cool that I'd be able to view my changes to a template without recompiling, something I've always found very appealing in interpreted language's frameworks. However, after running yesod it created a Setting.hs file which uses H.cassiusFileDebug and H.juliusFileDebug for the purpose of dynamically generating such files, but hamlet files doesn't seem to work that way. Why was that changed? Am I to expect such feature will come back in the future? Or is already possible it just need to be set somewhere else? []'s Rafael

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Hoogle Advice
by Neil Mitchell 28 Jan '11

28 Jan '11

Hi, I am the author of Hoogle (http://haskell.org/hoogle/) a Haskell API search engine, that is usually used through a web interface. I'm not an expert on website programming in Haskell, and I'm not a server admin by any means. Currently the web side of Hoogle can run in two modes - as a CGI binary (as deployed on haskell.org) or with "hoogle server" which starts its own server. I wrote both the CGI interface (see http://code.haskell.org/hoogle/src/General/Web.hs) and the server (see http://code.haskell.org/hoogle/src/Web/Server.hs) myself. I imagine there is something in the web devel community that I should be using instead? If so, what is it, and how do I use it? I have a few requirements: * I have to be able to integrate it with haskell.org (which probably runs Apache?). * I also want to be able to run it as a server where the hoogle binary runs the server. * If I could get log/email messages whenever serving a page caused an exception, or took longer than a certain threshold, that would be great - but isn't necessary. * I'd like to log all queries run, and in particular how long they take, so I can investigate performance issues. Thanks for any advice you may be able to give, Neil

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Automatically making every Cereal.Serialize instance of PersistField - bad idea?
by Max Cantor 28 Jan '11

28 Jan '11

With a bit of code, you can save a lot of effort if you add new types to Persistent: instance Cereal.Serialize a => PersistField a where toPersistValue a = PersistByteString $ Cereal.encode a fromPersistValue (PersistByteString b) = Cereal.decode b fromPersistValue _ = Left "bad type for cereal encoded data" sqlType _ = SqlBlob isNullable _ = False BUT, this requires UndecidableInstances. Is this a bad idea? mc

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Persistent Feature Suggestion - append only tables
by Max Cantor 28 Jan '11

28 Jan '11

Just a thought, but if there was a way to annotate tables in Persistent as append only, that would open to the door to some cool, application-side caching in persistent. Note that simply omitting "Update" from the table definition is insufficient since the row could still be deleted. Michael et al., what do you think? Max

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[Yesod][hjsmin] Could not handle UTF-8 literal in julius file?
by いとうかつとし 28 Jan '11

28 Jan '11

Hi I write julius file like this. (snip) var fs = $('<fieldset><legend>Recent Changes</legend></fieldset>'), ul = $('<ul/>'); $('#recent-changes').append(fs.append(ul)); (snip) This works good. But,... (snip) var fs = $('<fieldset><legend>最近の更新</legend></fieldset>'), // Japanese UTF-8 ul = $('<ul/>'); $('#recent-changes').append(fs.append(ul)); (snip) This script(with UTF-8) transform legend text to unreadable string. Then, I try to insert "debugger;" statement in order to disable to hjsmin, This try is success and make readable. Could you confirm this?

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ANNOUNCE: WAI 0.3.1, Warp 0.3.1, wai-app-static 0.0.0 and warp-static 0.0.0
by Michael Snoyman 27 Jan '11

27 Jan '11

Hi everyone, Firstly, after some feedback, I'm releasing some point updates for WAI and Warp. They fix some documentation issues, add some status aliases, make it possible to handle exceptions more easily, and make things more responsive on Windows. Next, I'm releasing two new packages: wai-app-static is a static file serving application for WAI. It handles all of your basic needs in this department: * Proper 301 requests to fix trailing-slash issues for folder vs directory. * Directory listing support (if turned on), including a default listing function that uses Haskell colors and a Haskell logo in the corner. Thanks to Happstack for the basis of this code. * Directory index support (eg, index.html, index.htm), again configurable. * Mime type lookups. Thanks to Snap for this table. warp-static is simply a standalone executable that runs wai-app-static on the Warp webserver. The executable name is warp. I know I personally have needed such a light-weight web server at work a few times, so if nothing else, putting it on Hackage is a convenience for me :-). I hope people find these useful. Don't expect the performance to beat nginx, but it is still quite good. if there are any other features requests on any of these packages, let me know. Michael

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Re: [web-devel] richer client experiences
by Greg Weber 26 Jan '11

26 Jan '11

Thanks for the great extra info on JMacro. I think haskellers would enjoy hearing about it and how you use it as a blog post. Hi! Author of JMacro here. You're right that JMacro has a few less features than CoffeeScript. In particular, it lacks pattern matching. Outside of that, however, most CoffeeScript features are to make CoffeeScript more rubylike in syntax. Haskell-style anonymous lambdas coupled with whitespace function application on their own, however, suffice to allow exceedingly Haskell/ML-like code. JMacro can be used as a nicer syntax for JavaScript, but the big win is that it is a better way to *generate* JavaScript -- in particular via hygiene and a shared namespace with surrounding Haskell code. So bear in mind also that JMacro syntax is infinitely-extensible in the sense that you can not only write JavaScript combinators in JMacro, but Haskell combinators which produce JMacro that can be spliced directly back into a block of code. Jeff and I have, for instance, written a tiny set of infix combinators for chaining jQuery selectors. coffee-script isn't designed to give javascript a ruby-like syntax. It is designed to add useful language level features and get rid of superfluous syntax, which Ruby and haskell also try to do. Maintaining a certain amount of javascript compatibility makes it look more like Ruby and less like Haskell. But there are definitely influences from other languages. For example, it uses layout syntax instead of an 'end' keyword (or brackets) in ruby. You can use groovy's existential operator. >From looking at the jmacro README I am slightly confused as to what syntaxes are required, and which are optional, but it seems like the following features are in coffee script but not jMacro * no need for the var keyword, scope is intelligently taken care of. * no need for semi-colons * no need for parentheses around conditionals for ifg * list comprehensions (as in python), an extremely useful feature. * removal of brackets and commas for objects * argument splats * single line conditionals * ranges * class/super class conveniences * 'this.' aliased to '@' * multi-line strings * string and regular expression variable interpolation There are other things that might be missing/different, but I can't tell because they aren't documented, such as: * removal of triple-equal- double equal acts as triple equal (or is this in just the lambda syntax?) Another feature of JMacro as opposed to CoffeeScript is that almost all valid JavaScript code is *also* valid JMacro. So you can take a code-sample or snippet from the web and place it directly into your application, refactoring it into a more functional style incrementally and at whatever pace you want. CoffeeScript allows for "escaping" into raw javascript, but that's in my opinion a much weaker alternative. This is also true of coffeescript, but to a lesser extent. Function syntax must be converted, and the var keyword removed. After that, plain javascript should works, and there are usually many improvements that can be made incrementally. While this provides some downside, it also provides upside- there is one unified function syntax that is as convenient as the haskell anonymous lamba syntax instead of 2 different function syntaxes with different rules. I really like what you have done with jMacro. My previous comments were really directed to thinking about it in a different context. I think we just need to clarify that these are different tools for different jobs. For the goal of writing javascript instead of generating it, coffee-script holds a lot of advantages over jMacro. For the goal of generating javascript from haskell (which you are using it for), jMacro seems like the perfect tool, and I will definitely look into using it for that purpose in the Yesod framework or my Yesod applications. Greg Weber

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