April 2012 - web-devel

"Wiki" section of the Yesod doc site
by Michael Snoyman 13 May '12

13 May '12

Hi everyone, I've added a new section to the Yesod doc site: the wiki[1]. This section is intended to be user-writable, so if you have any content you'd like to submit, please go ahead. In particular, this section contains the "Powered by Yesod" page: please add your sites. Unfortunately, the list from the old wiki was lost when my previous VPS died. (All my databases were backed up, I just forgot to backup the Wiki content as well...) Michael [1] http://www.yesodweb.com/page/wiki

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ANNOUNCE: hsx-0.10.1, hjscript-0.6.0, hsp-0.7.0
by Niklas Broberg 23 Apr '12

23 Apr '12

Hi all, I'm pleased to announce the release of the latest versions of the libraries in the Haskell Server Pages suite. Haskell Server Pages enables literal XML syntax to be used mixed with Haskell code (like e.g. PHP), in a sane way (unlike said PHP). In principle the functionality could be used together with any Haskell web framework, but is (currently) best integrated in and supported by Happstack. For this release I owe much to Jeremy Shaw, both for inspiration and for actual patches. There are some grand plans in the pipeline for some more extensive changes to the suite, to shape it up to be worthy of the current exciting state-of-the-art of Haskell web development. Stay tuned! Cheers, /Niklas Specific changes in this release: * In the XMLGen class, the following associated types have been renamed to avoid frequent name clashes, and to better match the intention of those types: XML => XMLType, Child => ChildType, Attribute => AttributeType. * Literal CDATA strings are now given an explicit type signature in the post-processed code. This to avoid ambiguities when OverloadedStrings is enabled. * class XMLGenerator m now has EmbedAsChild m () as another premise. * HSX.Transform now exports a method transformExp :: Exp -> Exp, intended to be used with quasi-quotation. * trhsx no longer performs fixity resolution before transforming, allowing the tool to be used on files using operators with (locally) unknown fixity. * hsp and hjscript updated to work with hsx-0.10.

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Yesod study meeting
by Kazu Yamamoto 23 Apr '12

23 Apr '12

Hello, The Haskell community in Japan has Yesod study meeting. It has just started. We are chatting in Tiwitter with #yesod (in Japanese). --Kazu

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http-enumerator: users?
by Michael Snoyman 22 Apr '12

22 Apr '12

Hi all, I'm wondering if there are still active users out there of http-enumerator. Four months ago I released http-conduit, and since then, my development efforts have gone almost exclusively there. At this point, I'm not longer actively using http-enumerator on any of my projects, and while I've backported any security fixes to http-enumerator, it is otherwise not be updated. I see three possibilities for the future of http-enumerator: 1. Deprecate it in favor of http-conduit 2. Someone else takes over as maintainer 3. Turn it into a frontend for http-conduit, exposing an enumerator interface. This will likely, though not necessarily, result in API breakage I'm curious how others feel on this. If I don't hear anything back on the topic, I'll assume that no one is interested in http-enumerator, and thus will opt for option (1). Michael

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[ANN] blaze-html-0.5
by Jasper Van der Jeugt 21 Apr '12

21 Apr '12

Hello all, I've just released a new version of blaze-html on Hackage. It has some backward-incompatible changes, so feel free to contact me if you run into any trouble. Summary of changes: - Split into blaze-markup and blaze-html - Easy creation of custom HTML elements - Very simple HTML tree manipulation For more details, see: http://jaspervdj.be/posts/2012-04-21-blaze-html-0.5.html Cheers, Jasper

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Happstack Irregular News #1
by Jeremy Shaw 20 Apr '12

20 Apr '12

Welcome to the Happstack Irregular News #1! - 2012-04-20 ======================================================== This is the first issue of the Happstack Irregular News which is published on an irregular basis. Today a bunch of new and updated packages where uploaded to hackage, so it seemed like a good time to make some news! Big thanks to Dag Odenhall, Roel van Dijk, and mekeor.melire for their contributions. Also big thanks to Niklas Broberg, Felipe Lessa, and Gershom Bazerman for being responsive maintainers of their respective packages! Details: NEW: happstack-clientsession ---------------------------- Dag built us a shiny new client-side session data library which stores session data in cookies. It builds on top of the clientsession library from Felipe Lessa and Michael Snoyman, adding the glue needed to make it easy to use with Happstack. The happstack-clientsession library is still new and only lightly tested. So, your feedback and patches are appreciated. The API might still be in flux (unless we managed to get it correct on the first try). hsx-jmacro & happstack-jmacro ------------------------------ Dag and I (mostly Dag) worked on the hsx-jmacro and happstack-jmacro packages. hsx-jmacro now includes a number of methods to embed XML generated via HSX inside javascript generated by JMacro. See the haddock documentation for some discussion and examples: http://www.happstack.com/docs/hsx-jmacro-7.0.1/doc/html/hsx-jmacro/HSX-JMac… Also check out these examples: http://patch-tag.com/r/mae/happstack/snapshot/current/content/pretty/hsx-jm… http://patch-tag.com/r/mae/happstack/snapshot/current/content/pretty/hsx-jm… In the first example you will see these lines: > do let html :: DOMNode > html = <p>Generate javascript from <span class="foo" id="h">HTML & XML</span>.</p> which generate some simple HTML. Then in these lines, that html is added as a child of the main div using the normal javascript appendChild DOM function: > js :: JStat > js = [jmacro| document.getElementById('main').appendChild(`(html)`); > |] Then we have our main handler function, which splices that Javascript into our final HTML document: > handler :: ServerPart XML > handler = defaultTemplate "js-example" () > <%> > <div id="main" /> > <% js %> > </%> So, we saw both HSX being embedded into JMacro and JMacro being embedded into HSX. All the escaping is taking care of automatically for us. And we get to use very familiar looking HTML and Javascript syntax. Dag also made some improvements to happstack-jmacro to prevent global namespace pollution. The 'ToMessage JStat' instance now wraps the javascript inside an anonymous function before it is called. This helps avoid namespace collisions when you import multiple different javascript files (that are generated from JStat). There is also a new 'jmResponse :: ServerMonad m => JStat -> m Response' function which can be used to convert javascript (JStat) into a Response. 'jmResponse' ensures that all identifiers are unique by prefixing them with a hash computed from the rqUri. happstack-server ---------------- Dag and Mekeor added a few new functions to happstack-server. - serveFileFrom checks that the file being served is rooted in a specific parent directory. This is useful for preventing ../../etc/passwd type attacks when a portion of the filename is provided by the user. - combineSafe is a helper function which is used by serveFileFrom and can be reused in your own code - serveDirectory' is exactly like serveDirectory except that it allows you to provide the mime-type mapping function - neverExpires is a helper function that sets an 'Expires' header for as far in the future as is supported by most browsers I also modified happstack-server so that it can be built on platforms with out Template Haskell (such as ARM). happstack-hsp ------------- - analyticsAsync - a helper function that generates the Google Async Google Analytics Tracking Javascript code happstack-lite -------------- Type type-signature for serveFile now expects the mime-type function to be (FilePath -> IO String) instead of (FilePath -> ServerPart String) misc -------------- - a number of packages where updated to accept more recent dependenncies on mtl, transformers, hamlet, etc - Dag provided a bunch of documentation fixes to ixset Other News: =========== HSX ------------ HSX and friends still do not build from Hackage on GHC 7.4. I submitted patches to Niklas, which he has pulled into darcs, but not released on Hackage. However, we then started a long discussion about refactoring HSX so that it no longer depends on HJScript/HJavaScript, plus a bunch of other changes to make HSX easier to install and use. So, hopefully we will have a smaller, better HSX out soon. If you need HSX support on GHC 7.4 right now, you will want to fetch the source from darcs. You can find the darcs repos on patch-tag: http://patch-tag.com/r/nibro Unfortunately, you do not actually want the latest version from darcs, because some of the refactoring work has already begun. In the latest version of HSX, some of the associated types where renamed to avoid name classes. For example XML is now XMLType, Attribute is now AttributeType, etc. You will want to unpull the patches that make those changes. Hopefully this will be straightened out properly on Hackage in the next week. happstack-authenticate ---------------------- I also upgraded happstack-authenticate to the latest version of the authenticate library. The latest version of authenticate dropped support for facebook, so I updated the facebook connect support to use the fb package. Unfortunately, the fb package had not been updated to the latest conduits -- so I submitted a patch for that and a new fb 0.8 was released today! happstack-authenticate is still an 'alpha' package and has not been released on hackage yet. It is available from darcs if you wish to contribute: darcs get http://src.seereason.com/happstack-authenticate/ The major blockers to releasing on hackage are: 1. updating it so that it can take advantage of https:// 2. finishing the cookie code so that expired sessions are deleted 3. reviewing the code and making sure we are not doing anything obviously wrong security wise acme-http --------- In case you missed it, we released acme-http on April 1: https://groups.google.com/group/happs/browse_thread/thread/9b078d23b59a7374… While the announcement and date are a bit jokey, the acme-http server is actually the beginnings of the new Happstack HTTP backend. It is a real server which allows us to investigate some of the low-level performance issues in very small and isolated environment. We will then apply what we learn to the real backend. acme-http delivered 221,693.0 req/s, making it the fastest Haskell web server on the planet. We expect to see a drop when we add things like support for timeouts, etc. But, we also hope to find some ways to increase the performance over the current baseline. web-routes for Snap ------------------- The web-routes package, which provides type-safe URLs, is intended to be usable with a wide range of Haskell web frameworks. Here is a demonstration of how web-routes can be used with Snap without modifying either library (though there is some boiler-plate that could be extracted): https://github.com/stepcut/snap-web-routes-demo Crash Course Updates -------------------- In response to user feedback the acid-state section of the documentation has received some rewritten. There is also a new section on the basics of using Template Haskell: http://www.happstack.com/docs/crashcourse/TemplateHaskell.html#template_has… happstack.com updates --------------------- A lot of work has been going into behind the scenes improvements to the happstack.com website. Those changes should be rolling out soon! That's all the news that's fit to print! (and that I remember!). No extra charge for the typos!

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Happstack authentication and sessions
by Asafe Ribeiro 16 Apr '12

16 Apr '12

How is Session management usually done in Happstack. I found two packages, happastack-auth and happastack-authentication but both seem outdated and no longer manteined (could not even get them to build).

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BlazeHtml: How to write quotation-marks in attributes?
by Morel Pisum 12 Apr '12

12 Apr '12

Hi. How can I write <body onload="javascript:document.getElemByID('q').focus();"> in BlazeHtml? The problem is that single quotes are always converted to HTML. I'd appreciate a quick response. Thanks in advance. -- Morel Pisum

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Fwd: ANN: Selenium WebDriver client for Haskell
by Felipe Almeida Lessa 10 Apr '12

10 Apr '12

[Re-post from Haskell-cafe] ---------- Forwarded message ---------- From: Adam Curtis <acurtis(a)spsu.edu> Date: Tue, Apr 10, 2012 at 7:26 PM Subject: [Haskell-cafe] ANN: Selenium WebDriver client for Haskell To: haskell-cafe(a)haskell.org The first release of the webdriver package has been uploaded to Hackage. Selenium is a test suite that allows you to automate web browsers on a variety of platforms. The webdriver package acts as a client library that speaks Selenium's WebDriver protocol, using a simple monadic interface. This alpha release has received a month of testing through my own usage, and has most of the capabilities of the official Selenium clients, with more to come. Future plans include utilizing the http-conduit and attoparsec-conduit packages for memory efficient JSON parsing, and using the reflection package to safely handle multiple versions of the WebDriver protocol through implicit configurations. For more information, see http://hackage.haskell.org/package/webdriver

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A little trouble upgrading to conduit 0.4.x
by Bardur Arantsson 05 Apr '12

05 Apr '12

Hi all, I'm upgrading various bits and bobs to conduit 0.4.x, but I've hit a little snag with "sourceStateIO". The following function fails to compile: > sourceQuery :: Database -> String -> [SQLData] -> Source IO [SQLData] > sourceQuery database sql parameters = > sourceStateIO > (do > stmt <- SQL.prepare database sql > return (Unbound,stmt)) > (\(_,stmt) -> SQL.finalize stmt) > (\(state,stmt) -> do > -- Bind parameters if necessary. > when (state == Unbound) $ do > SQL.bind stmt parameters > -- Fetch results. > nextResult <- SQL.step stmt > case nextResult of > Done -> return StateClosed > Row -> liftM (StateOpen (Bound,stmt)) $ SQL.columns stmt) All the SQL.xyz bits run in the IO monad. This code runs fine in Conduit 0.2.x, but on Conduit 0.4.x it fails to compile with the following error: src/Data/CQRS/EventStore/Backend/Sqlite3Utils.hs:43:3: No instance for (resourcet-0.3.2:Control.Monad.Trans.Resource.MonadResource IO) arising from a use of `sourceStateIO' Possible fix: add an instance declaration for (resourcet-0.3.2:Control.Monad.Trans.Resource.MonadResource IO) In the expression: sourceStateIO [rest elided; just the rest of the definition of sourceQuery] In an equation for `sourceQuery': sourceQuery database sql parameters = sourceStateIO [rest elided; just the rest of the definition of sourceQuery] I can see that I'm missing an instance, but I can't seem to find a direct instance for MonadResource IO, nor can I tell which indirect instance could get me there. I there some specific import I need to get the necessary instances, or do I need to do something else? Regards,

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