April 2011 - web-devel

Yesod. Persistent. selectOneMany
by Anton Cheshkov 27 Apr '11

27 Apr '11

Michael , please give example how to use *selectOneMany *for join. Thanks. -- Best regards, Cheshkov Anton Phone: +7 909 005 18 82 Skype: cheshkov_anton

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[GSoC] Text/UTF-8: Call for Benchmarks
by Jasper Van der Jeugt 27 Apr '11

27 Apr '11

Hello all, I'm very glad that I have been accepted again this year for the Google Summer of Code [1] program for haskell.org. My project aims to improve the text [2] library by converting it to internally use UTF-8 instead of UTF-16. UTF-8 and UTF-16 both have advantages and disadvantages, which actually makes it a pretty complicated choice. I've written about this a little in my [3] (especially see Tom Harper's master dissertation if you're interested in the subject). To support a decision here on UTF-8 vs. UTF-16, lots of benchmarks will be needed. Hence, this is the first focus of the GSoC project: collecting a large benchmark suite which models real-world usage of the text library. This is why I'd like to ask everyone who has written/knows libraries or applications that use the text library extensively to inform me of these efforts. The reverse dependencies list on Hackage is a good starting point for me but it doesn't point out how popular these packages are and how intensively they use the text library. I will then convert a subset of this code to a benchmark suite using criterion. Open source code means more reliable benchmarks, because I can publish the code I used for them. However, I'm also willing to sign non-disclosure agreements if this means I can try out what effects the changes have on large systems. There's several ways to contact me: you can reply to this thread, or you can mail me privately using `jaspervdj+text(a)gmail.com`. Thanks in advance for any help! [1]: http://code.google.com/soc/ [2]: http://hackage.haskell.org/package/text [3]: http://jaspervdj.be/files/2011-gsoc-text-utf8-proposal.html Cheers, Jasper

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Yesod, Sqlite, Enabling Foreign Key Support
by Anton Cheshkov 27 Apr '11

27 Apr '11

Hi Michael. Please show the way to enable foreign key support from sqlite connection. Now foreign key constrints does not work for sqlite from Yesod. Thanks. http://www.sqlite.org/foreignkeys.html -- Best regards, Cheshkov Anton Phone: +7 909 005 18 82 Skype: cheshkov_anton

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is this a sign of a bad install?
by Michael Litchard 26 Apr '11

26 Apr '11

I had some trouble installing yesod 0.8.0, due to not reading the migration instructions. I did an install in an unconventional way, so am on the lookout for weirdness. I know there have been some problems with "yesod devel", but my problem hasn't been encountered yet, as far as this mailing list goes. Here's the problem I am having. mlitchard@apotheosis:~/repository$ yesod devel yesod: user error (No cabal file found. Please create a package description file <pkgname>.cabal) yesod init seems to work. Could someone shed some light on what is going on here?

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yesod devel strangeness
by Matias Eyzaguirre 26 Apr '11

26 Apr '11

I like the simplicity that 'yesod devel' provides, however it has one fatal flaw. Specifically it doesn't seem to work (or I'm not using it correctly...). When I invoke it it correctly builds and starts serving my application, and when I make changes to the files it depends on it rebuilds the modules that were affected, however it seems to me that it doesn't actually load the changes, it just compiles them and the devel server continues to serve the original application, ignoring my changes. Is this something wrong with my machine specifically? Are others having this sort of trouble? I'm on a macbook pro running OS 10.6.7 with the Haskell Platform 2011.2 installed. Thanks, Matias

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Yesod and 'Order' datatype name
by Anton Cheshkov 26 Apr '11

26 Apr '11

Michael hello . I have got strange ambiguity in yesod. I have in my model the entity with name Order. In compile time i got next error *Conflicting exports for `Order':* * `module Yesod' exports `Yesod.Order' imported from Yesod at Pomoguy.hs:15:1-12 * * `module Model' exports `Model.Order' imported from Model at Pomoguy.hs:22:1-12* * (defined at Model.hs:26:1)* i hide *Order (import Yesod hiding (Order)) *all work fine. Is '*Order*' name reserved by Yesod ? Thanks. -- Best regards, Cheshkov Anton Phone: +7 909 005 18 82 Skype: cheshkov_anton

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Yesod devel error: Yesod: panic! System/Plugins.hs:(84, 14)-(86, 29): Non-exhaustive patterns in lambda
by vagif.verdi＠gmail.com 26 Apr '11

26 Apr '11

Completely fresh install of yesod 0.8 I migrated my application successfully. It builds and works fine. But when trying yesod devel i get this error: yesod: panic! (the 'impossible' happened) (GHC version 7.0.2 for x86_64-unknown-linux): System/Plugins.hs:(84,14)-(86,29): Non-exhaustive patterns in lambda Also cabal gives me following warning on configure: Warning: This package indirectly depends on multiple versions of the same package. This is highly likely to cause a compile failure. package haskell-src-meta-0.3 requires syb-0.2.2 package aeson-0.3.2.4 requires syb-0.3 Not sure if its related to the error in any way, but it does not affect the build, and my executable works fine. Cheers, Vagif Verdi

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plugins and cabal build
by Michael Snoyman 26 Apr '11

26 Apr '11

Hi all, I'm experimenting with using the plugins package for yesod devel server. The basic approach is to use cabal for building the object files, and then load them with plugins. I can get everything to work when I compile with "ghc --make", but I believe name mangling is getting in the way with the "cabal build" route. Can someone give some guidance on how to properly mangle the function names so that plugins can load them? Thanks, Michael

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yesod 0.8 , ghc , panic
by Anton Cheshkov 25 Apr '11

25 Apr '11

Hi all. I decided to try the new version of yesod 0.8 and have been disappointed. I created the scaffolded site and typed *yesod devel. * I was happy. Next I wrote first Handler and ran *yesod devel *again I have been got: *Registering test-0.0.0...* *yesod: /home/anton/.cabal/lib/test-0.0.0/ghc-7.0.3/HStest-0.0.0.o: unknown symbol `__stginit_testzm0zi0zi0_HandlerziOrders_'* *yesod: panic! (the 'impossible' happened)* * (GHC version 7.0.3 for i386-unknown-linux):* * System/Plugins.hs:(84,14)-(86,29): Non-exhaustive patterns in lambda* * * *Please report this as a GHC bug: http://www.haskell.org/ghc/reportabug* * * * * If remove the handler *import* line from *Controller.hs* filr this problem disappeared. * * Have anyone seen it before ? How do i get around this problem. Thanks. -- Best regards, Cheshkov Anton Phone: +7 909 005 18 82 Skype: cheshkov_anton

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wai 0.4.0 uprade for warp 0.8.0 breaks hoogle
by Mark Wright 25 Apr '11

25 Apr '11

Hi, I try to bump warp to 0.8.0 in the gentoo haskell overlay, which requires wai 0.4.0, this breaks hoogle. This is my incomplete and failed attempt to bump wai to 0.4.0 in hoogle: --- hoogle-4.2.1-orig/hoogle.cabal 2011-01-26 22:16:52.000000000 +1100 +++ hoogle-4.2.1/hoogle.cabal 2011-04-20 23:59:18.021501043 +1000 @@ -35,7 +35,7 @@ array, bytestring, containers, directory, filepath, process, random, safe, binary, - parsec == 2.1.*, + parsec >= 2.1, transformers == 0.2.*, uniplate == 1.6.*, haskell-src-exts >= 1.9 && < 1.11 @@ -107,9 +107,11 @@ cmdargs == 0.6.*, tagsoup >= 0.11 && < 0.13, enumerator == 0.4.*, - blaze-builder == 0.2.*, - wai == 0.3.0, - warp == 0.3.0, + blaze-builder >= 0.2 && < 0.4, + http-types >= 0.6 && < 0.7, + case-insensitive >= 0.2 && < 0.3, + wai >= 0.4.0 && < 0.5.0, + warp >= 0.4.0 && < 0.5.0, Cabal >= 1.8 && < 1.11 other-modules: --- hoogle-4.2.1-orig/src/General/Web.hs 2011-01-26 22:16:52.000000000 +1100 +++ hoogle-4.2.1/src/General/Web.hs 2011-04-21 00:03:49.840705869 +1000 @@ -16,6 +16,8 @@ import General.System import General.Base import Network.Wai +import Network.HTTP.Types +import Data.CaseInsensitive(original) import Blaze.ByteString.Builder(toLazyByteString) import Data.Enumerator.List(consume) import qualified Data.ByteString.Lazy.Char8 as LBS @@ -23,13 +25,15 @@ type Args = [(String, String)] +type ResponseHeader = Header --------------------------------------------------------------------- -- WAI STUFF -statusOK = status200 -hdrContentType = fromString "Content-Type" :: ResponseHeader -hdrCacheControl = fromString "Cache-Control" :: ResponseHeader +hdrContentType :: Ascii -> Header +hdrContentType = headerContentType +hdrCacheControl :: Ascii -> Header +hdrCacheControl = headerCacheControl responseOK = responseLBS statusOK responseBadRequest x = responseLBS status400 [] $ fromString $ "Bad request: " ++ x @@ -125,7 +129,7 @@ cgiResponse r = do (status,headers,body) <- responseFlatten r LBS.putStr $ LBS.unlines $ - [LBS.fromChunks [ciOriginal a, fromString ": ", b] | (a,b) <- headers] ++ + [LBS.fromChunks [original a, fromString ": ", b] | (a,b) <- headers] ++ [fromString "",body] --- hoogle-4.2.1-orig/src/Web/Response.hs 2011-01-26 22:16:52.000000000 +1100 +++ hoogle-4.2.1/src/Web/Response.hs 2011-04-20 23:06:21.128254027 +1000 @@ -15,6 +15,7 @@ import Data.Time.Format import System.Locale import Network.Wai +import Network.HTTP.Types(headerContentType) import System.IO.Unsafe(unsafeInterleaveIO) @@ -24,7 +25,7 @@ response :: FilePath -> CmdLine -> IO Response response resources q = do logMessage q - let response x ys z = responseOK ((hdrContentType,fromString x) : ys) (fromString z) + let response x ys z = responseOK ((headerContentType $ fromString x) : ys) (fromString z) dbs <- unsafeInterleaveIO $ case queryParsed q of Left _ -> return mempty --- hoogle-4.2.1-orig/src/Web/Server.hs 2011-01-26 22:16:52.000000000 +1100 +++ hoogle-4.2.1/src/Web/Server.hs 2011-04-20 23:55:34.234388414 +1000 @@ -15,19 +15,18 @@ import qualified Data.ByteString.Lazy.Char8 as LBS import qualified Data.ByteString.Char8 as BS - server :: CmdLine -> IO () server q@Server{..} = do v <- newMVar () putStrLn $ "Starting Hoogle Server on port " ++ show port run port $ \r -> liftIO $ do - withMVar v $ const $ putStrLn $ bsUnpack (pathInfo r) ++ bsUnpack (queryString r) + withMVar v $ const $ putStrLn $ bsUnpack (rawPathInfo r) ++ bsUnpack (rawQueryString r) talk q r -- FIXME: Avoid all the conversions to/from LBS talk :: CmdLine -> Request -> IO Response -talk Server{..} Request{pathInfo=path_, queryString=query_} +talk Server{..} Request{rawPathInfo=path_, rawQueryString=query_} | path `elem` ["/","/hoogle"] = do let args = parseHttpQueryArgs $ drop 1 query cmd <- cmdLineWeb args The compiler error is: [61 of 72] Compiling Web.Server ( src/Web/Server.hs, dist/build/hoogle/hoogle-tmp/Web/Server.o ) src/Web/Server.hs:46:14: Couldn't match expected type `Response' with actual type `Maybe FilePart -> Response' In the return type of a call of `ResponseFile' In the expression: ResponseFile statusOK hdr file In the second argument of `($)', namely `if not b then responseNotFound file else ResponseFile statusOK hdr file' I was wondering how to convert from Maybe FilePart to Response, this looks tricky. Thanks, Mark PS: I have built all of yesod 0.8.0 for gentoo, but we would need to somehow fix hoogle in order for me to apply these changes to the gentoo haskell overlay.

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