yesod

I have the basic "hello world" application setup using wai, and would like to use wai-handler-devel, but am unsure how to go about it and can't find any examples of it in usage on a wai project. {-# LANGUAGE OverloadedStrings #-} import Network.Wai import Network.HTTP.Types import Network.Wai.Handler.Warp (run) import Data.ByteString.Lazy.Char8 () -- Just for an orphan instance app :: Application app _ = return $ responseLBS status200 [("Content-Type", "text/plain")] "Hello, World!" main :: IO () main = do putStrLn $ "http://localhost:8080/" run 8080 app What do I need to do to get wai-handler

I'm trying to write a simplest JSON response from Yesod's handler, but have some really stupid error (apparently). My handler code is this: -- HelloYesod/Handler/Echo.hs module Handler.Echo where import Data.Aeson (object, (.=)) import qualified Data.Aeson as J import Data.Text (pack) import Import import Yesod.Core.Json (returnJson) getEchoR :: String -> Handler RepJson getEchoR theText = do let json = object $ ["data" .= "val"] return json Error is this: Handler/Echo.hs:12:10: Couldn't match expected type `RepJson' with actual type `Value' In the first argument of `return', namely `json' In

I'm trying to implement a server for a turn based game in Haskell. My choice would be to use Yesod for adminstration and meta-information (like, what games a user participates in and such). I'd like to use web sockets to keep the in-game data overhead small. Looking at the ws-chat example, I'm not sure how to get access to the Handler Monad and with it Persistent. It would be perfect to have some bookkeeping-code for the connections wrapped around a "normal" Handler that itself updates the database and informs relevant users. This is how I think it should look like. {-# LANGUAGE QuasiQuotes,

I'm writing my first Yesod app. The application involves the user selecting to view a graph, dynamically generated based on data stored in a DB on the server. I know how to get the user request and create the image on the server's file system, but how do I create a response page presenting it? P.S. As I'm using GnuPlot to generate the image, I only know how to write it as a file to the file system, but If you happen to know how to get the data in memory it'll probably be even better. Thanks, hammar For a file on disk, you can use sendFile in your handler. getImageR = do -- ... save image data

In my Yesod project i have the following route: /api/hide/thread/#Text/#Int ApiHideThreadR GET I want to request it on the client side with javascript: function hideThreadCompletely(threadId, board) { $.getJSON("/api/hide/thread/"+board+"/"+threadId, function(data) { $('#thread-'+threadId).hide(); }); } But i can't use @{ApiHideTHreadR} because Yesod requires it's arguments on compile time. What is the proper solution for this, if i want API URLS to look like api/board/1/1 and not api/board?bid=1&tid=1 ? Keep using manually-defined URL's like "/api/hide/thread/"+board+"/"+threadId ? After some

I use Persistent orm with scotty web framework. I want to get value from db by id. These id are coming to me from GET request There are "get" function that takes "Key Entity" variable and returns "Maybe Entity". I use following code to get value from db k <- keyFromValues $ [(PersistInt64 myOwnIntVarFromRequest)] case k of Left _ -> {-some processing-} Right x -> do t <- liftIO . runDb $ get (x::Key Post) --Post is one of my models case t of Nothing -> {-processing-} Just x -> {-processing-} These code is extremly ugly. But i don't know how to do it better So my question is how obtain variable

Haskell and Yesod newbie here. I've been trying to follow the Integration with Yesod example from the Persistent chapter in the Yesod book (http://www.yesodweb.com/book/persistent). The Sqlite compiles and runs fine it seems. However, I'm trying to use MongDB and am having a hard time getting things to work. Specifically: In the example for sqlite: share [mkPersist sqlSettings, mkMigrate "migrateAll"] [persist| The Yesod book says "Mongo code will use mongoSettings instead." But I can't find it in any of the modules, and the code doesn't compile. So instead, I had to use this instead of

I currently have a Yesod web application that I am developing on NixOS. I am using a default.nix file like described in O'Charles' blog post : { haskellPackages ? (import <nixpkgs> {}).haskellPackages }: haskellPackages.cabal.mkDerivation (self: { pname = "myblog"; version = "0.0.0"; src = ./.; isLibrary = true; isExecutable = true; buildDepends = with haskellPackages; [ aeson bson conduit dataDefault fastLogger hjsmin httpConduit monadControl monadLogger mongoDB persistent #persistentMongoDB persistentTemplate poolConduit shakespeare text waiExtra waiLogger warp yaml yesod yesodAuth yesodCore

I am trying to cabal install yesod on my Windows machine. I have a relatively fresh install of the Haskell Platform. The cabal install failed, reporting that I need the sqlite3 C library in order to install "persistent", a package which Yesod relies upon. cabal: Missing dependency on a foreign library: * Missing C library: sqlite3 So I went to http://www.sqlite.org/download.html and grabbed both the C source and the precompiled binary. I tried using both, to no avail: cabal install persistent --extra-lib-dirs=C:\Path\To\C\Source\Files cabal install persistent --extra-lib-dirs=C:\Path\To\Binary

All the tutorials and references that I could find about Persistent describe in great detail how Persistent can automatically create a new data-type, schema, migration, etc. out of a single definition in its DSL. However, I couldn't find an explanation on how to get Persistent to handle already existing data-types. An example: Suppose I have an already existing Haskell module for some game logic. It includes a record type for a player. (It's meant to be used through lenses, hence the underscores.) data Player = Player { _name :: String , _points :: Int -- more fields ... } $(makeLenses '