yesod

I know this seems a duplicate to Could not find module `Yesod' , but unlike that user, ghc-pkg list does not show Yesod in its output on my computer, they didn't seem to be using stack (I am, and I'm not sure if that means I don't need to worry about ghc-pkg list ), and additionally, the answer (code) to that question did not help my situation. The Yesod Book has an example that I've been trying to get to work for several hours now. I'll reprint it here {-# LANGUAGE OverloadedStrings #-} {-# LANGUAGE QuasiQuotes #-} {-# LANGUAGE TemplateHaskell #-} {-# LANGUAGE TypeFamilies #-} import Yesod

I'm writing a Yesod application, but it also needs to fork several non-web services. (UDP listeners, TCP listening port, etc.) Where is the correct place to splice in a fork, such that this work seamlessly, regardless of whether my app is running in 'yesod devel' or deployed for production. P.S. I really just want to add a pseudo-Main, which will be forked (at service start) by whichever webserver runs the app through WAI. You should put it in the makeApplication function in the scaffolded Application.hs file. This function will run once for every instance of your web application that is

I have a server and want to deploy my Yesod applications without installing GHC and Cabal. I am not sure if is possible: a Teacher told me that I must first compile Keter in my machine and, after that, put keter executable on the server, though I am not sure how to do that. To build Keter, first you'll need to clone the sources from its GitHub repository . Then you'll need to set up a Haskell build environment and use cabal build or cabal install to build the sources. Personally, I use a Docker container derived from an image based on the following Dockerfile : FROM haskell:7.10.2 RUN apt-get

I am building a survey site in Yesod (0.10) and am getting lost in the types. Here is a simplified version on what I am trying to do. invitation url = do render <- getUrlRender return $ renderHtml [hamlet| <p>Dear foo, please take our <a href=@{ShowSurveyR url}>survey. |] render Another function is going to call this in hopes of getting something that can be passed to simpleMail from Network.Mail.Mime. The above function gives a type error: Handler/Root.hs:404:13: The function `renderHtml' is applied to two arguments, but its type `Html -> LT.Text' has only one This is confusing, because the

For reusability, I want to re-use a widget inside another. For instance, the widget file blogpost.hamlet could contain how a post is displayed, and blog.hamlet could contain the full blog. The following content of blog.hamlet does not work: $forall post <- posts ^{widgetFile "blogpost") So, what is the correct syntax to embed one widget inside another? The Hamlet syntax does not support embedding Template Haskell splices inside of it, which makes the code you're looking to do impossible. Instead, you need to create a helper function in Haskell, e.g.: blogpost post = $(widgetFile "blogpost")

I am working with the default Yesod scaffolding project. I have created a page that displays a simple form to upload files. (The form will likely be created on the client using Javascript.) For brevity, the form has a single file input: <form method="post" action=@{UploadR}> <input type="file" name="myfile"> <button type="submit"> My objective is to process the form data and then upload the file to a web service. I have no trouble processing the form, my concern is interacting with the web service. For example, given the following Yesod handler: postUploadR :: Handler Html postUploadR = do mgr