Typically it would look something like this: myApp :: AppConfig -> Application main = do appConfig <- getAppConfig run 3000 $ myApp appConfig Within myApp, you can now access the AppConfig value and use runReaderT to unwrap your MyApp transformer. On Sat, May 16, 2015 at 3:03 PM Alex wrote:

Hello:

I am writing a small application which receives HTTP requests, translates them to JSON, and queues the requests using RabbitMQ.

I created a Monad transformer stack (ReaderT AppConfig IO a) to carry around my application configuration and AMQP connection handle (MVar Connection within AppConfig), but I am having difficulty determining how to integrate it with my Warp application.

The function which is responsible for accepting Requests and returning Responses (app :: Application) needs to call functions which require AppConfig. For example: (sendToRabbitMQ :: RPCRequest -> MyApp ByteString) is a blocking call which requires the AMQP connection handle found within AppConfig, which is why it returns a MyApp ByteString as opposed to a IO ByteString. If I want to call `sendToRabbitMQ' from `app', then the type of `app' needs to change from Application to something else, but I am not sure what that should be.

What's the best way to proceed?

-- Alex _______________________________________________ web-devel mailing list web-devel@haskell.org http://mail.haskell.org/cgi-bin/mailman/listinfo/web-devel