conduit

I am trying to construct a Conduit that receives as input ByteString s (of around 1kb per chunk in size) and produces as output concatenated ByteString s of 512kb chunks. This seems like it should be simple to do, but I'm having a lot of trouble, most of the strategies I've tried using have only succeeded in dividing the chunks into smaller chunks, I haven't succeeded in concatenating larger chunks. I started out trying isolate , then takeExactlyE and eventually conduitVector , but to no avail. Eventually I settled on this: import qualified Data.Conduit as C import qualified Data.Conduit

I'm trying to understand the differences between conduit and pipes . Unlike pipes , conduit has the concept of leftovers. What are leftovers useful for? I'd like to see some examples where leftovers are essential. And since pipes don't have the concept of leftovers, is there any way to achieve a similar behavior with them? Gabriel's point that leftovers are always part of parsing is interesting. I'm not sure I would agree, but that may just depend on the definition of parsing. There are a large category of use cases which require leftovers. Parsing is certainly one: any time a parse requires

I'd like to learn the concept, so that I'd be able to understand and use libraries such as machines . I tried to follow Rúnar Bjarnason's talk on machines , but there is too little information, basically just a bunch of data types. I can't even understand what k is in newtype Machine k o = Step k o (Machine k o) data Step k o r = Stop | Yield o r | forall t . Await (t -> r) (k t) r or what's t is and why it's quantified. Or, what's the conceptual difference between conduit -like libraries and machines ? conduit and pipes are both far more mature than machines , but -- that said -- machines is

I have seen people recommending pipes/conduit library for various lazy IO related tasks. What problem do these libraries solve exactly? Also, when I try to use some hackage related libraries, it is highly likely there are three different versions. Example: attoparsec pipes-attoparsec attoparsec-conduit This confuses me. For my parsing tasks should I use attoparsec or pipes-attoparsec/attoparsec-conduit? What benefit do the pipes/conduit version give me as compared to the plain vanilla attoparsec? J. Abrahamson Lazy IO Lazy IO works like this readFile :: FilePath -> IO ByteString where

I use the http-conduit library version 2.0+ to fetch the contents from a http:// URL: import Network.HTTP.Conduit myurl = ... -- Your URL goes here main = do content <- simpleHttp myurl print $ content When running this program, I get this error: *** Exception: TlsException (HandshakeFailed (Error_Protocol ("certificate rejected: certificate is not allowed to sign another certificate", True,CertificateUnknown))) As can be told from the error message, the problem is the inability of Network.HTTP.Conduit to validate the server certificate appropriately (in this case, there seem to be problems in

I am trying to write a simple cat program in Haskell. I would like to take multiple filenames as arguments, and write each file sequentially to STDOUT , but my program only prints one file and exits. What do I need to do to make my code print every file, not just the first one passed in? import Control.Monad as Monad import System.Exit import System.IO as IO import System.Environment as Env main :: IO () main = do -- Get the command line arguments args <- Env.getArgs -- If we have arguments, read them as files and output them if (length args > 0) then catFileArray args -- Otherwise, output