Re: [Haskell-cafe] Using wreq Session handling in a monad transformer stack

withSession doesn't seem to persist anything with this implementation: withInitialState :: (ScraperState -> IO a) -> IO a withInitialState callback = withSession $ \s -> do let initialState = PS { currentOptions = Wreq.defaults , currentHtml = ("" :: LBS.ByteString) , currentCursor = Nothing , currentSession = s } callback initialState runScraper :: Scraper a -> IO a runScraper k = withInitialState (evalScraperWith k) evalScraperWith :: Scraper a -> ScraperState -> IO a evalScraperWith k s = ST.evalStateT k s I looked up the source to withSession, since I don't get why this isn't working. withSession :: (Session -> IO a) -> IO a withSession act = do mv <- newMVar $ HTTP.createCookieJar [] HTTP.withManager defaultManagerSettings $ \mgr -> act Session { seshCookies = mv, seshManager = mgr } http://hackage.haskell.org/package/wreq-0.2.0.0/docs/src/Network-Wreq-Sessio... I did however notice an addition added a few days ago, maybe this is what I need? withSessionWith :: HTTP.ManagerSettings -> (Session -> IO a) -> IO a withSessionWith settings act = do mv <- newMVar $ HTTP.createCookieJar [] HTTP.withManager settings $ \mgr -> act Session { seshCookies = mv , seshManager = mgr , seshRun = runWith } runWith :: Session -> Run Body -> Run Body runWith Session{..} act (Req _ req) = modifyMVar seshCookies $ \cj -> do resp <- act (Req (Right seshManager) (req & Lens.cookieJar ?~ cj)) return (resp ^. Wreq.responseCookieJar, resp) https://github.com/bos/wreq/blob/master/Network/Wreq/Session.hs#L42 On Sun, Nov 16, 2014 at 4:07 PM, Chris Wong wrote:

Hi Cody,

I don't use wreq myself, but withSession [1] is probably what you want.

Here's an example:

withInitialState :: (ScraperState -> IO a) -> IO a withInitialState callback = withSession $ \session -> let initialState = PS { -- ... other options here ... currentSession = session } in callback initialState

[1] http://hackage.haskell.org/package/wreq-0.2.0.0/docs/Network-Wreq-Session.ht...

On Mon, Nov 17, 2014 at 10:08 AM, Cody Goodman wrote:

...

Could I somehow add a Wreq.Session.Session to my monad transformer stack? Should I use something other than Wreq? How would I create a default Session, Wreq doesn't seem to export the constructor. Basically I want to achieve Sessions/cookie handling.

lpaste of my code: http://lpaste.net/114405

my full code (for those who want to view in email):

{-# LANGUAGE OverloadedStrings #-} module Network.Scraper.State where

import Control.Lens ((^.)) import Control.Monad import Control.Monad.IO.Class (liftIO) import qualified Control.Monad.Trans.State.Strict as ST import qualified Data.ByteString.Lazy as LBS import Data.Maybe (fromJust, fromMaybe) import Data.Monoid import qualified Data.Text as T import qualified Data.Text.IO as TIO import Network.Wreq (FormParam (..)) import qualified Network.Wreq as Wreq import Network.Wreq.Session (Session (..), withSession) import qualified Network.Wreq.Session as Sesh import Network.Wreq.Types import Safe import Text.HTML.DOM (parseLBS) import Text.XML.Cursor import qualified Text.XML.Cursor.Generic as CG

data ScraperState = PS { currentOptions :: Wreq.Options , currentHtml :: LBS.ByteString , currentCursor :: Maybe Cursor , currentSession :: Session } deriving (Show)

type Scraper = ST.StateT ScraperState IO

toCursor = fromDocument . parseLBS

initialSt = PS { currentOptions = Wreq.defaults , currentHtml = ("" :: LBS.ByteString) , currentCursor = Nothing -- , currentSession = ... how do I get a Session? Wreq doesn't seem to export this type }

setCurrentOptions :: Wreq.Options -> Scraper () setCurrentOptions o = do scraper <- ST.get ST.put $ scraper { currentOptions = o }

-- getCurrentPage :: Shpider Page getCurrentCursor :: Scraper (Maybe Cursor) getCurrentCursor = do scraper <- ST.get return $ currentCursor scraper

getCurrentSession :: Scraper (Session) getCurrentSession = do scraper <- ST.get return $ currentSession scraper

setCurrentSession :: Session -> Scraper () setCurrentSession s = do scraper <- ST.get ST.put $ scraper { currentSession = s}

setCurrentCursor :: Cursor -> Scraper ( ) setCurrentCursor c = do scraper <- ST.get ST.put $ scraper { currentCursor = Just c }

setCurrentHtml :: LBS.ByteString -> Scraper () setCurrentHtml html = do scraper <- ST.get ST.put $ scraper { currentHtml = html }

runScraper :: Scraper a -> IO a runScraper k = evalScraperWith k initialSt

evalScraperWith :: Scraper a -> ScraperState -> IO a evalScraperWith k s = withSession $ \sesh -> do -- set the current session to the mutable session variable return $ setCurrentSession sesh ST.evalStateT k s

formShortInfo' f = formInfo' where go Nothing = "N/A" go (Just x) = x formInfo = (headMay . attribute "name" $ f, headMay . attribute "action" $ f) formInfo' = (\(x,y) -> (go x, go y)) formInfo

ppTuple :: (T.Text, T.Text) -> T.Text ppTuple = \(x,y) -> "[" <> x <> "]" <> ": " <> y

-- move to ../Spider.hs printFormNames :: Scraper () printFormNames = do c <- getCurrentCursor let c' = fromMaybe (error "No cursor set") c forms = c' $// element "form" formInfo = map (ppTuple . formShortInfo') forms liftIO $ mapM_ (TIO.putStrLn) formInfo

getFormByName :: T.Text -> Scraper [Cursor] getFormByName name = do c <- getCurrentCursor let c' = fromMaybe (error "No cursor set") c return $ c' $// element "form" >=> attributeIs "name" name

get :: String -> Scraper (LBS.ByteString) get url = do r <- liftIO $ Wreq.get url let html = r ^. Wreq.responseBody setCurrentHtml html setCurrentCursor (toCursor html) return html

post :: Postable a => String -> a -> Scraper (LBS.ByteString) post url params = do r <- liftIO $ Wreq.post url params let html = r ^. Wreq.responseBody setCurrentHtml html setCurrentCursor (toCursor html) return html

test :: Scraper () test = do get "https://www.google.com" >> printFormNames _______________________________________________ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe

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