I've configured logging like so:
import System.Environment
import System.Log.Logger
import System.Log.Handler (setFormatter)
import System.Log.Handler.Simple (streamHandler)
import System.Log.Formatter
import System.IO (getLine, stdout)
main = do
stdOutHandler <- streamHandler stdout DEBUG >>= \lh -> return $
setFormatter lh (simpleLogFormatter "[$time : $loggername : $prio] $msg")
updateGlobalLogger "Linker" (setLevel DEBUG . setHandlers [stdOutHandler])
infoM "Linker" "Hello world!"
Unfortunately, every time I use infoM (or any logging function), I get duplicate lines, e.g.
infoM "Linker" "hi there"
produces:
hi there
[2016-12-05 20:23:10 GMT : Linker : INFO] hi there
I thought setHandlers removed other handlers first.
I want just the lines that are formatted, not the "normal" format ala putStrLn etc.
I found error in your program. Actually, it was in your first code, I just didn't pay enough attention to it :(
All you need is to replace logger name with rootLoggerName in
updateGlobalLogger "Linker"
to
updateGlobalLogger rootLoggerName
This did the trick for me. I don't know what happens when you're not initializing with root logger but now it will at least work.
Also, if you're using stack and don't mind using github projects then you may wish to consider using our logging library (it is not currently on hackage) which is a wrapper around hslogger which adds some juice to it (like coloured logger names and more):
https://github.com/serokell/log-warper
Related
I want to parse a LaTeX-File using Pandoc and output the text, like this:
import qualified Text.Pandoc as P
import Text.Pandoc.Error (handleError)
tex2Str = do
file <- readFile "test.tex"
let p = handleError $ P.readLaTeX P.def file
writeFile "A.txt" $ P.writePlain P.def p
writeFile "B.txt" $ file
While the encoding in file B.txt seems to be "right" (i.e. uft-8), the encoding in file A.txt is not correct.
Here the respective extracts of the files:
A.txt:
...
Der _Crawler_ läuft hierbei über die Dokumentenbasis
...
B.txt:
...
\usepackage[utf8]{inputenc}
...
Der \emph{Crawler} läuft hierbei über die Dokumentenbasis
...
Anyone knows how to fix this? Why does Pandoc use the wrong encoding (I thought, it uses utf-8 by default)?
Update:
I got a (partial) solution: Using the readFile and writeFile-Functions from Text.Pandoc.UTF8 seems to fix some of the problems, i.e.
import qualified Text.Pandoc as P
import Text.Pandoc.Error (handleError)
import qualified Text.Pandoc.UTF8 as UTF (readFile, writeFile)
tex2Str = do
file <- UTF.readFile "test.tex"
let p = handleError $ P.readLaTeX P.def file
UTF.writeFile "A.txt" $ P.writePlain P.def p
UTF.writeFile "B.txt" $ file
However, I still didnt get the clue what the actual problem was, since both Prelude.readFile and Prelude.writeFile seem to work uft8-aware...
I'm trying to make the chat example from the Yesod book working in the scaffolding site.
I think I've corrected almost all I had to correct, but all of that is completely new to me (it's my first "real" Haskell project) and I'm not very confident in all my modifications; moreover, I'm really stuck at the point 7. Could you comment all the following points if necessary, and helping me for the 7. (in bold some questions/remarks)?
Copy/paste the Chat.hs and Chat/Data.hs in the root of my site,
add import Chat as Import and import Chat.Data as Import to Import.NoFoundation,
add import of IO, Bool, return, Maybe(Nothing), ($) in Data.hs, since the extension NoImplicitPrelude is on Seems very clumsy... Do we have to import all the standard operators on each new file?
in Fundation.hs, add getChat in the App record (after appHttpManager and appLogger)
in Fundation.hs, add YesodChat instance for App: I had to modify the getUserName on the Just uid case (in the original example of Chat, it was just Just uid -> return uid):
Just uid -> do
muser <- runDB $ get uid
case muser of
Nothing -> error "uid not in the DB"
Just user -> return $ userIdent user
This seems very long and nested... Can we do better?
In Fundation.hs, add chatWidget ChatR after the line pc <- widgetToPageContent $ do in the defaultLayout definition.
Now, I have the following warning :
Application.hs:60:36: Warning:
Fields of ‘App’ not initialised: getChat
In the expression: App {..}
I think I have to write something like getChat <- newChan >>=Chat after the appLogger <- newStdoutLoggerSet defaultBufSize >>= makeYesodLogger and appStatic <- ... in the makeFundation definition, but the type doesn't match. I'm a totally lost here, I don't really understand how this function makeFundation works.
You actually got almost the entire way there. I think you just need to change the line to:
getChat <- fmap Chat newChan
Alternatively, if you're not familiar with he fmap function yet, you can use do notation and get:
chan <- newChan
let getChat = Chat chan
I'm having an issue with the Scotty web server right now - rescue isn't working for unfound parameters - I'm still getting a 404 with the following code:
post "/newsletter/create" ( do
(param "subscriber[email]") `rescue` (\msg -> text msg)
formContent <- param "subscriber[email]"
text $ "found! " ++ show formContent )
I can see that when I just use params instead, my data is there, and indexed with "subscriber[email]". Is there something going on with [ escaping? Any help with this would be tremendous.
With some cleanup I got it to work:
{-# LANGUAGE OverloadedStrings #-}
import Web.Scotty
import qualified Data.Text.Lazy as TL
main = scotty 3000 $ do
post "/newsletter/create" $ do
formContent <- (param "subscriber[email]") `rescue` (\msg -> return msg)
text $ "found! " `TL.append` formContent
I made a bunch of modifications, but the key point was that rescue is used as a wrapper around param, not to change any internal state, hence you shouldn't call it twice. The square brackets didn't cause me any trouble.
I'm probably just overlooking something basic in the documentation of http-client-tls and tls, but: how can I establish an HTTPS connection to a server and only accept one particular certificate, specified by me, that is potentially not in the system certificate store?
I see that this is an old question, but I just spent some time writing code to do this and figured I'd post it here for posterity... and in the hopes of getting some code review from the community. Snoyman's comment is helpful, but there are so many code interdependencies here, and X.509 and TLS are so boil the ocean, that it's hard to debug and to know for sure that you're not screwing something up without digging pretty deep into the various libraries. I figured a more complete explanation with working code was in order.
Anyways, here's what I've come up with (this is a stack script so you can run it easily yourself) --
#!/usr/bin/env stack
{- stack --resolver lts-7.16 runghc -}
import qualified Data.ByteString as B
import Data.ByteString.Lazy (ByteString)
import Data.Default.Class (def)
import Data.String (fromString)
import Data.X509.CertificateStore (CertificateStore, readCertificateStore)
import Network.HTTP.Client (httpLbs, newManager, ManagerSettings)
import Network.HTTP.Client.TLS (mkManagerSettings)
import Network.Connection (TLSSettings(TLSSettings))
import qualified Network.TLS as TLS
import qualified Network.TLS.Extra.Cipher as TLS
import System.Environment (getArgs, getProgName)
managerSettings :: CertificateStore -> ManagerSettings
managerSettings store = mkManagerSettings settings Nothing
where settings = TLSSettings params
params = (TLS.defaultParamsClient "" B.empty) {
TLS.clientUseServerNameIndication = True
, TLS.clientShared = def {
TLS.sharedCAStore = store
}
, TLS.clientSupported = def {
TLS.supportedCiphers = TLS.ciphersuite_default
}
}
get :: FilePath -> String -> IO ()
get ca url = do
mstore <- readCertificateStore ca
case mstore of
Just store -> do
manager <- newManager $ managerSettings store
response <- httpLbs (fromString url) manager
putStrLn (show response)
Nothing -> do
putStrLn $ "error: invalid certificate store " ++ ca
main :: IO ()
main = do
args <- getArgs
case args of
ca:url:[] -> get ca url
_ -> do
name <- getProgName
putStrLn $ "usage: " ++ name ++ " ca url"
A couple notes:
The TLS.sharedCAStore settings is where the magic happens. If you want to add your CA to the system store (vs. using only your CA) you can load the system store using getSystemCertificateStore from System.X509, then use Data.X509.CertificateStore to convert back and forth between CertificateStore and [SignedCertificate] to create a store with the system certificates along with your own.
TLS.defaultParamsClient takes a hostname and server id, used for TLS server name indication (SNI), a TLS extension that allows a server to host multiple sites on a single IP (similar to how HTTP/1.1 host headers work). We don't necessarily know what to set this to when we're creating a manager. Fortunately, Network.Connection (used by http-client-tls) appears to override whatever settings we use, so it doesn't matter.
The default for TLS.supportedCiphers is an empty list, so this setting is required (unless you turn off validation or something). Network.Connection defaults to ciphersuite_all but that includes some "not recommended last resource cipher suites" so I opted to use ciphersuite_default instead.
I think you're looking for ClientHooks. You can create a TLSSettings value with that by using the TLSSettings constructor, and then create a ManagerSettings using mkManagerSettings.
I use WinGHCi and my Code(really simple) follows:
module Main
where
import IO
main = do
hSetBuffering stdin LineBuffering
putStrLn "Enter your name: "
name <- getLine
putStrLn("Hello, " ++ name ++ ", how are you?");
error message:
2.hs:4:8:
Could not find module `IO'
It is a member of the hidden package `haskell98-2.0.0.1'.
Use -v to see a list of the files searched for.
Failed, modules loaded: none.
(That codes run correctly in WinHugs, but I just want to compile it)
Maybe the question is really trivial, but I'm study Haskell by myself and nobody can be consulted. I try to search in Google, unfortunately can't find anything meaningful.
I get stuck...Thanks in advance.
You want to import System.IO.