http-conduit-1.2.1: HTTP client package with conduit interface and HTTPS support.




This module contains everything you need to initiate HTTP connections. If you want a simple interface based on URLs, you can use simpleHttp. If you want raw power, http is the underlying workhorse of this package. Some examples:

 -- Just download an HTML document and print it.
 import Network.HTTP.Conduit
 import qualified Data.ByteString.Lazy as L

 main = simpleHttp "" >>= L.putStr

This example uses interleaved IO to write the response body to a file in constant memory space.

 import Data.Conduit.Binary (sinkFile)
 import Network.HTTP.Conduit
 import qualified Data.Conduit as C

 main :: IO ()
 main = do
      request <- parseUrl ""
      withManager $ \manager -> do
          Response _ _ bsrc <- http request manager
          bsrc C.$$ sinkFile "google.html"

The following headers are automatically set by this module, and should not be added to requestHeaders:

  • Content-Length
  • Host
  • Accept-Encoding (not currently set, but client usage of this variable will cause breakage).

Any network code on Windows requires some initialization, and the network library provides withSocketsDo to perform it. Therefore, proper usage of this library will always involve calling that function at some point. The best approach is to simply call them at the beginning of your main function, such as:

 import Network.HTTP.Conduit
 import qualified Data.ByteString.Lazy as L
 import Network (withSocketsDo)

 main = withSocketsDo
      $ simpleHttp "" >>= L.putStr


Perform a request

simpleHttp :: MonadIO m => String -> m ByteStringSource

Download the specified URL, following any redirects, and return the response body.

This function will throwIO an HttpException for any response with a non-2xx status code (besides 3xx redirects up to a limit of 10 redirects). It uses parseUrl to parse the input. This function essentially wraps httpLbsRedirect.

Note: Even though this function returns a lazy bytestring, it does not utilize lazy I/O, and therefore the entire response body will live in memory. If you want constant memory usage, you'll need to use the conduit package and http or httpRedirect directly.

httpLbs :: ResourceIO m => Request m -> Manager -> ResourceT m (Response ByteString)Source

Download the specified Request, returning the results as a Response.

This is a simplified version of http for the common case where you simply want the response data as a simple datatype. If you want more power, such as interleaved actions on the response body during download, you'll need to use http directly. This function is defined as:

httpLbs = lbsResponse . http

Even though the Response contains a lazy bytestring, this function does not utilize lazy I/O, and therefore the entire response body will live in memory. If you want constant memory usage, you'll need to use conduit packages's Source returned by http.

Note: Unlike previous versions, this function will perform redirects, as specified by the redirectCount setting.

http :: ResourceIO m => Request m -> Manager -> ResourceT m (Response (Source m ByteString))Source

The most low-level function for initiating an HTTP request.

The first argument to this function gives a full specification on the request: the host to connect to, whether to use SSL, headers, etc. Please see Request for full details. The second argument specifies which Manager should be used.

This function then returns a Response with a Source. The Response contains the status code and headers that were sent back to us, and the Source contains the body of the request. Note that this Source allows you to have fully interleaved IO actions during your HTTP download, making it possible to download very large responses in constant memory. You may also directly connect the returned Source into a Sink, perhaps a file or another socket.

Note: Unlike previous versions, this function will perform redirects, as specified by the redirectCount setting.


data Proxy Source

Define a HTTP proxy, consisting of a hostname and port number.




proxyHost :: Ascii

The host name of the HTTP proxy.

proxyPort :: Int

The port number of the HTTP proxy.

data RequestBody m Source

When using one of the RequestBodySource / RequestBodySourceChunked constructors, you must ensure that the Source can be called multiple times. Usually this is not a problem.

The RequestBodySourceChunked will send a chunked request body, note that not all servers support this. Only use RequestBodySourceChunked if you know the server you're sending to supports chunked request bodies.

data Response body Source

A simple representation of the HTTP response created by lbsConsumer.


Functor Response

Since 1.1.2.

Typeable1 Response 
Eq body => Eq (Response body) 
Show body => Show (Response body) 


data Request m Source

All information on how to connect to a host and what should be sent in the HTTP request.

If you simply wish to download from a URL, see parseUrl.

The constructor for this data type is not exposed. Instead, you should use either the def method to retrieve a default instance, or parseUrl to construct from a URL, and then use the records below to make modifications. This approach allows http-conduit to add configuration options without breaking backwards compatibility.


def :: Default a => a

The default value for this type.

method :: Request m -> MethodSource

HTTP request method, eg GET, POST.

secure :: Request m -> BoolSource

Whether to use HTTPS (ie, SSL).

path :: Request m -> AsciiSource

Everything from the host to the query string.

proxy :: Request m -> Maybe ProxySource

Optional HTTP proxy.

socksProxy :: Request m -> Maybe SocksConfSource

Optional SOCKS proxy.

rawBody :: Request m -> BoolSource

If True, a chunked and/or gzipped body will not be decoded. Use with caution.

decompress :: Request m -> ContentType -> BoolSource

Predicate to specify whether gzipped data should be decompressed on the fly (see alwaysDecompress and browserDecompress). Default: browserDecompress.

redirectCount :: Request m -> IntSource

How many redirects to follow when getting a resource. 0 means follow no redirects. Default value: 10.

checkStatus :: Request m -> Status -> ResponseHeaders -> Maybe SomeExceptionSource

Check the status code. Note that this will run after all redirects are performed. Default: return a StatusCodeException on non-2XX responses.


data Manager Source

Keeps track of open connections for keep-alive. May be used concurrently by multiple threads.

newManager :: ManagerSettings -> IO ManagerSource

Create a Manager. You must manually call closeManager to shut it down.

closeManager :: Manager -> IO ()Source

Close all connections in a Manager. Afterwards, the Manager can be reused if desired.

withManager :: ResourceIO m => (Manager -> ResourceT m a) -> m aSource

Create a new manager, use it in the provided function, and then release it.

This function uses the default manager settings. For more control, use newManager.


data ManagerSettings Source

Settings for a Manager. Please use the def function and then modify individual settings.

managerConnCount :: ManagerSettings -> IntSource

Number of connections to a single host to keep alive. Default: 10.

managerCheckCerts :: ManagerSettings -> Ascii -> [X509] -> IO TLSCertificateUsageSource

Check if the server certificate is valid. Only relevant for HTTPS.


defaultCheckCerts :: Ascii -> [X509] -> IO TLSCertificateUsageSource

Check certificates using the operating system's certificate checker.

Utility functions

parseUrl :: Failure HttpException m => String -> m (Request m')Source

Convert a URL into a Request.

This defaults some of the values in Request, such as setting method to GET and requestHeaders to [].

Since this function uses Failure, the return monad can be anything that is an instance of Failure, such as IO or Maybe.

applyBasicAuth :: ByteString -> ByteString -> Request m -> Request mSource

Add a Basic Auth header (with the specified user name and password) to the given Request. Ignore error handling:

applyBasicAuth user pass $ fromJust $ parseUrl url

addProxy :: ByteString -> Int -> Request m -> Request mSource

Add a proxy to the the Request so that the Request when executed will use the provided proxy.

lbsResponse :: Resource m => ResourceT m (Response (Source m ByteString)) -> ResourceT m (Response ByteString)Source

Convert a Response that has a Source body to one with a lazy ByteString body.

getRedirectedRequest :: Request m -> ResponseHeaders -> Int -> Maybe (Request m)Source

If a request is a redirection (status code 3xx) this function will create a new request from the old request, the server headers returned with the redirection, and the redirection code itself. This function returns Nothing if the code is not a 3xx, there is no location header included, or if the redirected response couldn't be parsed with parseUrl.

If a user of this library wants to know the url chain that results from a specific request, that user has to re-implement the redirect-following logic themselves. An example of that might look like this:

 myHttp req man = E.catch (C.runResourceT $ http req' man >> return [req'])
                    (\ (StatusCodeException status headers) -> do
                        l <- myHttp (fromJust $ nextRequest status headers) man
                        return $ req' : l)
     where req' = req { redirectCount = 0 }
           nextRequest status headers = getRedirectedRequest req' headers $ W.statusCode status

Decompression predicates

alwaysDecompress :: ContentType -> BoolSource

Always decompress a compressed stream.

browserDecompress :: ContentType -> BoolSource

Decompress a compressed stream unless the content-type is 'application/x-tar'.

Request bodies

urlEncodedBody :: Monad m => [(ByteString, ByteString)] -> Request m' -> Request mSource

Add url-encoded paramters to the Request.

This sets a new requestBody, adds a content-type request header and changes the method to POST.