Data.Conduit.Binary

Functions for interacting with bytes.

For many purposes, it's recommended to use the conduit-combinators library, which provides a more complete set of functions.

Files and Handles

Note that most of these functions live in the MonadResource monad to ensure resource finalization even in the presence of exceptions. In order to run such code, you will need to use runResourceT.

Sources

sourceFile :: MonadResource m => FilePath -> Producer m ByteString

Stream the contents of a file as binary data.

Since 0.3.0

sourceHandle :: MonadIO m => Handle -> Producer m ByteString

Stream the contents of a Handle as binary data. Note that this function will not automatically close the Handle when processing completes, since it did not acquire the Handle in the first place.

Since 0.3.0

sourceHandleUnsafe :: MonadIO m => Handle -> Source m ByteString

Same as sourceHandle, but instead of allocating a new buffer for each incoming chunk of data, reuses the same buffer. Therefore, the ByteStrings yielded by this function are not referentially transparent between two different yields.

This function will be slightly more efficient than sourceHandle by avoiding allocations and reducing garbage collections, but should only be used if you can guarantee that you do not reuse a ByteString (or any slice thereof) between two calls to await.

Since 1.0.12

sourceIOHandle :: MonadResource m => IO Handle -> Producer m ByteString

An alternative to sourceHandle. Instead of taking a pre-opened Handle, it takes an action that opens a Handle (in read mode), so that it can open it only when needed and closed it as soon as possible.

Since 0.3.0

sourceFileRange

Arguments

:: MonadResource m

=> FilePath

-> Maybe Integer

Offset

-> Maybe Integer

Maximum count

-> Producer m ByteString

Stream the contents of a file as binary data, starting from a certain offset and only consuming up to a certain number of bytes.

Since 0.3.0

sourceHandleRange

Arguments

:: MonadIO m

=> Handle

-> Maybe Integer

Offset

-> Maybe Integer

Maximum count

-> Producer m ByteString

Stream the contents of a handle as binary data, starting from a certain offset and only consuming up to a certain number of bytes.

Since 1.0.8

sourceHandleRangeWithBuffer

Arguments

:: MonadIO m

=> Handle

-> Maybe Integer

Offset

-> Maybe Integer

Maximum count

-> Int

Buffer size

-> Producer m ByteString

Stream the contents of a handle as binary data, starting from a certain offset and only consuming up to a certain number of bytes. This function consumes chunks as specified by the buffer size.

Since 1.1.8

Sinks

sinkFile :: MonadResource m => FilePath -> Consumer ByteString m ()

Stream all incoming data to the given file.

Since 0.3.0

sinkHandle :: MonadIO m => Handle -> Consumer ByteString m ()

Stream all incoming data to the given Handle. Note that this function will not automatically close the Handle when processing completes.

Since 0.3.0

sinkIOHandle :: MonadResource m => IO Handle -> Consumer ByteString m ()

An alternative to sinkHandle. Instead of taking a pre-opened Handle, it takes an action that opens a Handle (in write mode), so that it can open it only when needed and close it as soon as possible.

Since 0.3.0

Conduits

conduitFile :: MonadResource m => FilePath -> Conduit ByteString m ByteString

Stream the contents of the input to a file, and also send it along the pipeline. Similar in concept to the Unix command tee.

Since 0.3.0

conduitHandle :: MonadIO m => Handle -> Conduit ByteString m ByteString

Stream the contents of the input to a Handle, and also send it along the pipeline. Similar in concept to the Unix command tee. Like sourceHandle, does not close the handle on completion. Related to: conduitFile.

Since 1.0.9

Utilities

Sources

sourceLbs :: Monad m => ByteString -> Producer m ByteString

Stream the chunks from a lazy bytestring.

Since 0.5.0

Sinks

head :: Monad m => Consumer ByteString m (Maybe Word8)

Return the next byte from the stream, if available.

Since 0.3.0

dropWhile :: Monad m => (Word8 -> Bool) -> Consumer ByteString m ()

Ignore all bytes while the predicate returns True.

Since 0.3.0

take :: Monad m => Int -> Consumer ByteString m ByteString

Take the given number of bytes, if available.

Since 0.3.0

drop :: Monad m => Int -> Consumer ByteString m ()

Drop up to the given number of bytes.

Since 0.5.0

sinkCacheLength :: (MonadResource m1, MonadResource m2) => Sink ByteString m1 (Word64, Source m2 ByteString)

Stream the input data into a temp file and count the number of bytes present. When complete, return a new Source reading from the temp file together with the length of the input in bytes.

All resources will be cleaned up automatically.

Since 1.0.5

sinkLbs :: Monad m => Sink ByteString m ByteString

Consume a stream of input into a lazy bytestring. Note that no lazy I/O is performed, but rather all content is read into memory strictly.

Since 1.0.5

mapM_ :: Monad m => (Word8 -> m ()) -> Consumer ByteString m ()

Perform a computation on each Word8 in a stream.

Since 1.0.10

Conduits

isolate :: Monad m => Int -> Conduit ByteString m ByteString

Ensure that only up to the given number of bytes are consume by the inner sink. Note that this does not ensure that all of those bytes are in fact consumed.

Since 0.3.0

takeWhile :: Monad m => (Word8 -> Bool) -> Conduit ByteString m ByteString

Return all bytes while the predicate returns True.

Since 0.3.0

lines :: Monad m => Conduit ByteString m ByteString

Split the input bytes into lines. In other words, split on the LF byte (10), and strip it from the output.

Since 0.3.0