version 0.1.0

- readFromCSV
- readFromCSVRaw
- writeToCSV
- writeToCSVRaw

README.md

@@ -14,5 +14,5 @@ General Public License for more details.
 You should have received a copy of the GNU General Public License
 along with this program.  If not, see <https://www.gnu.org/licenses/>.
 
-## Important Note
+## Executive Summary
-This library is not yet ready for release.  As such, all code should be considered to be unstable and subject to change at any time.
+This library allows for reading and writing to and from CSV files in a streaming manner.  Files can be read and written to on a row-by-row basis allowing larger files to be worked with, since the whole file doesn't have to be loaded to manipulate it.  It is based on the [conduit](https://hackage.haskell.org/package/conduit] library.

csv-sip.cabal

@@ -5,10 +5,12 @@ cabal-version: 2.2
 -- see: https://github.com/sol/hpack
 
 name:           csv-sip
-version:        0.0.0
+version:        0.1.0
 synopsis:       extracts data from a CSV file
 description:    extracts data from a CSV file - see README.md for more details
 category:       Data
+homepage:       https://codeberg.org/jlamothe/csv-sip
+bug-reports:    https://codeberg.org/jlamothe/csv-sip/issues
 author:         Jonathan Lamothe
 maintainer:     jonathan@jlamothe.net
 copyright:      (C) 2022 Jonathan Lamothe

package.yaml

@@ -1,5 +1,5 @@
 name:                csv-sip
-version:             0.0.0
+version:             0.1.0
 license:             GPL-3.0-or-later
 author:              "Jonathan Lamothe"
 maintainer:          "jonathan@jlamothe.net"
@@ -17,6 +17,8 @@ category:            Data
 # complications of embedding Haddock markup inside cabal files, it is
 # common to point users to the README.md file.
 description:         extracts data from a CSV file - see README.md for more details
+homepage:            https://codeberg.org/jlamothe/csv-sip
+bug-reports:         https://codeberg.org/jlamothe/csv-sip/issues
 
 ghc-options:
 - -Wall

src/Data/CSV/Sip.hs

@@ -26,12 +26,29 @@ along with this program.  If not, see <https://www.gnu.org/licenses/>.
 {-# LANGUAGE LambdaCase, OverloadedStrings #-}
 
 module Data.CSV.Sip (
-  -- * Read an entire CSV file
+  -- * Working with Files
+  -- ** Read an entire CSV file
   slurpCSV,
   slurpRawCSV,
   slurpLabelledCSV,
   slurpRawLabelledCSV,
+  -- ** Write an entire CSV file
+  writeCSV,
+  writeRawCSV,
   -- * Conduits
+  -- ** Producers
+  readFromCSV,
+  readFromCSVRaw,
+  encodeCSV,
+  encodeRawCSV,
+  -- ** Consumers
+  writeToCSV,
+  writeToCSVRaw,
+  -- ** Transformers
+  -- *** Encoding
+  encodeRows,
+  encodeRawRows,
+  -- *** Decoding
   labelFields,
   decodeRows,
   decodeRawRows,
@@ -45,6 +62,7 @@ import Conduit
   , await
   , mapC
   , runConduit
+  , sinkFile
   , sourceFile
   , yield
   , (.|)
@@ -53,11 +71,11 @@ import Control.Monad (unless)
 import Control.Monad.Trans.Class (lift)
 import Control.Monad.Trans.State (StateT, evalStateT, get, gets, modify)
 import qualified Data.ByteString as BS
-import Data.Conduit.List (consume)
+import Data.Conduit.List (consume, sourceList)
 import qualified Data.Map as M
 import Data.Maybe (fromMaybe)
 import qualified Data.Text as T
-import Data.Text.Encoding (decodeUtf8')
+import Data.Text.Encoding (decodeUtf8', encodeUtf8)
 import Data.Word (Word8)
 
 -- | read an entire CSV file
@@ -94,6 +112,90 @@ slurpRawLabelledCSV
 slurpRawLabelledCSV file = runConduit $
   sourceFile file .| decodeRawRows .| labelFields .|consume
 
+-- | write a CSV file from Text-based rows
+writeCSV
+  :: MonadResource m
+  => FilePath
+  -- ^ the path to the file to write to
+  -> [[T.Text]]
+  -- ^ the fields/rows being written
+  -> m ()
+writeCSV file csv = runConduit $ encodeCSV csv .| sinkFile file
+
+-- | write a CSV file from raw ByteString-based rows
+writeRawCSV
+  :: MonadResource m
+  => FilePath
+  -- ^ the path to the file to write to
+  -> [[BS.ByteString]]
+  -- ^ the fields/rows being written
+  -> m ()
+writeRawCSV file csv = runConduit $ encodeRawCSV csv .| sinkFile file
+
+-- | reads a stream of Text-based rows from a CSV file
+readFromCSV
+  :: MonadResource m
+  => FilePath
+  -- ^ the path to the CSV file to read from
+  -> ConduitT i [T.Text] m ()
+readFromCSV file = sourceFile file .| decodeRows
+
+-- | reads a stream of ByteString-based rows from a CSV file
+readFromCSVRaw
+  :: MonadResource m
+  => FilePath
+  -- ^ the path to the CSV file to read from
+  -> ConduitT i [BS.ByteString] m ()
+readFromCSVRaw file = sourceFile file .| decodeRawRows
+
+-- | encode an entire CSV file
+encodeCSV
+  :: Monad m
+  => [[T.Text]]
+  -- ^ the data being encoded, organized into rows and fields
+  -> ConduitT () BS.ByteString m ()
+encodeCSV csv = sourceList csv .| encodeRows
+
+-- | encode an entire CSV file
+encodeRawCSV
+  :: Monad m
+  => [[BS.ByteString]]
+  -- ^ the data being encoded, organized into rows and fields
+  -> ConduitT () BS.ByteString m ()
+encodeRawCSV csv = sourceList csv .| encodeRawRows
+
+-- | Writes a stream of Text-based rows to a CSV file
+writeToCSV
+  :: MonadResource m
+  => FilePath
+  -- ^ the path to the CSV file to write to
+  -> ConduitT [T.Text] o m ()
+writeToCSV file = encodeRows .| sinkFile file
+
+-- | Writes a stream of ByteString-based rows to a CSV file
+writeToCSVRaw
+  :: MonadResource m
+  => FilePath
+  -- ^ the path to the CSV file to write to
+  -> ConduitT [BS.ByteString] o m ()
+writeToCSVRaw file = encodeRawRows .| sinkFile file
+
+-- | encode a CSV stream row by row, each element in the list read
+-- represents a field, with the entire list representing a row
+encodeRows :: Monad m => ConduitT [T.Text] BS.ByteString m ()
+encodeRows = mapC (map encodeUtf8) .| encodeRawRows
+
+-- | encode raw CSV stream row by row, each element in the list read
+-- represents a field, with the entire list representing a row
+encodeRawRows :: Monad m => ConduitT [BS.ByteString] BS.ByteString m ()
+encodeRawRows = await >>= \case
+
+  Just fs-> do
+    encodeFields fs
+    encodeRawRows
+
+  Nothing -> return ()
+
 -- | read a CSV stream, using the first row as a header containing
 -- field labels
 labelFields :: (Monad m, Ord a) => ConduitT [a] (M.Map a a) m ()
@@ -144,6 +246,16 @@ newDecodeState = DecodeState
 
 -- Conduits
 
+encodeFields
+  :: Monad m
+  => [BS.ByteString]
+  -> ConduitT [BS.ByteString] BS.ByteString m ()
+encodeFields []     = yield "\r\n"
+encodeFields [f]    = yield $ escapeField f `BS.append` "\r\n"
+encodeFields (f:fs) = do
+  yield $ escapeField f `BS.append` ","
+  encodeFields fs
+
 labelLoop :: (Monad m, Ord a) => [a] -> ConduitT [a] (M.Map a a) m ()
 labelLoop headers = await >>= \case
   Just values -> do
@@ -270,4 +382,19 @@ dropField s = s
 setQuoted :: Modifier
 setQuoted s = s { isQuoted = True }
 
+-- Helpers
+escapeField :: BS.ByteString -> BS.ByteString
+escapeField field = let
+  bytes = BS.unpack field
+  in BS.concat
+    [ "\""
+    , BS.pack $ escapeLoop bytes
+    , "\""
+    ]
+
+escapeLoop :: [Word8] -> [Word8]
+escapeLoop []        = []
+escapeLoop (0x22:bs) = [0x22, 0x22] ++ escapeLoop bs -- escape quote
+escapeLoop (b:bs)    = b : escapeLoop bs
+
 --jl

test/Data/CSV/SipSpec.hs

@@ -23,6 +23,7 @@ along with this program.  If not, see <https://www.gnu.org/licenses/>.
 module Data.CSV.SipSpec (spec) where
 
 import Conduit (runConduit, (.|))
+import qualified Data.ByteString as BS
 import Data.Char (ord)
 import Data.Conduit.List (consume, sourceList)
 import qualified Data.Map as M
@@ -32,12 +33,88 @@ import Data.CSV.Sip
 
 spec :: Spec
 spec = describe "Data.CSV.Sip" $ do
+  encodeCSVSpec
+  encodeRawCSVSpec
+  encodeRowsSpec
+  encodeRawRowsSpec
   labelFieldsSpec
   decodeRowsSpec
   decodeRawRowsSpec
   decodeUTF8Spec
   toBytesSpec
 
+encodeCSVSpec :: Spec
+encodeCSVSpec = describe "encodeCSV" $ do
+  result <- BS.concat <$> runConduit
+    (encodeCSV input .| consume)
+  it ("shouldBe " ++ show expected) $
+    result `shouldBe` expected
+  where
+
+    input =
+      [ [ "foo",  "a\"b" ]
+      , [ "a\rb", "a\nb" ]
+      ]
+
+    expected = BS.concat
+      [ "\"foo\",\"a\"\"b\"\r\n"
+      , "\"a\rb\",\"a\nb\"\r\n"
+      ]
+
+encodeRawCSVSpec :: Spec
+encodeRawCSVSpec = describe "encodeRawCSV" $ do
+  result <- BS.concat <$> runConduit
+    (encodeRawCSV input .| consume)
+  it ("shouldBe " ++ show expected) $
+    result `shouldBe` expected
+  where
+
+    input =
+      [ [ "foo",  "a\"b" ]
+      , [ "a\rb", "a\nb" ]
+      ]
+
+    expected = BS.concat
+      [ "\"foo\",\"a\"\"b\"\r\n"
+      , "\"a\rb\",\"a\nb\"\r\n"
+      ]
+
+encodeRowsSpec :: Spec
+encodeRowsSpec = describe "encodeRows" $ do
+  result <- BS.concat <$> runConduit
+    (sourceList input .| encodeRows .| consume)
+  it ("shouldBe " ++ show expected) $
+    result `shouldBe` expected
+  where
+
+    input =
+      [ [ "foo",  "a\"b" ]
+      , [ "a\rb", "a\nb" ]
+      ]
+
+    expected = BS.concat
+      [ "\"foo\",\"a\"\"b\"\r\n"
+      , "\"a\rb\",\"a\nb\"\r\n"
+      ]
+
+encodeRawRowsSpec :: Spec
+encodeRawRowsSpec = describe "encodeRawRows" $ do
+  result <- BS.concat <$> runConduit
+    (sourceList input .| encodeRawRows .| consume)
+  it ("should be " ++ show expected) $
+    result `shouldBe` expected
+  where
+
+    input =
+      [ [ "foo",  "a\"b" ]
+      , [ "a\rb", "a\nb" ]
+      ]
+
+    expected = BS.concat
+      [ "\"foo\",\"a\"\"b\"\r\n"
+      , "\"a\rb\",\"a\nb\"\r\n"
+      ]
+
 labelFieldsSpec :: Spec
 labelFieldsSpec = describe "labelFields" $ mapM_
   ( \(label, input, expected) -> context label $ do