Parse headers from an email

addressbook.cabal

@@ -19,6 +19,7 @@ extra-source-files:  CHANGELOG.md
 library
   exposed-modules:     MyLib
                      , Data.Email.Header
+                     , Data.Email
   -- other-modules:
   -- other-extensions:
   default-extensions:  OverloadedStrings
@@ -26,8 +27,10 @@ library
   build-depends:       base ^>=4.13.0.0
                      , attoparsec
                      , mtl
-                     , pipes
+                     , conduit
-                     , pipes-bytestring
+                     , conduit-extra
+                     , bytestring
+                     , lens
                      , text
                      , bytestring-trie
                      , vector
@@ -47,6 +50,7 @@ test-suite addressbook-test
   default-extensions:  OverloadedStrings
                        LambdaCase
   other-modules:       Test.Data.Email.Header
+                     , Test.Data.Email
   type:                exitcode-stdio-1.0
   hs-source-dirs:      test
   main-is:             MyLibTest.hs
@@ -57,6 +61,9 @@ test-suite addressbook-test
                      , tasty-hunit
                      , HUnit
                      , hedgehog
+                     , bytestring
                      , hedgehog-corpus
                      , text
                      , vector
+                     , conduit
+                     , conduit-extra

default.nix

@@ -1,6 +1,6 @@
-{ mkDerivation, attoparsec, base, bytestring-trie, hedgehog
+{ mkDerivation, attoparsec, base, bytestring, bytestring-trie
-, hedgehog-corpus, HUnit, mtl, pipes, pipes-bytestring, stdenv
+, conduit, conduit-extra, hedgehog, hedgehog-corpus, HUnit, lens
-, tasty, tasty-hedgehog, tasty-hunit, text, vector
+, mtl, stdenv, tasty, tasty-hedgehog, tasty-hunit, text, vector
 }:
 mkDerivation {
   pname = "addressbook";
@@ -9,13 +9,13 @@ mkDerivation {
   isLibrary = true;
   isExecutable = true;
   libraryHaskellDepends = [
-    attoparsec base bytestring-trie mtl pipes pipes-bytestring text
+    attoparsec base bytestring bytestring-trie conduit conduit-extra
-    vector
+    lens mtl text vector
   ];
   executableHaskellDepends = [ base ];
   testHaskellDepends = [
-    base hedgehog hedgehog-corpus HUnit tasty tasty-hedgehog
+    base bytestring conduit conduit-extra hedgehog hedgehog-corpus
-    tasty-hunit text vector
+    HUnit tasty tasty-hedgehog tasty-hunit text vector
   ];
   license = stdenv.lib.licenses.bsd3;
 }

src/Data/Email.hs

@@ -0,0 +1,13 @@
+module Data.Email where
+
+import Data.Email.Header
+
+import Conduit
+import qualified Data.Conduit.Combinators as C
+import qualified Data.Conduit.Text as CT
+
+import Data.ByteString
+       (ByteString)
+
+parseEmail :: (MonadThrow m, Monad m) => ConduitM ByteString Header m ()
+parseEmail = CT.decode CT.utf8 .| CT.lines .| C.concatMap decode

test/MyLibTest.hs

@@ -2,11 +2,13 @@ module Main (main) where
 
 import Test.Tasty
 
+import qualified Test.Data.Email as Data.Email
 import qualified Test.Data.Email.Header as Data.Email.Header
 
 tests :: TestTree
 tests = testGroup "tests"
   [ Data.Email.Header.tests
+  , Data.Email.tests
   ]
 
 main :: IO ()

test/Test/Data/Email.hs

@@ -0,0 +1,32 @@
+{-# LANGUAGE OverloadedLists #-}
+module Test.Data.Email where
+
+import Test.Tasty
+import Test.Tasty.HUnit
+
+import Data.ByteString.Lazy.Char8 (ByteString)
+
+import qualified Data.Conduit.List as CL
+import qualified Data.Conduit.Binary as CB
+import Conduit
+
+import Data.Email.Header
+import Data.Email
+
+sample :: ByteString
+sample =
+  "Subject: Hello worldddd\n\
+  \From: me@example.com\n\
+  \To: you <you@example.com>\n\
+  \ \n\n \
+  \foo"
+
+parseToList :: ByteString -> IO [Header]
+parseToList _ = runConduit (CB.sourceLbs sample .| parseEmail .| CL.consume)
+
+tests :: TestTree
+tests = testGroup "Data.Email"
+  [ testCase "Can parse a sample email" $ do
+      got <- parseToList sample
+      got @?= [ From "me@example.com", To ["you@example.com"]]
+  ]