diff --git a/LICENSE b/LICENSE
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--- /dev/null
+++ b/LICENSE
@@ -0,0 +1,30 @@
+Copyright (c) 2019, Obsidian Systems LLC
+
+All rights reserved.
+
+Redistribution and use in source and binary forms, with or without
+modification, are permitted provided that the following conditions are met:
+
+    * Redistributions of source code must retain the above copyright
+      notice, this list of conditions and the following disclaimer.
+
+    * Redistributions in binary form must reproduce the above
+      copyright notice, this list of conditions and the following
+      disclaimer in the documentation and/or other materials provided
+      with the distribution.
+
+    * Neither the name of Obsidian Systems LLC nor the names of other
+      contributors may be used to endorse or promote products derived
+      from this software without specific prior written permission.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
diff --git a/README.md b/README.md
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+++ b/README.md
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+# posgresql-lo-stream
+
+This library provides some convenience functions for working with [Large Objects](https://www.postgresql.org/docs/current/largeobjects.html) in PostgreSQL. This is built on top of [postgresql-simple](https://hackage.haskell.org/package/postgresql-simple/docs/Database-PostgreSQL-Simple-LargeObjects.html), which provides the lower-level functions for interacting with Large Objects.
diff --git a/Setup.hs b/Setup.hs
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+++ b/Setup.hs
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+import Distribution.Simple
+main = defaultMain
diff --git a/postgresql-lo-stream.cabal b/postgresql-lo-stream.cabal
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+++ b/postgresql-lo-stream.cabal
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+cabal-version:       >=1.10
+name:                postgresql-lo-stream
+version:             0.1.0.0
+synopsis:            Utilities for streaming PostgreSQL LargeObjects
+description:         Functions for streaming large objects to and from PostgreSQL
+homepage:            https://github.com/obsidiansystems/posgresql-lo-stream
+bug-reports:         https://github.com/obsidiansystems/postgresql-lo-stream/issues
+license:             BSD3
+license-file:        LICENSE
+author:              Obsidian Systems LLC
+maintainer:          maintainer@obsidian.systems
+copyright:           2019 Obsidian Systems LLC
+category:            Database
+build-type:          Simple
+extra-source-files:  README.md
+
+library
+  exposed-modules:     Database.PostgreSQL.LargeObjects.Stream
+  other-extensions:    LambdaCase
+  build-depends:       base >=4.11 && <4.12
+                     , bytestring >=0.10 && <0.11
+                     , io-streams >=1.5.0 && <1.6
+                     , lifted-base >=0.2.2 && <0.2.4
+                     , monad-loops >=0.4 && <0.5
+                     , mtl >=2.2 && <2.3
+                     , postgresql-simple >=0.5 && <0.6
+  hs-source-dirs:      src
+  default-language:    Haskell2010
diff --git a/src/Database/PostgreSQL/LargeObjects/Stream.hs b/src/Database/PostgreSQL/LargeObjects/Stream.hs
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--- /dev/null
+++ b/src/Database/PostgreSQL/LargeObjects/Stream.hs
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+{-# LANGUAGE LambdaCase #-}
+module Database.PostgreSQL.LargeObjects.Stream where
+
+import Control.Exception.Lifted (AssertionFailed (..), bracket, throwIO)
+import Control.Monad.Loops (whileJust_)
+import Control.Monad.State as State
+import qualified Data.ByteString as BS
+import Data.ByteString.Builder (byteString)
+import qualified Data.ByteString.Builder as BS
+import qualified Data.ByteString.Lazy as LBS
+import Data.IORef (modifyIORef, newIORef, readIORef)
+import Data.Semigroup ((<>))
+import Database.PostgreSQL.Simple
+import Database.PostgreSQL.Simple.LargeObjects (LoFd, Oid (..))
+import qualified Database.PostgreSQL.Simple.LargeObjects as Sql
+import System.IO (IOMode (ReadMode, WriteMode))
+import System.IO.Streams (makeOutputStream)
+import qualified System.IO.Streams as Streams
+
+-- | Given a strict ByteString, create a postgres large object and fill it with those contents.
+newLargeObjectBS
+  :: Connection
+  -> BS.ByteString
+  -> IO Oid
+newLargeObjectBS conn contents = do
+  oid <- Sql.loCreat conn
+  n <- withLargeObject conn oid WriteMode $ \lofd -> Sql.loWrite conn lofd contents
+  let l = BS.length contents
+  when (n /= l) . throwIO . AssertionFailed $
+    "newLargeObjectBS: loWrite reported writing " <> show n <> " bytes, expected " <> show l <> "."
+  return oid
+
+-- | Given a lazy ByteString, create a postgres large object and fill it with those contents.
+-- Also returns the total length of the data written.
+newLargeObjectLBS
+  :: Connection
+  -> LBS.ByteString
+  -> IO (Oid, Int)
+newLargeObjectLBS conn = newLargeObjectStream conn <=< Streams.fromLazyByteString
+
+-- | Create a new large object from an input stream, returning its object id and overall size.
+newLargeObjectStream
+  :: Connection
+  -> Streams.InputStream BS.ByteString
+  -> IO (Oid, Int)
+newLargeObjectStream conn s = do
+  oid <- Sql.loCreat conn
+  t <- withLargeObject conn oid WriteMode $ \lofd -> do
+    whileJust_ (Streams.read s) $ \chunk -> do
+      n <- Sql.loWrite conn lofd chunk
+      let l = BS.length chunk
+      when (n /= l) . throwIO . AssertionFailed $
+        "newLargeObjectStream: loWrite reported writing " <> show n <> " bytes, expected " <> show l <> "."
+    Sql.loTell conn lofd
+  return (oid, t)
+
+-- | Act on a large object given by id, opening and closing the file descriptor appropriately.
+withLargeObject
+  :: Connection
+  -> Oid
+  -> IOMode
+  -> (LoFd -> IO a)
+  -> IO a
+withLargeObject conn oid mode f =
+  bracket (Sql.loOpen conn oid mode)
+          (\lofd -> Sql.loClose conn lofd)
+          f
+
+-- | Stream the contents of a database large object to the given output stream. Useful with Snap's 'addToOutput'.
+streamLargeObject
+  :: Connection
+  -> Oid
+  -> Streams.OutputStream BS.Builder
+  -> IO ()
+streamLargeObject conn oid os =
+  withLargeObject conn oid ReadMode $ \lofd ->
+    fix $ \again -> do
+      chunk <- Sql.loRead conn lofd 8192 -- somewhat arbitrary
+      case BS.length chunk of
+        0 -> return ()
+        _ -> do
+          Streams.write (Just $ byteString chunk) os
+          again
+
+-- | Stream the contents of a database large object to the given output stream. Useful with Snap's 'addToOutput'.
+streamLargeObjectRange
+  :: Connection
+  -> Oid
+  -> Int
+  -> Int
+  -> Streams.OutputStream BS.Builder
+  -> IO ()
+streamLargeObjectRange conn oid start end os =
+  withLargeObject conn oid ReadMode $ \lofd -> do
+    _ <- Sql.loSeek conn lofd Sql.AbsoluteSeek start
+    let again n = do
+          let nextChunkSize = min 8192 (end - n)
+          chunk <- Sql.loRead conn lofd nextChunkSize
+          case BS.length chunk of
+            0 -> return ()
+            k -> do
+              Streams.write (Just $ byteString chunk) os
+              again (n + k)
+    again start
+
+-- | Act on the contents of a LargeObject as a Lazy ByteString
+withLargeObjectLBS :: Connection -> Oid -> (LBS.ByteString -> IO ()) -> IO ()
+withLargeObjectLBS conn oid f = do
+  lo <- newIORef mempty
+  cb <- makeOutputStream $ \case
+    Just chunk -> modifyIORef lo $ \chunks -> chunks <> chunk
+    Nothing -> do
+      payload <- readIORef lo
+      f $ BS.toLazyByteString payload
+  streamLargeObject conn oid cb
+  Streams.write Nothing cb