From 0940b2dccf06e0ca269c03b6715f1140b80241bf Mon Sep 17 00:00:00 2001
From: Christopher League <league@contrapunctus.net>
Date: Sun, 22 May 2016 14:56:58 -0400
Subject: [PATCH] Simplify serialization of location header

Possible after bug fix in a Hasql that we picked up with the new
dependency bounds in #606. Also includes test to ensure location header
is omitted on bulk insert.
---
 src/PostgREST/App.hs          |  9 +++++----
 src/PostgREST/QueryBuilder.hs | 10 ++++------
 test/Feature/InsertSpec.hs    | 10 ++++++++++
 3 files changed, 19 insertions(+), 10 deletions(-)

diff --git a/src/PostgREST/App.hs b/src/PostgREST/App.hs
index c526389ab..acf65cc54 100644
--- a/src/PostgREST/App.hs
+++ b/src/PostgREST/App.hs
@@ -130,9 +130,10 @@ app dbStructure conf apiRequest =
           let pKeys = map pkName $ filter (filterPk schema table) allPrKeys -- would it be ok to move primary key detection in the query itself?
           let stm = createWriteStatement qi sq mq isSingle (iPreferRepresentation apiRequest) pKeys (contentType == TextCSV) payload
           row <- H.query uniform stm
-          let (_, _, locationFieldsOpt, body) = extractQueryResult row
-              mkHeader fs = [(hLocation, "/" <> cs table <> renderLocationFields fs)]
-              header = maybe [] mkHeader locationFieldsOpt
+          let (_, _, fs, body) = extractQueryResult row
+              header =
+                if null fs then []
+                else [(hLocation, "/" <> cs table <> renderLocationFields fs)]
 
           return $ if iPreferRepresentation apiRequest == Full
             then responseLBS status201 (contentTypeH : header) (cs body)
@@ -391,4 +392,4 @@ instance ToJSON TableOptions where
 
 
 extractQueryResult :: Maybe ResultsWithCount -> ResultsWithCount
-extractQueryResult = fromMaybe (Nothing, 0, Nothing, "")
+extractQueryResult = fromMaybe (Nothing, 0, [], "")
diff --git a/src/PostgREST/QueryBuilder.hs b/src/PostgREST/QueryBuilder.hs
index 5227d9775..10ed4b88d 100644
--- a/src/PostgREST/QueryBuilder.hs
+++ b/src/PostgREST/QueryBuilder.hs
@@ -63,20 +63,18 @@ import           PostgREST.ApiRequest    (PreferRepresentation (..))
 
 {-| The generic query result format used by API responses. The location header
     is represented as a list of strings containing variable bindings like
-    @"k1=eq.42"@. If unused, it's null/Nothing rather than the empty list
-    because 'PostgreSQL.Binary.Decoder.arrayDimension' cannot decode an empty
-    array!
+    @"k1=eq.42"@, or the empty list if there is no location header.
 -}
-type ResultsWithCount = (Maybe Int64, Int64, Maybe [BS.ByteString], BS.ByteString)
+type ResultsWithCount = (Maybe Int64, Int64, [BS.ByteString], BS.ByteString)
 
 standardRow :: HD.Row ResultsWithCount
 standardRow = (,,,) <$> HD.nullableValue HD.int8 <*> HD.value HD.int8
-                    <*> HD.nullableValue header <*> HD.value HD.bytea
+                    <*> HD.value header <*> HD.value HD.bytea
   where
     header = HD.array $ HD.arrayDimension replicateM $ HD.arrayValue HD.bytea
 
 noLocationF :: Text
-noLocationF = "NULL::text[]"
+noLocationF = "array[]::text[]"
 
 {-| Read and Write api requests use a similar response format which includes
     various record counts and possible location header. This is the decoder
diff --git a/test/Feature/InsertSpec.hs b/test/Feature/InsertSpec.hs
index c176c54d4..3be0233d4 100644
--- a/test/Feature/InsertSpec.hs
+++ b/test/Feature/InsertSpec.hs
@@ -138,6 +138,16 @@ spec = do
           JSON.decode (simpleBody r) `shouldBe` Just [expectedObj]
           simpleStatus r `shouldBe` ok200
 
+    context "with bulk insert" $
+      it "returns 201 but no location header" $ do
+        let bulkData = [json| [ {"k1":21, "k2":"hello world"}
+                              , {"k1":22, "k2":"bye for now"}]
+                            |]
+        p <- request methodPost "/compound_pk" [] bulkData
+        liftIO $ do
+          simpleStatus p `shouldBe` created201
+          lookup hLocation (simpleHeaders p) `shouldBe` Nothing
+
     context "with invalid json payload" $
       it "fails with 400 and error" $
         post "/simple_pk" "}{ x = 2" `shouldRespondWith` 400