From 5a3fbd7111a9fc4d82925add2e3be7aa0eb12d7b Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Franz-Josef=20F=C3=A4rber?= <franzjoseffaerber@gmail.com>
Date: Wed, 4 May 2022 08:25:57 +0200
Subject: [PATCH] Allow returning XML from single-column queries

---
 CHANGELOG.md                         |  1 +
 src/PostgREST/App.hs                 |  1 +
 src/PostgREST/Query/Statements.hs    |  5 +++--
 test/spec/Feature/Query/QuerySpec.hs |  8 ++++++++
 test/spec/fixtures/privileges.sql    |  1 +
 test/spec/fixtures/schema.sql        | 10 ++++++++++
 6 files changed, 24 insertions(+), 2 deletions(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index c31f7871c..227678e5c 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -26,6 +26,7 @@ This project adheres to [Semantic Versioning](http://semver.org/).
  - #2236, Support POSIX regular expression operators for row filtering - @enote-kane
  - #2202, Allow returning XML from RPCs - @fjf2002
  - #2269, Allow `limit=0` in the request query to return an empty array - @gautam1168, @laurenceisla
+ - #2268, Allow returning XML from single-column queries #2268 - @fjf2002
 
 ### Fixed
 
diff --git a/src/PostgREST/App.hs b/src/PostgREST/App.hs
index b284c822f..b5d9f59bd 100644
--- a/src/PostgREST/App.hs
+++ b/src/PostgREST/App.hs
@@ -270,6 +270,7 @@ handleRead headersOnly identifier context@RequestContext{..} = do
         (iAcceptContentType == CTSingularJSON)
         (shouldCount iPreferCount)
         (iAcceptContentType == CTTextCSV)
+        (iAcceptContentType == CTTextXML)
         bField
         configDbPreparedStatements
 
diff --git a/src/PostgREST/Query/Statements.hs b/src/PostgREST/Query/Statements.hs
index 430d7815c..d11255c8a 100644
--- a/src/PostgREST/Query/Statements.hs
+++ b/src/PostgREST/Query/Statements.hs
@@ -86,9 +86,9 @@ createWriteStatement selectQuery mutateQuery wantSingle isInsert asCsv rep pKeys
   decodeStandard =
    fromMaybe (Nothing, 0, [], mempty, Right [], Right Nothing) <$> HD.rowMaybe standardRow
 
-createReadStatement :: SQL.Snippet -> SQL.Snippet -> Bool -> Bool -> Bool -> Maybe FieldName -> Bool ->
+createReadStatement :: SQL.Snippet -> SQL.Snippet -> Bool -> Bool -> Bool ->  Bool -> Maybe FieldName -> Bool ->
                        SQL.Statement () ResultsWithCount
-createReadStatement selectQuery countQuery isSingle countTotal asCsv binaryField =
+createReadStatement selectQuery countQuery isSingle countTotal asCsv asXml binaryField =
   SQL.dynamicallyParameterized snippet decodeStandard
  where
   snippet =
@@ -109,6 +109,7 @@ createReadStatement selectQuery countQuery isSingle countTotal asCsv binaryField
   bodyF
     | asCsv = asCsvF
     | isSingle = asJsonSingleF False
+    | isJust binaryField && asXml = asXmlF $ fromJust binaryField
     | isJust binaryField = asBinaryF $ fromJust binaryField
     | otherwise = asJsonF False
 
diff --git a/test/spec/Feature/Query/QuerySpec.hs b/test/spec/Feature/Query/QuerySpec.hs
index 718806a22..c3ecf3361 100644
--- a/test/spec/Feature/Query/QuerySpec.hs
+++ b/test/spec/Feature/Query/QuerySpec.hs
@@ -1010,6 +1010,14 @@ spec actualPgVersion = do
         , matchHeaders = ["Content-Type" <:> "text/plain; charset=utf-8"]
         }
 
+    it "can get raw xml output with Accept: text/xml" $
+      request methodGet "/xmltest?select=xml" (acceptHdrs "text/xml") ""
+        `shouldRespondWith`
+        "<myxml>foo</myxml>bar<foobar><baz/></foobar>"
+        { matchStatus = 200
+        , matchHeaders = ["Content-Type" <:> "text/xml; charset=utf-8"]
+        }
+
     it "fails if a single column is not selected" $ do
       request methodGet "/images?select=img,name&name=eq.A.png" (acceptHdrs "application/octet-stream") ""
         `shouldRespondWith`
diff --git a/test/spec/fixtures/privileges.sql b/test/spec/fixtures/privileges.sql
index e25b35dcc..7ac0f7d5c 100644
--- a/test/spec/fixtures/privileges.sql
+++ b/test/spec/fixtures/privileges.sql
@@ -178,6 +178,7 @@ GRANT ALL ON TABLE
     , limited_delete_items_wnonuniq_view
     , limited_delete_items_cpk_view
     , limited_update_items_cpk_view
+    , xmltest
 TO postgrest_test_anonymous;
 
 GRANT INSERT ON TABLE insertonly TO postgrest_test_anonymous;
diff --git a/test/spec/fixtures/schema.sql b/test/spec/fixtures/schema.sql
index 7db770c3c..25013243a 100644
--- a/test/spec/fixtures/schema.sql
+++ b/test/spec/fixtures/schema.sql
@@ -2583,3 +2583,13 @@ select $$
   </body>
 </html>$$::pg_catalog.xml;
 $_$;
+
+CREATE TABLE test.xmltest (
+    id integer primary key,
+    xml pg_catalog.xml NOT NULL
+);
+
+INSERT INTO test.xmltest VALUES
+(1, '<myxml>foo</myxml>'),
+(2, 'bar'),
+(3, '<foobar><baz/></foobar>');