Allow returning XML from RPCs

src/PostgREST/Query/SqlFragment.hs

@@ -13,6 +13,7 @@ module PostgREST.Query.SqlFragment
   , asCsvF
   , asJsonF
   , asJsonSingleF
+  , asXmlF
   , countF
   , fromQi
   , limitOffsetF
@@ -176,6 +177,9 @@ asJsonSingleF returnsScalar
   | returnsScalar = "coalesce((json_agg(_postgrest_t.pgrst_scalar)->0)::text, 'null')"
   | otherwise     = "coalesce((json_agg(_postgrest_t)->0)::text, 'null')"
 
+asXmlF :: FieldName -> SqlFragment
+asXmlF fieldName = "coalesce(xmlagg(_postgrest_t." <> pgFmtIdent fieldName <> "), '')"
+
 asBinaryF :: FieldName -> SqlFragment
 asBinaryF fieldName = "coalesce(string_agg(_postgrest_t." <> pgFmtIdent fieldName <> ", ''), '')"
 

src/PostgREST/Query/Statements.hs

@@ -129,9 +129,9 @@ standardRow = (,,,,,) <$> nullableColumn HD.int8 <*> column HD.int8
 type ProcResults = (Maybe Int64, Int64, ByteString, Either Error [GucHeader], Either Error (Maybe Status))
 
 callProcStatement :: Bool -> Bool -> SQL.Snippet -> SQL.Snippet -> SQL.Snippet -> Bool ->
-                     Bool -> Bool -> Bool -> Maybe FieldName -> Bool ->
+                     Bool -> Bool -> Bool -> Bool -> Maybe FieldName -> Bool ->
                      SQL.Statement () ProcResults
-callProcStatement returnsScalar returnsSingle callProcQuery selectQuery countQuery countTotal asSingle asCsv multObjects binaryField =
+callProcStatement returnsScalar returnsSingle callProcQuery selectQuery countQuery countTotal asSingle asCsv asXml multObjects binaryField =
   SQL.dynamicallyParameterized snippet decodeProc
   where
     snippet =
@@ -151,6 +151,7 @@ callProcStatement returnsScalar returnsSingle callProcQuery selectQuery countQue
     bodyF
      | asSingle           = asJsonSingleF returnsScalar
      | asCsv              = asCsvF
+     | isJust binaryField && asXml = asXmlF $ fromJust binaryField
      | isJust binaryField = asBinaryF $ fromJust binaryField
      | returnsSingle
        && not multObjects = asJsonSingleF returnsScalar