tests for &select= feature and support for casting columns (usefull when extracting subfields from json columns)

src/PostgREST/PgQuery.hs

@@ -141,9 +141,13 @@ select table params =
    cols = filter ((>0) . T.length) $ map T.strip $ T.split (==',') $ cs columnsParam
 
 selectTerm :: QualifiedIdentifier -> T.Text -> PStmt
-selectTerm table col = B.Stmt (pgFmtJsonbPath table (cs col) <> asT jsonbPath) empty True
+selectTerm table col =
+    case T.splitOn "::" col of
+        [colName,castTo] -> B.Stmt ("CAST (" <> pgFmtJsonbPath table (cs colName) <> " AS " <> castTo <> " )" <> asT (jsonbPath colName)) empty True
+        _-> B.Stmt (pgFmtJsonbPath table (cs col) <> asT (jsonbPath col)) empty True
     where
-        jsonbPath = parseJsonbPath $ cs col
+        jsonbPath :: T.Text -> Maybe JsonbPath
+        jsonbPath c = parseJsonbPath $ cs c
         asT (Just (DoubleArrow _ (KeyIdentifier key))) = " AS " <> pgFmtIdent key
         asT _ = ""
 

test/Feature/QuerySpec.hs

@@ -11,13 +11,14 @@ import SpecHelper
 spec :: Spec
 spec =
   beforeAll (clearTable "items" >> createItems 15)
+   . beforeAll (clearTable "complex_items" >> createComplexItems)
    . beforeAll (clearTable "nullable_integer" >> createNullInteger)
    . beforeAll (
        clearTable "no_pk" >>
        createNulls 2 >>
        createLikableStrings >>
        createJsonData)
-   . afterAll_ (clearTable "items" >> clearTable "no_pk" >> clearTable "simple_pk")
+   . afterAll_ (clearTable "items" >> clearTable "complex_items" >> clearTable "no_pk" >> clearTable "simple_pk")
    . around withApp $ do
 
   describe "Querying a table with a column called count" $
@@ -129,6 +130,37 @@ spec =
       get "/items?always_true=eq.true" `shouldRespondWith`
         [json| [{"id":1},{"id":2},{"id":3},{"id":4},{"id":5},{"id":6},{"id":7},{"id":8},{"id":9},{"id":10},{"id":11},{"id":12},{"id":13},{"id":14},{"id":15}] |]
 
+  describe "Shaping response with select parameter" $ do
+
+    it "selectStar works in absense of parameter" $
+      get "/complex_items?id=eq.3" `shouldRespondWith`
+        "[{\"id\":3,\"name\":\"Three\",\"settings\":{\"foo\":{\"int\":1,\"bar\":\"baz\"}}}]"
+
+    it "one simple column" $
+      get "/complex_items?select=id" `shouldRespondWith`
+        [json| [{"id":1},{"id":2},{"id":3}] |]
+
+    it "one simple column with casting (text)" $
+      get "/complex_items?select=id::text" `shouldRespondWith`
+        [json| [{"id":"1"},{"id":"2"},{"id":"3"}] |]
+
+    it "json column" $
+      get "/complex_items?id=eq.1&select=settings" `shouldRespondWith`
+        [json| [{"settings":{"foo":{"int":1,"bar":"baz"}}}] |]
+
+    it "json subfield one level with casting (json)" $
+      get "/complex_items?id=eq.1&select=settings->>foo::json" `shouldRespondWith`
+        [json| [{"foo":{"int":1,"bar":"baz"}}] |] -- the value of foo here is of type "text"
+
+    it "json subfield two levels (string)" $
+      get "/complex_items?id=eq.1&select=settings->foo->>bar" `shouldRespondWith`
+        [json| [{"bar":"baz"}] |]
+
+    it "json subfield two levels with casting (int)" $
+      get "/complex_items?id=eq.1&select=settings->foo->>int::integer" `shouldRespondWith`
+        [json| [{"int":1}] |] -- the value in the db is an int, but here we expect a string for now
+
+
   describe "ordering response" $ do
     it "by a column asc" $
       get "/items?id=lte.2&order=id.asc"

test/Feature/StructureSpec.hs

@@ -15,6 +15,7 @@ spec = around withApp $ do
       request methodGet "/" [] ""
         `shouldRespondWith` [json| [
           {"schema":"1","name":"auto_incrementing_pk","insertable":true}
+        , {"schema":"1","name":"complex_items","insertable":true}
         , {"schema":"1","name":"compound_pk","insertable":true}
         , {"schema":"1","name":"has_count_column","insertable":false}
         , {"schema":"1","name":"has_fk","insertable":true}

test/SpecHelper.hs

@@ -13,6 +13,7 @@ import Data.Monoid
 import Data.Text hiding (map)
 import qualified Data.Vector as V
 import Control.Monad (void)
+import Control.Applicative
 
 import Network.HTTP.Types.Header (Header, ByteRange, renderByteRange,
                                   hRange, hAuthorization, hAccept)
@@ -118,6 +119,18 @@ createItems n = do
     txn = mapM_ H.unitEx stmts
     stmts = map [H.stmt|insert into "1".items (id) values (?)|] [1..n]
 
+createComplexItems :: IO ()
+createComplexItems = do
+  pool <- testPool
+  void . liftIO $ H.session pool $ H.tx Nothing txn
+  where
+    txn = mapM_ H.unitEx stmts
+    stmts = getZipList $ [H.stmt|insert into "1".complex_items (id, name, settings) values (?,?,?)|]
+        <$> ZipList ([1..3]::[Int])
+        <*> ZipList (["One", "Two", "Three"]::[Text])
+        <*> ZipList ([jobj,jobj,jobj])
+    jobj = (J.object [("foo", J.object [("int", J.Number 1),("bar", J.String "baz")])])
+
 createNulls :: Int -> IO ()
 createNulls n = do
   pool <- testPool

test/fixtures/schema.sql

@@ -201,6 +201,15 @@ CREATE TABLE items (
 
 ALTER TABLE "1".items OWNER TO postgrest_test;
 
+CREATE TABLE complex_items (
+    id bigint NOT NULL,
+    name text,
+    settings json
+);
+
+
+ALTER TABLE "1".complex_items OWNER TO postgrest_test;
+
 
 CREATE SEQUENCE items_id_seq
     START WITH 1
@@ -437,6 +446,8 @@ ALTER TABLE ONLY has_fk
 ALTER TABLE ONLY items
     ADD CONSTRAINT items_pkey PRIMARY KEY (id);
 
+ALTER TABLE ONLY complex_items
+    ADD CONSTRAINT complex_items_pkey PRIMARY KEY (id);
 
 
 ALTER TABLE ONLY menagerie
@@ -539,6 +550,11 @@ REVOKE ALL ON TABLE items FROM postgrest_test;
 GRANT ALL ON TABLE items TO postgrest_test;
 GRANT ALL ON TABLE items TO postgrest_anonymous;
 
+REVOKE ALL ON TABLE complex_items FROM PUBLIC;
+REVOKE ALL ON TABLE complex_items FROM postgrest_test;
+GRANT ALL ON TABLE complex_items TO postgrest_test;
+GRANT ALL ON TABLE complex_items TO postgrest_anonymous;
+
 
 REVOKE ALL ON FUNCTION getitemrange(bigint, bigint) FROM PUBLIC;
 REVOKE ALL ON FUNCTION getitemrange(bigint, bigint) FROM postgrest_test;