Allow alias and hint for columns in query string

src/PostgREST/ApiRequest.hs

@@ -46,6 +46,7 @@ import Web.Cookie                (parseCookies)
 
 import PostgREST.ApiRequest.QueryParams  (QueryParams (..))
 import PostgREST.ApiRequest.Types        (ApiRequestError (..),
+                                          ColumnItem (..),
                                           RangeError (..))
 import PostgREST.Config                  (AppConfig (..),
                                           OpenAPIMode (..))
@@ -55,8 +56,7 @@ import PostgREST.RangeQuery              (NonnegRange, allRange,
                                           hasLimitZero,
                                           rangeRequested)
 import PostgREST.SchemaCache             (SchemaCache (..))
-import PostgREST.SchemaCache.Identifiers (FieldName,
-                                          QualifiedIdentifier (..),
+import PostgREST.SchemaCache.Identifiers (QualifiedIdentifier (..),
                                           Schema)
 
 import qualified PostgREST.ApiRequest.Preferences as Preferences
@@ -117,7 +117,7 @@ data ApiRequest = ApiRequest {
   , iPayload             :: Maybe Payload                    -- ^ Data sent by client and used for mutation actions
   , iPreferences         :: Preferences.Preferences          -- ^ Prefer header values
   , iQueryParams         :: QueryParams.QueryParams
-  , iColumns             :: S.Set (Tree FieldName)           -- ^ parsed colums from &columns parameter and payload
+  , iColumns             :: S.Set (Tree ColumnItem)          -- ^ parsed colums from &columns parameter and payload
   , iHeaders             :: [(ByteString, ByteString)]       -- ^ HTTP request headers
   , iCookies             :: [(ByteString, ByteString)]       -- ^ Request Cookies
   , iPath                :: ByteString                       -- ^ Raw request path
@@ -237,12 +237,12 @@ getRanges method QueryParams{qsOrder,qsRanges} hdrs
     isInvalidRange = topLevelRange == emptyRange && not (hasLimitZero limitRange)
     topLevelRange = fromMaybe allRange $ HM.lookup "limit" ranges -- if no limit is specified, get all the request rows
 
-getPayload :: RequestBody -> MediaType -> QueryParams.QueryParams -> Action -> Either ApiRequestError (Maybe Payload, S.Set (Tree FieldName))
+getPayload :: RequestBody -> MediaType -> QueryParams.QueryParams -> Action -> Either ApiRequestError (Maybe Payload, S.Set (Tree ColumnItem))
 getPayload reqBody contentMediaType QueryParams{qsColumns} action = do
   checkedPayload <- if shouldParsePayload then payload else Right Nothing
   let cols = case (checkedPayload, columns) of
-        (Just ProcessedJSON{payKeys}, _)       -> S.map (`Node` []) payKeys
-        (Just ProcessedUrlEncoded{payKeys}, _) -> S.map (`Node` []) payKeys
+        (Just ProcessedJSON{payKeys}, _)       -> S.map ((`Node` []) . ColumnField) payKeys
+        (Just ProcessedUrlEncoded{payKeys}, _) -> S.map ((`Node` []) . ColumnField) payKeys
         (Just RawJSON{}, Just cls)             -> S.fromList cls
         _                                      -> S.empty
   return (checkedPayload, cols)

src/PostgREST/ApiRequest/QueryParams.hs

@@ -44,10 +44,10 @@ import PostgREST.RangeQuery              (NonnegRange, allRange,
 import PostgREST.SchemaCache.Identifiers (FieldName)
 
 import PostgREST.ApiRequest.Types (AggregateFunction (..),
-                                   EmbedParam (..), EmbedPath, Field,
-                                   Filter (..), FtsOperator (..),
-                                   Hint, JoinType (..),
-                                   JsonOperand (..),
+                                   ColumnItem (..), EmbedParam (..),
+                                   EmbedPath, Field, Filter (..),
+                                   FtsOperator (..), Hint,
+                                   JoinType (..), JsonOperand (..),
                                    JsonOperation (..), JsonPath,
                                    ListVal, LogicOperator (..),
                                    LogicTree (..), OpExpr (..),
@@ -73,7 +73,7 @@ data QueryParams =
     -- ^ &order parameters for each level
     , qsLogic          :: [(EmbedPath, LogicTree)]
     -- ^ &and and &or parameters used for complex boolean logic
-    , qsColumns        :: Maybe [Tree FieldName]
+    , qsColumns        :: Maybe [Tree ColumnItem]
     -- ^ &columns parameter and payload
     , qsSelect         :: [Tree SelectItem]
     -- ^ &select parameter used to shape the response
@@ -261,8 +261,8 @@ pRequestLogicTree (k, v) = mapError $ (,) <$> embedPath <*> logicTree
       P.parse pLogicTree ("failed to parse logic tree (" ++ toS v ++ ")") $ toS (op <> v)
 
 
--- Satisfies the form: /products?columns=name,suppliers(name)
-pRequestColumns :: Maybe Text -> Either QPError (Maybe [Tree FieldName])
+-- Satisfies the form: /products?columns=name,sup:suppliers!fk(name)
+pRequestColumns :: Maybe Text -> Either QPError (Maybe [Tree ColumnItem])
 pRequestColumns colStr =
   case colStr of
     Just str ->
@@ -479,11 +479,13 @@ pRelationSelect = lexeme $ do
     try (void $ lookAhead (string "("))
     return $ SelectRelation name alias hint jType
 
-pRelationColumn :: Parser FieldName
+pRelationColumn :: Parser ColumnItem
 pRelationColumn = lexeme $ do
+  alias <- optionMaybe ( try(pFieldName <* aliasSeparator) )
   name <- pFieldName
+  (hint, _) <- pEmbedParams
   try (void $ lookAhead (string "("))
-  return name
+  return $ ColumnRelation name alias hint
 
 -- |
 -- Parse regular fields in select
@@ -852,17 +854,17 @@ pLogicPath = do
 pColumns :: Parser [FieldName]
 pColumns = pFieldName `sepBy1` lexeme (char ',')
 
-pColumnForest :: Parser [Tree FieldName]
+pColumnForest :: Parser [Tree ColumnItem]
 pColumnForest = pColumnTree `sepBy1` lexeme (char ',')
   where
     pColumnTree =  Node <$> try pRelationColumn <*> between (char '(') (char ')') pColumnForest <|>
                    Node <$> pColumnName <*> pure []
 
-pColumnName :: Parser FieldName
+pColumnName :: Parser ColumnItem
 pColumnName = lexeme $ do
   fld <- pFieldName
   pEnd
-  return fld
+  return $ ColumnField fld
   where
     pEnd = try (void $ lookAhead (string ")")) <|>
            try (void $ lookAhead (string ",")) <|>

src/PostgREST/ApiRequest/Types.hs

@@ -33,6 +33,7 @@ module PostgREST.ApiRequest.Types
   , QuantOperator(..)
   , FtsOperator(..)
   , SelectItem(..)
+  , ColumnItem(..)
   ) where
 
 import PostgREST.MediaType                (MediaType (..))
@@ -68,6 +69,15 @@ data SelectItem
     }
   deriving (Eq, Show)
 
+data ColumnItem
+  = ColumnField FieldName
+  | ColumnRelation
+    { colRelation :: FieldName
+    , colAlias    :: Maybe Alias
+    , colHint     :: Maybe Hint
+    }
+  deriving (Eq, Show, Ord)
+
 data ApiRequestError
   = AggregatesNotAllowed
   | AmbiguousRelBetween Text Text [Relationship]

src/PostgREST/Plan.hs

@@ -170,7 +170,7 @@ callReadPlan :: QualifiedIdentifier -> AppConfig -> SchemaCache -> ApiRequest ->
 callReadPlan identifier conf sCache apiRequest@ApiRequest{iPreferences=Preferences{..},..} invMethod = do
   let paramKeys = case invMethod of
         InvRead _ -> S.fromList $ fst <$> qsParams'
-        Inv       -> S.map rootLabel iColumns
+        Inv       -> S.map (getColumnAsText . rootLabel) iColumns
   proc@Function{..} <- mapLeft ApiRequestError $
     findProc identifier paramKeys (preferParameters == Just SingleObject) (dbRoutines sCache) iContentMediaType (invMethod == Inv)
   let relIdentifier = QualifiedIdentifier pdSchema (fromMaybe pdName $ Routine.funcTableName proc) -- done so a set returning function can embed other relations
@@ -942,7 +942,7 @@ mutatePlan mutation qi ApiRequest{iPreferences=Preferences{..}, ..} SchemaCache{
     combinedLogic = foldr (addFilterToLogicForest . resolveFilter ctx) logic qsFiltersRoot
     body = payRaw <$> iPayload -- the body is assumed to be json at this stage(ApiRequest validates)
     applyDefaults = preferMissing == Just ApplyDefaults
-    typedColumnsOrError = resolveOrError ctx tbl `traverse` S.toList (S.map rootLabel iColumns)
+    typedColumnsOrError = resolveOrError ctx tbl `traverse` S.toList (S.map (getColumnAsText . rootLabel) iColumns)
 
 resolveOrError :: ResolverContext -> Maybe Table -> FieldName -> Either ApiRequestError CoercibleField
 resolveOrError _ Nothing _ = Left NotFound
@@ -1051,3 +1051,9 @@ negotiateContent conf ApiRequest{iAction=act, iPreferences=Preferences{preferRep
     when' :: Bool -> Maybe a -> Maybe a
     when' True (Just a) = Just a
     when' _ _           = Nothing
+
+getColumnAsText :: ColumnItem -> Text
+getColumnAsText colItem =
+  case colItem of
+    ColumnField col             -> col
+    ColumnRelation{colRelation} -> colRelation