Add support for bulk-delete

CHANGELOG.md

@@ -44,6 +44,7 @@ This project adheres to [Semantic Versioning](http://semver.org/).
    + Limited to generating the plan of a json representation(`application/json`) but can be extended later to allow other representations.
    + The plan can be obtained in text(`Accept: application/vnd.pgrst.plan+text`) and json(`Accept: application/vnd.pgrst.plan+json` or `Accept: application/vnd.pgrst.plan`) format.
  - #2397, Fix race conditions managing database connection helper - @robx
+ - #2314, Allow bulk delete by using DELETE with an array body - @laurenceisla
 
 ### Fixed
 

src/PostgREST/Query/QueryBuilder.hs

@@ -144,13 +144,24 @@ mutateRequestToQuery (Update mainQi uCols body logicForest pkFlts range ordts re
     rangeCols = BS.intercalate ", " ((\col -> pgFmtIdent col <> " = (SELECT " <> pgFmtIdent col <> " FROM pgrst_update_body) ") <$> S.toList uCols)
     (whereRangeIdF, rangeIdF) = mutRangeF mainQi (fst . otTerm <$> ordts)
 
-mutateRequestToQuery (Delete mainQi logicForest range ordts returnings)
+mutateRequestToQuery (Delete mainQi dCols body logicForest range ordts returnings)
+  -- The body is not mandatory
   | range == allRange =
+    let whereLogic | null logicForest && hasEmptyBody = mempty 
+                   | otherwise                        = "WHERE " <> logicForestAndDelBodyF in
+    (if hasEmptyBody
+      then mempty
+      else "WITH " <> normalizedBody body <> " ") <>
     "DELETE FROM " <> SQL.sql (fromQi mainQi) <> " " <>
+    (if hasEmptyBody
+      then mempty
+      else "USING (SELECT * FROM json_populate_recordset (null::" <> SQL.sql (fromQi mainQi) <> " , " <> SQL.sql selectBody <> " )) pgrst_delete_body ") <>
     whereLogic <> " " <>
     SQL.sql (returningF mainQi returnings)
 
+  -- When using limits, the payload is ignored.
   | otherwise =
+    let whereLogic = if null logicForest then mempty else " WHERE " <> logicForestF in
     "WITH " <>
     "pgrst_affected_rows AS (" <>
       "SELECT " <> SQL.sql rangeIdF <> " FROM " <> SQL.sql (fromQi mainQi) <>
@@ -164,7 +175,10 @@ mutateRequestToQuery (Delete mainQi logicForest range ordts returnings)
     SQL.sql (returningF mainQi returnings)
 
   where
-    whereLogic = if null logicForest then mempty else " WHERE " <> intercalateSnippet " AND " (pgFmtLogicTree mainQi <$> logicForest)
+    hasEmptyBody = isNothing body || null dCols
+    logicForestF = intercalateSnippet " AND " (pgFmtLogicTree mainQi <$> logicForest)
+    pgrstDeleteBodyF = SQL.sql (BS.intercalate " AND " $ (\x -> pgFmtColumn mainQi x <> " = " <> pgFmtColumn (QualifiedIdentifier mempty "pgrst_delete_body") x) <$> S.toList dCols)
+    logicForestAndDelBodyF = intercalateSnippet " AND " ([logicForestF | not (null logicForest)] ++ [pgrstDeleteBodyF | not hasEmptyBody])
     (whereRangeIdF, rangeIdF) = mutRangeF mainQi (fst . otTerm <$> ordts)
 
 requestToCallProcQuery :: CallRequest -> SQL.Snippet

src/PostgREST/Request/ApiRequest.hs

@@ -256,6 +256,7 @@ apiRequest conf@AppConfig{..} dbStructure req reqBody queryparams@QueryParams{..
   columns = case action of
     ActionMutate MutationCreate -> qsColumns
     ActionMutate MutationUpdate -> qsColumns
+    ActionMutate MutationDelete -> qsColumns
     ActionInvoke InvPost        -> qsColumns
     _                           -> Nothing
 
@@ -321,6 +322,7 @@ apiRequest conf@AppConfig{..} dbStructure req reqBody queryparams@QueryParams{..
     (ActionInvoke InvPost, _)              -> True
     (ActionMutate MutationSingleUpsert, _) -> True
     (ActionMutate MutationUpdate, _)       -> True
+    (ActionMutate MutationDelete, _)       -> not (LBS.null reqBody)
     _                                      -> False
   relevantPayload = case (contentMediaType, action) of
     -- Though ActionInvoke GET/HEAD doesn't really have a payload, we use the payload variable as a way

src/PostgREST/Request/DbRequestBuilder.hs

@@ -329,7 +329,8 @@ mutateRequest mutation schema tName ApiRequest{..} pkCols readReq = mapLeft ApiR
           then Right $ Insert qi iColumns body (Just (MergeDuplicates, pkCols)) combinedLogic returnings
         else
           Left InvalidFilters
-    MutationDelete -> Right $ Delete qi combinedLogic iTopLevelRange rootOrder returnings
+    MutationDelete -> Right $ Delete qi iColumns body combinedLogic iTopLevelRange rootOrder returnings
+
   where
     confCols = fromMaybe pkCols qsOnConflict
     QueryParams.QueryParams{..} = iQueryParams

src/PostgREST/Request/MutateQuery.hs

@@ -38,6 +38,8 @@ data MutateQuery
       }
   | Delete
       { in_       :: QualifiedIdentifier
+      , delCols   :: S.Set FieldName
+      , delBody   :: Maybe LBS.ByteString
       , where_    :: [LogicTree]
       , mutRange  :: NonnegRange
       , mutOrder  :: [OrderTerm]