From 4ddd5b4a76e076f8c34f56bdfc82e32ce3da613e Mon Sep 17 00:00:00 2001
From: Laurence Isla <lau.isla.c@gmail.com>
Date: Tue, 27 Dec 2022 16:16:41 -0500
Subject: [PATCH] Add upsert headers for POST requests to the OpenAPI output

---
 CHANGELOG.md                             |  1 +
 src/PostgREST/Response/OpenAPI.hs        | 20 +++++++++++++++-----
 test/spec/Feature/OpenApi/OpenApiSpec.hs |  2 +-
 3 files changed, 17 insertions(+), 6 deletions(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 82feceba2..0789fd8e7 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -26,6 +26,7 @@ This project adheres to [Semantic Versioning](http://semver.org/).
  - #2575, Replace misleading error message when no function is found with a hint containing functions/parameters names suggestions - @laurenceisla
  - #2569, Replace misleading error message when no relationship is found with a hint containing parent/child names suggestions - @laurenceisla
  - #1405, Add the required OpenAPI items object when the parameter is an array - @laurenceisla
+ - #2592, Add upsert headers for POST requests to the OpenAPI output - @laurenceisla
 
 ## [10.1.1] - 2022-11-08
 
diff --git a/src/PostgREST/Response/OpenAPI.hs b/src/PostgREST/Response/OpenAPI.hs
index d159d3bac..240551e54 100644
--- a/src/PostgREST/Response/OpenAPI.hs
+++ b/src/PostgREST/Response/OpenAPI.hs
@@ -161,7 +161,15 @@ makePreferParam ts =
   & schema .~ ParamOther ((mempty :: ParamOtherSchema)
     & in_ .~ ParamHeader
     & type_ ?~ SwaggerString
-    & enum_ .~ JSON.decode (JSON.encode ts))
+    & enum_ .~ JSON.decode (JSON.encode $ foldl (<>) [] (val <$> ts)))
+  where
+    val :: Text -> [Text]
+    val = \case
+      "count"      -> ["count=none"]
+      "params"     -> ["params=single-object"]
+      "return"     -> ["return=representation", "return=minimal", "return=none"]
+      "resolution" -> ["resolution=ignore-duplicates", "resolution=merge-duplicates"]
+      _            -> []
 
 makeProcParam :: ProcDescription -> [Referenced Param]
 makeProcParam pd =
@@ -174,9 +182,11 @@ makeProcParam pd =
 
 makeParamDefs :: [Table] -> [(Text, Param)]
 makeParamDefs ti =
-  [ ("preferParams", makePreferParam ["params=single-object"])
-  , ("preferReturn", makePreferParam ["return=representation", "return=minimal", "return=none"])
-  , ("preferCount", makePreferParam ["count=none"])
+  -- TODO: create Prefer for each method (GET, PATCH, etc.)
+  [ ("preferParams", makePreferParam ["params"])
+  , ("preferReturn", makePreferParam ["return"])
+  , ("preferCount", makePreferParam ["count"])
+  , ("preferPost", makePreferParam ["return", "resolution"])
   , ("select", (mempty :: Param)
       & name        .~ "select"
       & description ?~ "Filtering Columns"
@@ -276,7 +286,7 @@ makePathItem t = ("/" ++ T.unpack tn, p $ tableInsertable t || tableUpdatable t
         )
       )
     postOp = tOp
-      & parameters .~ fmap ref ["body." <> tn, "select", "preferReturn"]
+      & parameters .~ fmap ref ["body." <> tn, "select", "preferPost"]
       & at 201 ?~ "Created"
     patchOp = tOp
       & parameters .~ fmap ref (rs <> ["body." <> tn, "preferReturn"])
diff --git a/test/spec/Feature/OpenApi/OpenApiSpec.hs b/test/spec/Feature/OpenApi/OpenApiSpec.hs
index 31aedfb06..b7603b111 100644
--- a/test/spec/Feature/OpenApi/OpenApiSpec.hs
+++ b/test/spec/Feature/OpenApi/OpenApiSpec.hs
@@ -91,7 +91,7 @@ spec actualPgVersion = describe "OpenAPI" $ do
             [
               { "$ref": "#/parameters/body.child_entities" },
               { "$ref": "#/parameters/select" },
-              { "$ref": "#/parameters/preferReturn" }
+              { "$ref": "#/parameters/preferPost" }
             ]
           |]