First stab at __type field

andreas · Jul 24, 2019 · 9743915 · 9743915
1 parent 8992694
commit 9743915
Showing 1 changed file with 40 additions and 13 deletions.
diff --git a/graphql/src/graphql_schema.ml b/graphql/src/graphql_schema.ml
@@ -652,6 +652,18 @@ module Introspection = struct
         | DefaultArg a -> arg_types memo a.typ
         in arg_list_types memo' args
 
+  let types_of_schema s =
+    let types, _ =
+      List.fold_left
+      (fun memo op ->
+        match op with
+        | None -> memo
+        | Some op -> types ~memo (Object op))
+      ([], StringSet.empty)
+      [Some s.query; s.mutation; Option.map s.subscription ~f:obj_of_subscription_obj]
+    in
+    types
+
   let rec args_to_list : type a b. ?memo:any_arg list -> (a, b) Arg.arg_list -> any_arg list = fun ?memo:(memo=[]) arglist ->
     let open Arg in
     match arglist with
@@ -1146,16 +1158,7 @@ module Introspection = struct
         typ = NonNullable (List (NonNullable __type));
         args = Arg.[];
         lift = Io.ok;
-        resolve = fun _ s ->
-          let types, _ = List.fold_left
-            (fun memo op ->
-              match op with
-              | None -> memo
-              | Some op -> types ~memo (Object op))
-            ([], StringSet.empty)
-            [Some s.query; s.mutation; Option.map s.subscription ~f:obj_of_subscription_obj]
-          in
-          types
+        resolve = fun _ s -> types_of_schema s
       };
       Field {
         name = "queryType";
@@ -1197,7 +1200,7 @@ module Introspection = struct
     ]
   }
 
-  let add_schema_field s =
+  let add_built_in_fields s =
     let schema_field = Field {
       name = "__schema";
       doc = None;
@@ -1207,7 +1210,31 @@ module Introspection = struct
       lift = Io.ok;
       resolve = fun _ _ -> s
     } in
-    let fields = lazy (schema_field::(Lazy.force s.query.fields)) in
+    let type_field = Field {
+      name = "__type";
+      doc = None;
+      deprecated = NotDeprecated;
+      typ = __type;
+      args = Arg.[arg "name" ~typ:(non_null string)];
+      lift = Io.ok;
+      resolve = fun _ _ name ->
+        let types = types_of_schema s in
+        List.find (fun typ ->
+          match typ with
+          | AnyTyp (Object o) -> o.name = name
+          | AnyTyp (Scalar s) -> s.name = name
+          | AnyTyp (Enum e) -> e.name = name
+          | AnyTyp (Abstract a) -> a.name = name
+          | AnyArgTyp (Arg.Object o) -> o.name = name
+          | AnyArgTyp (Arg.Scalar s) -> s.name = name
+          | AnyArgTyp (Arg.Enum e) -> e.name = name
+          | AnyTyp (List _) -> false
+          | AnyTyp (NonNullable _) -> false
+          | AnyArgTyp (List _) -> false
+          | AnyArgTyp (NonNullable _) -> false
+        ) types
+    } in
+    let fields = lazy (schema_field::type_field::(Lazy.force s.query.fields)) in
     { s with query = { s.query with fields } }
 end
 
@@ -1570,7 +1597,7 @@ end
     let open Io.Infix in
     let execute' schema ctx doc =
       Io.return (collect_and_validate_fragments doc) >>=? fun fragments ->
-      let schema' = Introspection.add_schema_field schema in
+      let schema' = Introspection.add_built_in_fields schema in
       Io.return (select_operation ?operation_name doc) >>=? fun op ->
       let default_variables = List.fold_left (fun memo { Graphql_parser.name; default_value; _ } ->
         match default_value with