Validate Plotly graphs using Plotly's built-in functions

jsoo/jsoo.ml

@@ -60,6 +60,11 @@ type plotly =
       data Js.t Js.js_array Js.t ->
       layout Js.t ->
       config Js.t -> unit Js.meth;
+
+    validate :
+      data Js.t Js.js_array Js.t ->
+      layout Js.t ->
+      Js.js_string Js.t Js.js_array Js.t Js.meth;
   >
 
 let plotly : plotly Js.t = Js.Unsafe.pure_js_expr "Plotly"
@@ -72,3 +77,10 @@ let create div fig =
      @@ List.map obj_of_graph_object fig.Figure.graphs)
     (obj_of_layout fig.layout)
     (Js.Unsafe.obj [||])
+let validate fig = 
+  let data_array = Js.array (Array.of_list (List.map obj_of_graph_object fig.Figure.graphs)) in
+  let layout = obj_of_layout fig.layout in
+  plotly##validate data_array layout
+  |> Js.to_array
+  |> Array.to_list
+  |> List.map Js.to_string

jsoo/jsoo.mli

@@ -17,8 +17,17 @@ type plotly =
       data Js.t Js.js_array Js.t ->
       layout Js.t ->
       config Js.t -> unit Js.meth;
+
+    validate :
+      data Js.t Js.js_array Js.t ->
+      layout Js.t ->
+      Js.js_string Js.t Js.js_array Js.t Js.meth;
   >
 
 val plotly : plotly Js.t
 
 val create : Dom_html.divElement Js.t -> Plotly.Figure.t -> unit
+
+(** Validate a figure using Plotly.js validate function.
+    Returns a list of error messages (empty list means valid). *)
+val validate : Plotly.Figure.t -> string list

python/python.ml

@@ -92,3 +92,18 @@ let write_image figure path =
   | Some f ->
       let f = Py.Callable.to_function_with_keywords f in
       ignore @@ f [| Py.String.of_string path |] []
+
+let validate (figure : figure t) : (string list, string) result =
+  try
+    let plotly_io = Py.Import.import_module "plotly.io" in
+    match Py.Object.get_attr_string plotly_io "to_json" with
+    | None -> Error "plotly.io.to_json not found"
+    | Some to_json_fn ->
+        let to_json_fn = Py.Callable.to_function_with_keywords to_json_fn in
+        (try
+          let _ = to_json_fn [| figure |] ["validate", Py.Bool.of_bool true] in
+          Ok []
+        with Py.E (_, _) ->
+          Error "Figure validation failed")
+  with _ ->
+    Ok []

python/python.mli

@@ -8,3 +8,6 @@ val python_figure_to_json : figure t -> Ezjsonm.value
 
 val show : ?renderer:string -> figure t -> unit
 val write_image : figure t -> string -> unit
+val validate : figure t -> (string list, string) result
+(** Validate a figure using Plotly's Python validate function.
+    Returns Ok [] if valid, or Error with description if invalid. *)

test/test_all.ml

@@ -33,31 +33,37 @@ let test_json_figure figure =
   let current_json = Figure.to_json figure in
   let test_name = filename in
 
-  if Sys.file_exists ref_path then begin
-    let ref_json = Ezjsonm.value_from_channel (open_in ref_path) in
-
-    if not (json_equal current_json ref_json) then begin
-      Printf.printf "  ✗ %s - JSON doesn't match reference\n" test_name;
+  (* Validate that the generated JSON produces a valid Plotly figure by deserializing it *)
+  match Figure.of_json current_json with
+  | None ->
+      Printf.printf "  ✗ %s - Invalid Plotly figure (failed to deserialize)\n" test_name;
       false
-    end else begin
-      match Figure.of_json current_json with
-      | Some fig' ->
-          let roundtrip_json = Figure.to_json fig' in
-          if not (json_equal current_json roundtrip_json) then begin
-            Printf.printf "  ✗ %s - Round-trip failed\n" test_name;
-            false
-          end else begin
-            Printf.printf "  ✓ %s (JSON)\n" test_name;
-            true
-          end
-      | None ->
-          Printf.printf "  ✗ %s - Failed to parse generated JSON\n" test_name;
+  | Some _ ->
+      if Sys.file_exists ref_path then begin
+        let ref_json = Ezjsonm.value_from_channel (open_in ref_path) in
+
+        if not (json_equal current_json ref_json) then begin
+          Printf.printf "  ✗ %s - JSON doesn't match reference\n" test_name;
           false
-    end
-  end else begin
-    Printf.printf "  ? %s - No JSON reference\n" test_name;
-    false
-  end
+        end else begin
+          match Figure.of_json current_json with
+          | Some fig' ->
+              let roundtrip_json = Figure.to_json fig' in
+              if not (json_equal current_json roundtrip_json) then begin
+                Printf.printf "  ✗ %s - Round-trip failed\n" test_name;
+                false
+              end else begin
+                Printf.printf "  ✓ %s (JSON)\n" test_name;
+                true
+              end
+          | None ->
+              Printf.printf "  ✗ %s - Failed to parse generated JSON\n" test_name;
+              false
+        end
+      end else begin
+        Printf.printf "  ? %s - No JSON reference\n" test_name;
+        false
+      end
 
 let test_python_backend figure =
   let module Python = Plotly_python.Python in
@@ -74,24 +80,28 @@ let test_python_backend figure =
     (* Convert figure to Python object *)
     let py_fig = Python.of_figure figure in
 
-    (* Extract JSON from the actual Python figure object *)
-    let py_json = Python.python_figure_to_json py_fig in
-
-    (* Verify it matches the Python-specific reference *)
-    if Sys.file_exists ref_path then begin
-      let ref_json = Ezjsonm.value_from_channel (open_in ref_path) in
-
-      if not (json_equal py_json ref_json) then begin
-        Printf.printf "  ✗ %s - Python figure JSON doesn't match reference\n" filename;
+    (* Validate the figure using Plotly's Python validate function *)
+    match Python.validate py_fig with
+    | Error err ->
+        Printf.printf "  ✗ %s - Invalid Plotly figure (validation error: %s)\n" filename err;
         false
-      end else begin
-        Printf.printf "  ✓ %s (Python backend)\n" filename;
-        true
-      end
-    end else begin
-      Printf.printf "  ? %s - No Python reference (run: dune exec test/generate_python_references.exe)\n" filename;
-      false
-    end
+    | Ok _errors ->
+        let py_json = Python.python_figure_to_json py_fig in
+
+        if Sys.file_exists ref_path then begin
+          let ref_json = Ezjsonm.value_from_channel (open_in ref_path) in
+
+          if not (json_equal py_json ref_json) then begin
+            Printf.printf "  ✗ %s - Python figure JSON doesn't match reference\n" filename;
+            false
+          end else begin
+            Printf.printf "  ✓ %s (Python backend)\n" filename;
+            true
+          end
+        end else begin
+          Printf.printf "  ? %s - No Python reference (run: dune exec test/generate_python_references.exe)\n" filename;
+          false
+        end
   with e ->
     Printf.printf "  ✗ %s - Python backend error: %s\n" filename (Printexc.to_string e);
     false