Demonstrate form validation in examples

examples/sqla/views.py

@@ -14,7 +14,7 @@
 from starlette_admin.contrib.sqla import ModelView
 from starlette_admin.exceptions import ActionFailed, FormValidationError
 
-from .models import Post, Tag, User
+from .models import Post, User
 
 AVAILABLE_USER_TYPES = [
     ("admin", "Admin"),
@@ -68,6 +68,13 @@ async def validate(self, request: Request, data: Dict[str, Any]) -> None:
             raise FormValidationError(errors)
         return await super().validate(request, data)
 
+    async def validate_add_tag(self, request: Request, data: Dict[str, Any]):
+        errors: Dict[str, str] = {}
+        if data["tag"] is None:
+            errors["tag"] = "You must specify a tag"
+        if len(errors) > 0:
+            raise FormValidationError(errors)
+
     @action(
         name="add_tag",
         text="Add a tag for selected posts",
@@ -76,11 +83,22 @@ async def validate(self, request: Request, data: Dict[str, Any]) -> None:
         form_context={"form_fields": [HasOne("tag", identity="tag")]},
     )
     async def add_tag(self, request: Request, pks: List[Any]):
-        form = await request.form()
-        tag_pk = form["tag"]
-        tag = await TagView(Tag).find_by_pk(request, tag_pk)
-        if not tag:
-            raise ActionFailed("Tag is missing")
+        form_fields = [HasOne("tag", identity="tag")]
+        try:
+            form = (
+                await request.form()
+            )  # from starlette_admin.base.BaseAdmin._render_edit
+            data = {
+                f.name: f.parse_form_data(request, form, request.state.action)
+                for f in form_fields
+            }  # from starlette_admin.base.BaseAdmin.form_to_dict
+        except Exception as e:
+            raise ActionFailed(f"Form processing error: {e}") from e
+
+        data = await self.arrange_data_for_fields(request, data, form_fields)
+        await self.validate_add_tag(request, data)
+
+        tag = data["tag"]
         posts = await self.find_by_pks(request, pks)
         for post in posts:
             post.tags.append(tag)