Allow using related model fields in list/details page

docs/configurations.md

@@ -110,7 +110,7 @@ or list of the tuple for multiple columns.
 
     ```python
     class UserAdmin(ModelView, model=User):
-        column_list = [User.id, User.name]
+        column_list = [User.id, User.name, "user.address.zip_code"]
         column_searchable_list = [User.name]
         column_sortable_list = [User.id]
         column_formatters = {User.name: lambda m, a: m.name[:10]}
@@ -138,10 +138,16 @@ The options available are:
 
     ```python
     class UserAdmin(ModelView, model=User):
-        column_details_list = [User.id, User.name]
+        column_details_list = [User.id, User.name, "user.address.zip_code"]
         column_formatters_detail = {User.name: lambda m, a: m.name[:10]}
     ```
 
+!!! tip
+
+    You can show related model's attributes by using a string value. For example
+    "user.address.zip_code" will load the relationship but it will trigger extra queries for each
+    relationship loading.
+
 ## Pagination options
 
 The pagination options in the list page can be configured. The available options include:

sqladmin/models.py

@@ -21,6 +21,7 @@
 from sqlalchemy import Column, String, asc, cast, desc, func, inspect, or_
 from sqlalchemy.exc import NoInspectionAvailable
 from sqlalchemy.orm import joinedload, sessionmaker
+from sqlalchemy.orm.exc import DetachedInstanceError
 from sqlalchemy.sql.elements import ClauseElement
 from sqlalchemy.sql.expression import Select, select
 from starlette.datastructures import URL
@@ -702,22 +703,6 @@ async def _run_query(self, stmt: ClauseElement) -> Any:
         else:
             return await anyio.to_thread.run_sync(self._run_query_sync, stmt)
 
-    def _url_for_details(self, request: Request, obj: Any) -> Union[str, URL]:
-        pk = get_object_identifier(obj)
-        return request.url_for(
-            "admin:details",
-            identity=slugify_class_name(obj.__class__.__name__),
-            pk=pk,
-        )
-
-    def _url_for_edit(self, request: Request, obj: Any) -> Union[str, URL]:
-        pk = get_object_identifier(obj)
-        return request.url_for(
-            "admin:edit",
-            identity=slugify_class_name(obj.__class__.__name__),
-            pk=pk,
-        )
-
     def _url_for_delete(self, request: Request, obj: Any) -> str:
         pk = get_object_identifier(obj)
         query_params = urlencode({"pks": pk})
@@ -726,24 +711,20 @@ def _url_for_delete(self, request: Request, obj: Any) -> str:
         )
         return str(url) + "?" + query_params
 
-    def _url_for_details_with_prop(
-        self, request: Request, obj: Any, prop: str
-    ) -> Union[str, URL]:
-        target = getattr(obj, prop)
+    def _url_for_details_with_prop(self, request: Request, obj: Any, prop: str) -> URL:
+        target = getattr(obj, prop, None)
         if target is None:
-            return ""
-
-        return request.url_for(
-            "admin:details",
-            identity=slugify_class_name(target.__class__.__name__),
-            pk=get_object_identifier(target),
-        )
+            return URL()
+        return self._build_url_for("admin:details", request, target)
 
     def _url_for_action(self, request: Request, action_name: str) -> str:
-        return str(
-            request.url_for(
-                f"admin:action-{self.identity}-{action_name}",
-            )
+        return str(request.url_for(f"admin:action-{self.identity}-{action_name}"))
+
+    def _build_url_for(self, name: str, request: Request, obj: Any) -> URL:
+        return request.url_for(
+            name,
+            identity=slugify_class_name(obj.__class__.__name__),
+            pk=get_object_identifier(obj),
         )
 
     def _get_default_sort(self) -> List[Tuple[str, bool]]:
@@ -846,32 +827,45 @@ def _stmt_by_identifier(self, identifier: str) -> Select:
         return stmt.where(*conditions)
 
     async def get_prop_value(self, obj: Any, prop: str) -> Any:
-        result = getattr(obj, prop, None)
-        if result and isinstance(result, Enum):
-            result = result.name
+        for part in prop.split("."):
+            try:
+                obj = getattr(obj, part, None)
+            except DetachedInstanceError:
+                obj = await self._lazyload_prop(obj, part)
+
+        if obj and isinstance(obj, Enum):
+            obj = obj.name
+
+        return obj
 
-        return result
+    async def _lazyload_prop(self, obj: Any, prop: str) -> Any:
+        if self.is_async:
+            async with self.session_maker() as session:
+                session.add(obj)
+                return await session.run_sync(lambda sess: getattr(obj, prop))
+        else:
+            with self.session_maker() as session:
+                session.add(obj)
+                return await anyio.to_thread.run_sync(lambda: getattr(obj, prop))
 
     async def get_list_value(self, obj: Any, prop: str) -> Tuple[Any, Any]:
         """Get tuple of (value, formatted_value) for the list view."""
 
         value = await self.get_prop_value(obj, prop)
-        formatted_value = self._default_formatter(value)
-
         formatter = self._list_formatters.get(prop)
-        if formatter:
-            formatted_value = formatter(obj, prop)
+        formatted_value = (
+            formatter(obj, prop) if formatter else self._default_formatter(value)
+        )
         return value, formatted_value
 
     async def get_detail_value(self, obj: Any, prop: str) -> Tuple[Any, Any]:
         """Get tuple of (value, formatted_value) for the detail view."""
 
         value = await self.get_prop_value(obj, prop)
-        formatted_value = self._default_formatter(value)
-
         formatter = self._detail_formatters.get(prop)
-        if formatter:
-            formatted_value = formatter(obj, prop)
+        formatted_value = (
+            formatter(obj, prop) if formatter else self._default_formatter(value)
+        )
         return value, formatted_value
 
     def _build_column_list(

sqladmin/templates/details.html

@@ -28,7 +28,7 @@ <h3 class="card-title">
               {% if is_list( value ) %}
               <td>
               {% for elem, formatted_elem in zip(value, formatted_value) %}
-              <a href="{{ model_view._url_for_details(request, elem) }}">({{ formatted_elem }})</a>
+              <a href="{{ model_view._build_url_for('admin:details', request, elem) }}">({{ formatted_elem }})</a>
               {% endfor %}
               </td>
               {% else %}
@@ -58,7 +58,7 @@ <h3 class="card-title">
           {% endif %}
           {% if model_view.can_edit %}
           <div class="col-md-1">
-            <a href="{{ model_view._url_for_edit(request, model) }}" class="btn btn-primary">
+            <a href="{{ model_view._build_url_for('admin:edit', request, model) }}" class="btn btn-primary">
               Edit
             </a>
           </div>

sqladmin/templates/edit.html

@@ -6,7 +6,7 @@
       <h3 class="card-title">Edit {{ model_view.name }}</h3>
     </div>
     <div class="card-body border-bottom py-3">
-      <form action="{{ model_view._url_for_edit(request, obj) }}" method="POST" enctype="multipart/form-data">
+      <form action="{{ model_view._build_url_for('admin:edit', request, obj) }}" method="POST" enctype="multipart/form-data">
         <fieldset class="form-fieldset">
           {% for field in form %}
           <div class="mb-3 form-group row">

sqladmin/templates/list.html

@@ -105,12 +105,12 @@ <h3 class="card-title">{{ model_view.name_plural }}</h3>
             </td>
             <td class="text-end">
               {% if model_view.can_view_details %}
-              <a href="{{ model_view._url_for_details(request, row) }}" data-bs-toggle="tooltip" data-bs-placement="top" title="View">
+              <a href="{{ model_view._build_url_for('admin:details', request, row) }}" data-bs-toggle="tooltip" data-bs-placement="top" title="View">
                 <span class="me-1"><i class="fa-solid fa-eye"></i></span>
               </a>
               {% endif %}
               {% if model_view.can_edit %}
-              <a href="{{ model_view._url_for_edit(request, row) }}" data-bs-toggle="tooltip" data-bs-placement="top" title="Edit">
+              <a href="{{ model_view._build_url_for('admin:edit', request, row) }}" data-bs-toggle="tooltip" data-bs-placement="top" title="Edit">
                 <span class="me-1"><i class="fa-solid fa-pen-to-square"></i></span>
               </a>
               {% endif %}
@@ -126,7 +126,7 @@ <h3 class="card-title">{{ model_view.name_plural }}</h3>
             {% if is_list( value ) %}
             <td>
             {% for elem, formatted_elem in zip(value, formatted_value) %}
-            <a href="{{ model_view._url_for_details(request, elem) }}">({{ formatted_elem }})</a>
+            <a href="{{ model_view._build_url_for('admin:details', request, elem) }}">({{ formatted_elem }})</a>
             {% endfor %}
             </td>
             {% else %}

tests/test_models.py

@@ -1,6 +1,5 @@
 import enum
 from typing import Generator
-from unittest.mock import Mock, call, patch
 
 import pytest
 from markupsafe import Markup
@@ -382,27 +381,6 @@ def list_query(self, request: Request) -> Select:
     assert len(await view.get_model_objects(request)) == 1
 
 
-def test_url_for() -> None:
-    class UserAdmin(ModelView, model=User):
-        ...
-
-    view = UserAdmin()
-    request = Request({"type": "http"})
-    user = User(id=1)
-    address = Address(pk=2, user=user)
-
-    with patch("starlette.requests.Request.url_for", Mock()) as mock:
-        view._url_for_details(request, user)
-        view._url_for_edit(request, address)
-        view._url_for_delete(request, address)
-
-    assert mock.call_args_list == [
-        call("admin:details", identity="user", pk=1),
-        call("admin:edit", identity="address", pk=2),
-        call("admin:delete", identity="address"),
-    ]
-
-
 def test_model_columns_all_keyword() -> None:
     class AddressAdmin(ModelView, model=Address):
         column_list = "__all__"
@@ -414,13 +392,21 @@ class AddressAdmin(ModelView, model=Address):
 
 async def test_get_prop_value() -> None:
     class ProfileAdmin(ModelView, model=Profile):
-        ...
+        session_maker = session_maker
 
-    profile = Profile(is_active=True, role=Role.ADMIN, status=Status.ACTIVE)
+    with session_maker() as session:
+        user = User(name="admin")
+        address = Address(user=user)
+        profile = Profile(
+            is_active=True, role=Role.ADMIN, status=Status.ACTIVE, user=user
+        )
+        session.add_all([user, address, profile])
+        session.commit()
 
     assert await ProfileAdmin().get_prop_value(profile, "is_active") is True
     assert await ProfileAdmin().get_prop_value(profile, "role") == "ADMIN"
     assert await ProfileAdmin().get_prop_value(profile, "status") == "ACTIVE"
+    assert await ProfileAdmin().get_prop_value(profile, "user.name") == "admin"
 
 
 async def test_model_property_in_columns() -> None:

tests/test_views/test_view_async.py

@@ -161,7 +161,7 @@ class UserAdmin(ModelView, model=User):
 
 
 class AddressAdmin(ModelView, model=Address):
-    column_list = ["id", "user_id", "user"]
+    column_list = ["id", "user_id", "user", "user.name"]
     name_plural = "Addresses"
     export_max_rows = 3
 

tests/test_views/test_view_sync.py

@@ -153,7 +153,7 @@ class UserAdmin(ModelView, model=User):
 
 
 class AddressAdmin(ModelView, model=Address):
-    column_list = ["id", "user_id", "user"]
+    column_list = ["id", "user_id", "user", "user.name"]
     name_plural = "Addresses"
     export_max_rows = 3