fix: yield form in fastui_form to keep file handler open

src/python-fastui/fastui/forms.py

@@ -1,5 +1,6 @@
 import json
 import typing as _t
+from contextlib import asynccontextmanager
 from itertools import groupby
 from mimetypes import MimeTypes
 from operator import itemgetter
@@ -34,17 +35,18 @@ def __class_getitem__(cls, model: _t.Type[FormModel]) -> fastapi_params.Depends:
 
 
 def fastui_form(model: _t.Type[FormModel]) -> fastapi_params.Depends:
+    @asynccontextmanager
     async def run_fastui_form(request: fastapi.Request):
         async with request.form() as form_data:
             model_data = unflatten(form_data)
 
-        try:
-            return model.model_validate(model_data)
-        except pydantic.ValidationError as e:
-            raise fastapi.HTTPException(
-                status_code=422,
-                detail={'form': e.errors(include_input=False, include_url=False, include_context=False)},
-            )
+            try:
+                yield model.model_validate(model_data)
+            except pydantic.ValidationError as e:
+                raise fastapi.HTTPException(
+                    status_code=422,
+                    detail={'form': e.errors(include_input=False, include_url=False, include_context=False)},
+                )
 
     return fastapi.Depends(run_fastui_form)
 

src/python-fastui/tests/test_forms.py

@@ -27,6 +27,9 @@ def __init__(self, form_data_list: List[Tuple[str, Union[str, UploadFile]]]):
     @asynccontextmanager
     async def form(self):
         yield self._form_data
+        for value in self._form_data.values():
+            if isinstance(value, UploadFile):
+                value.file.close()
 
 
 def test_simple_form_fields():
@@ -94,9 +97,9 @@ async def test_simple_form_submit():
 
     request = FakeRequest([('name', 'bar'), ('size', '123')])
 
-    m = await form_dep.dependency(request)
-    assert isinstance(m, SimpleForm)
-    assert m.model_dump() == {'name': 'bar', 'size': 123}
+    async with form_dep.dependency(request) as m:
+        assert isinstance(m, SimpleForm)
+        assert m.model_dump() == {'name': 'bar', 'size': 123}
 
 
 async def test_simple_form_submit_repeat():
@@ -105,7 +108,8 @@ async def test_simple_form_submit_repeat():
     request = FakeRequest([('name', 'bar'), ('size', '123'), ('size', '456')])
 
     with pytest.raises(HTTPException) as exc_info:
-        await form_dep.dependency(request)
+        async with form_dep.dependency(request):
+            pass
 
     # insert_assert(exc_info.value.detail)
     assert exc_info.value.detail == {
@@ -156,9 +160,9 @@ async def test_w_nested_form_submit():
 
     request = FakeRequest([('name', 'bar'), ('nested.x', '123')])
 
-    m = await form_dep.dependency(request)
-    assert isinstance(m, FormWithNested)
-    assert m.model_dump() == {'name': 'bar', 'nested': {'x': 123}}
+    async with form_dep.dependency(request) as m:
+        assert isinstance(m, FormWithNested)
+        assert m.model_dump() == {'name': 'bar', 'nested': {'x': 123}}
 
 
 class FormWithFile(BaseModel):
@@ -190,8 +194,9 @@ async def test_file_submit():
     file = UploadFile(BytesIO(b'foobar'), size=6, filename='testing.txt')
     request = FakeRequest([('profile_pic', file)])
 
-    m = await fastui_form(FormWithFile).dependency(request)
-    assert m.model_dump() == {'profile_pic': file}
+    async with fastui_form(FormWithFile).dependency(request) as m:
+        assert m.model_dump() == {'profile_pic': file}
+        assert not m.profile_pic.file.closed
 
 
 async def test_file_submit_repeat():
@@ -200,7 +205,8 @@ async def test_file_submit_repeat():
     request = FakeRequest([('profile_pic', file1), ('profile_pic', file2)])
 
     with pytest.raises(HTTPException) as exc_info:
-        await fastui_form(FormWithFile).dependency(request)
+        async with fastui_form(FormWithFile).dependency(request):
+            pass
 
     # insert_assert(exc_info.value.detail)
     assert exc_info.value.detail == {
@@ -239,16 +245,18 @@ async def test_file_constrained_submit():
     file = UploadFile(BytesIO(b'foobar'), size=16_000, headers=headers)
     request = FakeRequest([('profile_pic', file)])
 
-    m = await fastui_form(FormWithFileConstraint).dependency(request)
-    assert m.model_dump() == {'profile_pic': file}
+    async with fastui_form(FormWithFileConstraint).dependency(request) as m:
+        assert m.model_dump() == {'profile_pic': file}
+        assert not m.profile_pic.file.closed
 
 
 async def test_file_constrained_submit_filename():
     file = UploadFile(BytesIO(b'foobar'), size=16_000, filename='image.png')
     request = FakeRequest([('profile_pic', file)])
 
-    m = await fastui_form(FormWithFileConstraint).dependency(request)
-    assert m.model_dump() == {'profile_pic': file}
+    async with fastui_form(FormWithFileConstraint).dependency(request) as m:
+        assert m.model_dump() == {'profile_pic': file}
+        assert not m.profile_pic.file.closed
 
 
 async def test_file_constrained_submit_too_big():
@@ -257,7 +265,8 @@ async def test_file_constrained_submit_too_big():
     request = FakeRequest([('profile_pic', file)])
 
     with pytest.raises(HTTPException) as exc_info:
-        await fastui_form(FormWithFileConstraint).dependency(request)
+        async with fastui_form(FormWithFileConstraint).dependency(request):
+            pass
 
     # insert_assert(exc_info.value.detail)
     assert exc_info.value.detail == {
@@ -277,7 +286,8 @@ async def test_file_constrained_submit_wrong_type():
     request = FakeRequest([('profile_pic', file)])
 
     with pytest.raises(HTTPException) as exc_info:
-        await fastui_form(FormWithFileConstraint).dependency(request)
+        async with fastui_form(FormWithFileConstraint).dependency(request):
+            pass
 
     # insert_assert(exc_info.value.detail)
     assert exc_info.value.detail == {
@@ -323,17 +333,20 @@ async def test_multiple_files_single():
     file = UploadFile(BytesIO(b'foobar'), size=16_000, filename='image.png')
     request = FakeRequest([('files', file)])
 
-    m = await fastui_form(FormMultipleFiles).dependency(request)
-    assert m.model_dump() == {'files': [file]}
+    async with fastui_form(FormMultipleFiles).dependency(request) as m:
+        assert m.model_dump() == {'files': [file]}
+        assert not m.files[0].file.closed
 
 
 async def test_multiple_files_multiple():
     file1 = UploadFile(BytesIO(b'foobar'), size=6, filename='image1.png')
     file2 = UploadFile(BytesIO(b'foobar'), size=6, filename='image2.png')
     request = FakeRequest([('files', file1), ('files', file2)])
 
-    m = await fastui_form(FormMultipleFiles).dependency(request)
-    assert m.model_dump() == {'files': [file1, file2]}
+    async with fastui_form(FormMultipleFiles).dependency(request) as m:
+        assert m.model_dump() == {'files': [file1, file2]}
+        assert not m.files[0].file.closed
+        assert not m.files[1].file.closed
 
 
 class FixedTuple(BaseModel):
@@ -379,8 +392,8 @@ def test_fixed_tuple():
 async def test_fixed_tuple_submit():
     request = FakeRequest([('foo.0', 'bar'), ('foo.1', '123'), ('foo.2', '456')])
 
-    m = await fastui_form(FixedTuple).dependency(request)
-    assert m.model_dump() == {'foo': ('bar', 123, 456)}
+    async with fastui_form(FixedTuple).dependency(request) as m:
+        assert m.model_dump() == {'foo': ('bar', 123, 456)}
 
 
 class NestedTuple(BaseModel):
@@ -426,8 +439,8 @@ def test_fixed_tuple_nested():
 async def test_fixed_tuple_nested_submit():
     request = FakeRequest([('bar.foo.0', 'bar'), ('bar.foo.1', '123'), ('bar.foo.2', '456')])
 
-    m = await fastui_form(NestedTuple).dependency(request)
-    assert m.model_dump() == {'bar': {'foo': ('bar', 123, 456)}}
+    async with fastui_form(NestedTuple).dependency(request) as m:
+        assert m.model_dump() == {'bar': {'foo': ('bar', 123, 456)}}
 
 
 def test_variable_tuple():