Add basic request modification (#37)

README.md

@@ -327,6 +327,32 @@ class MyChange(VersionChange):
 
 ```
 
+#### Changing endpoint logic (Experimental)
+
+Oftentimes you change some of the logic of your endpoint in a way that is incompatible with or not yet supported by Universi's migrations. In order to combat this, we have come up with an ugly hack that allows you to change any detail about your endpoint's arguments or logic:
+
+```python
+from fastapi.params import Param
+from fastapi import Header
+
+
+class MyVersionChange(VersionChange):
+    description = "..."
+    instructions_to_migrate_to_previous_version = ()
+
+    @endpoint("/users", ["GET"]).was
+    def get_old_endpoint():
+        from some_business_logic import SomeController
+
+
+        async def get_users(some_old_parameter: str = Param(), some_new_required_header: str = Header()):
+            return SomeController(some_old_parameter, some_new_required_header)
+
+        return get_users
+```
+
+As you see, it's hacky in more ways than one. Any imports to your business logic must happen within the function to prevent circular dependencies and you have to have a function within a function as a result. It is therefore not advised to use this functionality unlesss absolutely required. I recommend to instead add an issue on our github. However, if Universi definitely cannot solve your problem -- this should be your "get out of jail free" card.
+
 #### Dealing with endpoint duplicates
 
 Sometimes, when you're doing some advanced changes in between versions, you will need to rewrite your endpoint function entirely. So essentially you'd have the following structure:
@@ -497,7 +523,7 @@ class MyChange(VersionChange):
 
 ```
 
-#### Rename a schema
+#### Rename a schema (Experimental)
 
 If you wish to rename your schema to make sure that its name is different in openapi.json:
 
@@ -512,8 +538,7 @@ class MyChange(VersionChange):
 
 ```
 
-which will replace all references to this schema with the new name. Note that this functionality is still experimental
-so minor issues can be expected. If you find any -- feel free to report it in issues.
+which will replace all references to this schema with the new name.
 
 Note also that renaming a schema should not technically be a breaking change.
 

pyproject.toml

@@ -1,6 +1,6 @@
 [tool.poetry]
 name = "universi"
-version = "1.9.1"
+version = "1.10.0.rc0"
 description = "Modern Stripe-like API versioning in FastAPI"
 authors = ["Stanislav Zmiev <zmievsa@gmail.com>"]
 license = "MIT"

tests/_data/utils.py

@@ -0,0 +1,2 @@
+def some_fastapi_dependency(hi: str = "hellow"):
+    return hi

tests/test_routing.py

@@ -5,7 +5,7 @@
 from typing import Annotated, Any, NewType, TypeAlias, cast, get_args
 
 import pytest
-from fastapi import APIRouter, Body, Depends, FastAPI
+from fastapi import APIRouter, Body, Depends, FastAPI, Header
 from fastapi.routing import APIRoute
 from fastapi.testclient import TestClient
 from pydantic import BaseModel
@@ -38,14 +38,14 @@ def router() -> VersionedAPIRouter:
 
 @pytest.fixture()
 def test_path() -> str:
-    return "/test/{hewoo}"
+    return "/test/{hewwo}"
 
 
 @pytest.fixture()
 def test_endpoint(router: VersionedAPIRouter, test_path: str) -> Endpoint:
     @router.get(test_path)
     async def test(hewwo: int):
-        raise NotImplementedError
+        return hewwo
 
     return test
 
@@ -94,9 +94,6 @@ def __call__(
         latest_schemas_module: Any = Default,
     ) -> tuple[list[APIRoute], list[APIRoute]]:
         routers = self.create_versioned_copies(*instructions, latest_schemas_module=latest_schemas_module)
-        for router in routers.values():
-            for route in router.routes:
-                assert isinstance(route, APIRoute)
         return cast(
             tuple[list[APIRoute], list[APIRoute]],
             (routers[date(2000, 1, 1)].routes, routers[date(2001, 1, 1)].routes),
@@ -310,7 +307,7 @@ def test__router_generation__re_creating_an_existing_endpoint__error(
     with pytest.raises(
         RouterGenerationError,
         match=re.escape(
-            "Endpoint \"['GET'] /test/{hewoo}\" you tried to restore in "
+            "Endpoint \"['GET'] /test/{hewwo}\" you tried to restore in "
             '"MyVersionChange" already existed in a newer version',
         ),
     ):
@@ -324,7 +321,7 @@ def test__router_generation__editing_an_endpoint_with_wrong_method__should_raise
 ):
     with pytest.raises(
         RouterGenerationError,
-        match=re.escape('Endpoint "[\'POST\'] /test/{hewoo}" you tried to change in "MyVersionChange" doesn\'t exist'),
+        match=re.escape('Endpoint "[\'POST\'] /test/{hewwo}" you tried to change in "MyVersionChange" doesn\'t exist'),
     ):
         create_versioned_copies(endpoint(test_path, ["POST"]).had(description="Hewwo"))
 
@@ -333,27 +330,27 @@ def test__router_generation__editing_an_endpoint_with_a_less_general_method__sho
     router: VersionedAPIRouter,
     create_versioned_copies: CreateVersionedCopies,
 ):
-    @router.route("/test/{hewoo}", methods=["GET", "POST"])
+    @router.route("/test/{hewwo}", methods=["GET", "POST"])
     async def test(hewwo: int):
         raise NotImplementedError
 
     with pytest.raises(
         RouterGenerationError,
-        match=re.escape('Endpoint "[\'GET\'] /test/{hewoo}" you tried to change in "MyVersionChange" doesn\'t exist'),
+        match=re.escape('Endpoint "[\'GET\'] /test/{hewwo}" you tried to change in "MyVersionChange" doesn\'t exist'),
     ):
-        create_versioned_copies(endpoint("/test/{hewoo}", ["GET"]).had(description="Hewwo"))
+        create_versioned_copies(endpoint("/test/{hewwo}", ["GET"]).had(description="Hewwo"))
 
 
 def test__router_generation__editing_multiple_endpoints_with_same_route(
     router: VersionedAPIRouter,
     create_versioned_api_routes: CreateVersionedAPIRoutes,
 ):
-    @router.api_route("/test/{hewoo}", methods=["GET", "POST"])
+    @router.api_route("/test/{hewwo}", methods=["GET", "POST"])
     async def test(hewwo: int):
         raise NotImplementedError
 
     routes_2000, routes_2001 = create_versioned_api_routes(
-        endpoint("/test/{hewoo}", ["GET", "POST"]).had(description="Meaw"),
+        endpoint("/test/{hewwo}", ["GET", "POST"]).had(description="Meaw"),
     )
     assert len(routes_2000) == len(routes_2001) == 1
     assert routes_2000[0].description == "Meaw"
@@ -367,7 +364,7 @@ def test__router_generation__editing_an_endpoint_with_a_more_general_method__sho
 ):
     with pytest.raises(
         RouterGenerationError,
-        match=re.escape('Endpoint "[\'POST\'] /test/{hewoo}" you tried to change in "MyVersionChange" doesn\'t exist'),
+        match=re.escape('Endpoint "[\'POST\'] /test/{hewwo}" you tried to change in "MyVersionChange" doesn\'t exist'),
     ):
         create_versioned_copies(endpoint(test_path, ["GET", "POST"]).had(description="Hewwo"))
 
@@ -582,7 +579,7 @@ def test__router_generation__changing_attribute_to_the_same_value__error(
     with pytest.raises(
         RouterGenerationError,
         match=re.escape(
-            'Expected attribute "path" of endpoint "[\'GET\'] /test/{hewoo}" to be different in "MyVersionChange", but '
+            'Expected attribute "path" of endpoint "[\'GET\'] /test/{hewwo}" to be different in "MyVersionChange", but '
             "it was the same. It means that your version change has no effect on the attribute and can be removed.",
         ),
     ):
@@ -993,3 +990,43 @@ class V2001(VersionChange):
     }
     assert routers[date(2000, 1, 1)].routes[0].endpoint.func == test_endpoint2
     assert routers[date(2000, 1, 1)].routes[0].endpoint.func == test_endpoint2
+
+
+def test__router_generation__adding_request_header_using_hacks(
+    router: VersionedAPIRouter,
+    test_endpoint: Endpoint,
+    test_path: str,
+    api_version_var: ContextVar[date | None],
+):
+    class MyVersionChange(VersionChange):
+        description = "..."
+        instructions_to_migrate_to_previous_version = ()
+
+        @endpoint(test_path, ["GET"]).was
+        def get_old_endpoint():
+            from tests._data.utils import some_fastapi_dependency
+
+            async def test_endpoint(hewwo: int, header: str = Header(), dep: str = Depends(some_fastapi_dependency)):
+                return {"hewwo": hewwo, "header": header, "dep": dep}
+
+            return test_endpoint
+
+    versions = generate_all_router_versions(
+        router,
+        versions=VersionBundle(
+            Version(date(2001, 1, 1), MyVersionChange),
+            Version(date(2000, 1, 1)),
+            api_version_var=api_version_var,
+        ),
+        latest_schemas_module=None,
+    )
+
+    client_2000 = client(versions[date(2000, 1, 1)])
+    client_2001 = client(versions[date(2001, 1, 1)])
+
+    assert client_2000.get("/test/83", headers={"header": "11"}, params={"hi": "Mark"}).json() == {
+        "hewwo": 83,
+        "header": "11",
+        "dep": "Mark",
+    }
+    assert client_2001.get("/test/83", params={"header": 11, "hi": "Mark"}).json() == 83

tests/test_tutorial/test_users_example001/run.py

@@ -1,7 +1,5 @@
-from universi.routing import generate_all_router_versions
-
-
 if __name__ == "__main__":
+    from universi.routing import generate_all_router_versions
     from datetime import date
     from pathlib import Path
 

tests/test_tutorial/test_users_example002/run.py

@@ -1,7 +1,5 @@
-from universi.routing import generate_all_router_versions
-
-
 if __name__ == "__main__":
+    from universi.routing import generate_all_router_versions
     from datetime import date
     from pathlib import Path
 

universi/codegen.py

@@ -186,7 +186,7 @@ def _get_union_of_versioned_name(
     if isinstance(node, ast.ClassDef):
         # We add [schemas_per_version[0]] because imported_modules include "latest" and schemas_per_version do not
         union = " | ".join(
-            f"{module.alias}.{_get_mod_name(node, module, schemas)}"
+            f"{module.alias}.{_get_modified_name_of_ast_node(node, module, schemas)}"
             for module, schemas in zip(imported_modules, [schemas_per_version[0], *schemas_per_version])
         )
         return ast.Name(
@@ -196,7 +196,7 @@ def _get_union_of_versioned_name(
         return node
 
 
-def _get_mod_name(node: ast.ClassDef, module: ImportedModule, schemas: dict[str, ModelInfo]):
+def _get_modified_name_of_ast_node(node: ast.ClassDef, module: ImportedModule, schemas: dict[str, ModelInfo]):
     node_python_path = f"{module.absolute_python_path_to_origin}.{node.name}"
     if node_python_path in schemas:
         return schemas[node_python_path].name

universi/routing.py

@@ -1,7 +1,6 @@
 import datetime
 import functools
 import inspect
-import itertools
 import typing
 import warnings
 from collections.abc import Callable, Sequence
@@ -59,6 +58,7 @@
     EndpointDidntExistInstruction,
     EndpointExistedInstruction,
     EndpointHadInstruction,
+    EndpointWasInstruction,
 )
 from universi.structure.versions import VersionChange
 
@@ -243,6 +243,15 @@ def _apply_endpoint_changes_to_router(self, router: fastapi.routing.APIRouter, v
                         'Endpoint "{endpoint_methods} {endpoint_path}" you tried to change in'
                         ' "{version_change_name}" doesn\'t exist'
                     )
+                elif isinstance(instruction, EndpointWasInstruction):
+                    for original_route in original_routes:
+                        methods_to_which_we_applied_changes |= original_route.methods
+                        original_route.endpoint = instruction.get_old_endpoint()
+                        _remake_endpoint_dependencies(original_route)
+                    err = (
+                        'Endpoint "{endpoint_methods} {endpoint_path}" whose handler you tried to change in'
+                        ' "{version_change_name}" doesn\'t exist'
+                    )
                 else:
                     assert_never(instruction)
                 method_diff = methods_we_should_have_applied_changes_to - methods_to_which_we_applied_changes
@@ -317,14 +326,7 @@ def migrate_router_to_version(self, router: fastapi.routing.APIRouter, version:
                 route.response_model = self._change_version_of_annotations(route.response_model, version_dir)
             route.dependencies = self._change_version_of_annotations(route.dependencies, version_dir)
             route.endpoint = self._change_version_of_annotations(route.endpoint, version_dir)
-            route.dependant = get_dependant(path=route.path_format, call=route.endpoint)
-            route.body_field = get_body_field(dependant=route.dependant, name=route.unique_id)
-            for depends in route.dependencies[::-1]:
-                route.dependant.dependencies.insert(
-                    0,
-                    get_parameterless_sub_dependant(depends=depends, path=route.path_format),
-                )
-            route.app = request_response(route.get_route_handler())
+            _remake_endpoint_dependencies(route)
 
     def _change_versions_of_a_non_container_annotation(self, annotation: Any, version_dir: Path) -> Any:
         if isinstance(annotation, _BaseGenericAlias | GenericAlias):
@@ -438,6 +440,17 @@ def _change_version_of_type(self, annotation: type, version_dir: Path):
             return annotation
 
 
+def _remake_endpoint_dependencies(route: fastapi.routing.APIRoute):
+    route.dependant = get_dependant(path=route.path_format, call=route.endpoint)
+    route.body_field = get_body_field(dependant=route.dependant, name=route.unique_id)
+    for depends in route.dependencies[::-1]:
+        route.dependant.dependencies.insert(
+            0,
+            get_parameterless_sub_dependant(depends=depends, path=route.path_format),
+        )
+    route.app = request_response(route.get_route_handler())
+
+
 def _add_data_migrations_to_all_routes(router: fastapi.routing.APIRouter, versions: VersionBundle):
     for route in router.routes:
         if isinstance(route, fastapi.routing.APIRoute):

universi/structure/endpoints.py

@@ -1,7 +1,7 @@
 from collections.abc import Callable, Sequence
 from dataclasses import dataclass
 from enum import Enum
-from typing import Any
+from typing import Any, cast
 
 from fastapi import Response
 from fastapi.params import Depends
@@ -71,6 +71,14 @@ class EndpointDidntExistInstruction:
     endpoint_func_name: str | None
 
 
+@dataclass(slots=True)
+class EndpointWasInstruction:
+    endpoint_path: str
+    endpoint_methods: Sequence[str]
+    endpoint_func_name: str | None
+    get_old_endpoint: Callable[..., Any]
+
+
 @dataclass(slots=True)
 class EndpointInstructionFactory:
     endpoint_path: str
@@ -138,6 +146,17 @@ def had(
             ),
         )
 
+    def was(self, get_old_endpoint: Callable[[], Any]) -> type[staticmethod]:
+        return cast(
+            type[staticmethod],
+            EndpointWasInstruction(
+                endpoint_path=self.endpoint_path,
+                endpoint_methods=self.endpoint_methods,
+                endpoint_func_name=self.endpoint_func_name,
+                get_old_endpoint=get_old_endpoint,
+            ),
+        )
+
 
 def endpoint(path: str, methods: list[str], /, *, func_name: str | None = None) -> EndpointInstructionFactory:
     return EndpointInstructionFactory(path, methods, func_name)

universi/structure/versions.py

@@ -10,7 +10,7 @@
 from typing_extensions import assert_never
 
 from universi.exceptions import UniversiError, UniversiStructureError
-from universi.structure.endpoints import AlterEndpointSubInstruction
+from universi.structure.endpoints import AlterEndpointSubInstruction, EndpointWasInstruction
 from universi.structure.enums import AlterEnumSubInstruction
 
 from .._utils import Sentinel
@@ -30,7 +30,7 @@ class VersionChange:
     instructions_to_migrate_to_previous_version: ClassVar[Sequence[PossibleInstructions]] = Sentinel
     alter_schema_instructions: ClassVar[Sequence[AlterSchemaSubInstruction | AlterSchemaInstruction]] = Sentinel
     alter_enum_instructions: ClassVar[Sequence[AlterEnumSubInstruction]] = Sentinel
-    alter_endpoint_instructions: ClassVar[Sequence[AlterEndpointSubInstruction]] = Sentinel
+    alter_endpoint_instructions: ClassVar[Sequence[AlterEndpointSubInstruction | EndpointWasInstruction]] = Sentinel
     alter_response_instructions: ClassVar[dict[Any, AlterResponseInstruction]] = Sentinel
     alter_request_instructions: ClassVar[dict[Any, list[AlterRequestInstruction]]] = Sentinel
     _bound_versions: "VersionBundle | None"
@@ -59,6 +59,8 @@ def __init_subclass__(cls, _abstract: bool = False) -> None:
                 cls.alter_schema_instructions.append(instruction)
             elif isinstance(instruction, AlterResponseInstruction):
                 cls.alter_response_instructions[instruction.schema] = instruction
+            elif isinstance(instruction, EndpointWasInstruction):
+                cls.alter_endpoint_instructions.append(instruction)
 
         cls._check_no_subclassing()
         cls._bound_versions = None
@@ -86,7 +88,7 @@ def _validate_subclass(cls):
         for attr_name, attr_value in cls.__dict__.items():
             if not isinstance(
                 attr_value,
-                AlterResponseInstruction | SchemaPropertyDefinitionInstruction,
+                AlterResponseInstruction | SchemaPropertyDefinitionInstruction | EndpointWasInstruction,
             ) and attr_name not in {
                 "description",
                 "side_effects",