dmr-from-django-ninja

DMR from django-ninja

Overview

Migrate django-ninja / ninja-extra transport layer to django-modern-rest incrementally. Keep business logic unchanged unless user explicitly asks.

Required docs (always reference first):

• DMR LLM docs: https://django-modern-rest.readthedocs.io/llms-full.txt
• Local map: references/ninja-to-dmr-map.md

Migration Policy

• Default mode: strict transport parity.
• Preserve by default: paths, methods, request/response schemas, status codes, headers, auth semantics, throttling semantics.
• If user approves drift (for example switching to DMR-native error format/status), stop forcing legacy behavior and document this as approved drift.
• Never mix implicit drift: every intentional mismatch must be explicitly listed.
• Do not preserve Ninja infrastructure internals as implementation strategy. Keep observable contracts, but realize them with DMR + project-native libraries.

Workflow

Inventory Ninja surface

• Read project API entrypoints and URL wiring first.
• Find usages of: NinjaExtraAPI, api_controller, http_get/http_post/..., ninja.Schema, ninja_jwt, Ninja exception handlers, Ninja throttles.
• Build per-endpoint migration matrix:
  • path, method, auth, throttle, input DTO, output DTO,
  • expected statuses, expected headers,
  • known error paths.

Inventory project-native batteries (required)

• Before writing adapters, inspect existing project libraries and integrations that should power the migrated transport layer.
• Prefer libraries already used by the project ("Django batteries") through DMR mechanisms over custom wrappers.
• Examples:
  • rate limiting: prefer django-ratelimit integration when it exists, instead of wrapping Ninja throttles,
  • auth/account lockout: prefer existing project auth stack (e.g. axes/middleware) instead of reusing Ninja-specific auth internals.

Freeze observable behavior

• Capture behavior from existing tests + DTOs + routing.
• Mark blocking mismatches before coding:
  • route/method changes,
  • schema field changes,
  • auth/throttle changes,
  • status/header changes.

Decide error strategy (required gate)

Choose one and record it before edits:

• strict parity:
  • keep existing error status/payload semantics,
  • adapt DMR handlers/context as needed.
• approved DMR-native errors:
  • use framework-native error mapping,
  • update tests and docs expectations accordingly,
  • still preserve happy-path behavior and auth/throttle behavior.

Migrate by slice (app or endpoint group)

• Migrate one bounded slice at a time.
• Keep module layout unless architecture/lint contracts require change.
• Do not keep class names that encode Ninja infrastructure. Rename transport classes to neutral or DMR-oriented names.
• Prefer thin transport adapters:
  • keep usecases/services/repositories untouched,
  • change only DTOs/controllers/router wiring.

Translate DTOs and components

• Replace ninja.Schema with explicit typed DTOs compatible with DMR serializer.
• Map request sources explicitly:
  • body Body[...], query Query[...], path Path[...], headers Headers[...], cookies Cookies[...].
• Split input/output DTOs when response contains server-owned fields.

Translate handlers to DMR

• Single operation: Controller[...].
• Multi-method path: controllers + composition.
• Keep route names and URL shapes stable unless user requested drift.
• Port exception behavior intentionally:
  • strict parity mode: preserve old statuses/payloads,
  • approved drift mode: keep DMR-native errors and update tests.

Replace API wiring

• Replace NinjaExtraAPI with DMR router + Django URL include wiring.
• Keep namespace stability (api:* names) unless drift approved.
• Add docs/openapi routes only if project already exposes them.

Port auth and throttling with native batteries

• Keep auth expectations endpoint-by-endpoint.
• Keep throttling behavior and headers (e.g. Retry-After) unless drift approved.
• Prefer existing project-native auth/throttle libraries through DMR hooks.
• Always enable global validate_responses settings in local development and testing.
• Ensure all extra responses are explicitly declared with ResponseSpec.
• Require all responses to pass response validation.
• Avoid Ninja compatibility shims as final solution. If a temporary shim is unavoidable, mark it explicitly as temporary, document replacement plan, and list it in unresolved gaps.

Update tests for DMR tooling

• Replace Ninja-specific test tooling (ninja.testing.TestClient, NinjaExtra helpers, Ninja URL setup fixtures) with repository-native Django/DMR testing entrypoints.
• Migrate API test fixtures and clients as first-class migration scope: keep fixture intent stable (api_client, authed_api_client, token/auth fixtures), but rebind them to the migrated DMR stack.
• Audit and update pytest plugin wiring (conftest.py / plugin modules) so migrated API tests no longer depend on Ninja-only fixtures or helpers.
• Keep contract assertions endpoint-by-endpoint: status codes, payloads, headers, auth behavior, throttle behavior.
• Ensure negative-path tests cover declared extra responses and match ResponseSpec metadata.
• Remove persistent django-ninja / ninja-extra imports from migrated test modules unless explicitly approved as temporary drift.

Validate each slice with repository-native CI entrypoints

• Run the same commands CI uses in this repository.
• Prefer official script entrypoints over ad-hoc command sets.
• If docker-only CI/test environment is required, run in docker.

Finish gate

Do not mark slice done until:

• linters pass,
• tests pass (or failures are explicitly approved drift),
• report is updated.

Translation Rules

• Business logic unchanged by default.
• Keep transport deterministic and typed.
• Avoid hidden route normalization changes (trailing slash/prefix).
• Preserve auth and throttle semantics even when error payload format drifts.
• Be explicit about framework constraints (for example DMR-native validation behavior).
• Do not use django-ninja / ninja-extra classes in migrated slices unless explicitly approved by the user as temporary.
• Do not keep Ninja-bound class names (for example names prefixed with Ninja...) in migrated transport code.

Reporting Format (required)

At each meaningful checkpoint and at completion, report in 3 sections:

1. preserved behavior
2. approved drift
3. unresolved gaps

unresolved gaps must include concrete files/endpoints and why unresolved.

Migration Pitfalls (repo-derived)

• django-ratelimit integration: do not pass method='ALL' as a string. Use ratelimit.core.ALL (or equivalent tuple) or rate-limiting silently won't trigger.
• If base Pydantic config uses strict=True, JSON UUID strings can fail validation (Input should be an instance of UUID). For request DTO fields that accept UUID from JSON, allow parsing explicitly (for example field-level strict=False).
• If preserving strict input schema (unknown fields must fail), do not rely on a base model with extra='ignore' for input DTOs. Set input DTO config to reject extra fields (for example extra='forbid').
• In approved DMR-native errors mode, DB integrity failures may surface as unhandled 500 if not mapped. Use DMR endpoint/controller error handling (modify(error_handler=...) or controller-level handler) to keep predictable client error behavior without reviving legacy Ninja payload shape.
• CI hygiene: avoid debug commands that create project-local tooling artifacts (for example .local/... from ad-hoc virtualenv/poetry runs), as format/lint stages may scan and fail on them.

Output Checklist

• Ninja root wiring replaced with DMR routing.
• Ninja controllers/handlers replaced with DMR controllers.
• ninja.Schema DTOs replaced for migrated endpoints.
• Auth/throttle behavior preserved or explicitly drift-approved.
• Project-native batteries were evaluated first and used where possible.
• No persistent Ninja shim or Ninja-bound naming remains in migrated transport layer.
• Tests updated only where needed to keep equivalent behavioral coverage for selected strategy.
• Response validation is enabled and all migrated endpoint responses pass it (including extra responses declared via ResponseSpec).
• Repository-native CI entrypoints executed per slice.
• Final report emitted in required 3-section format.
• After successful migration and green CI for migrated API surfaces, remove 'django-ninja' and 'ninja-extra' from project dependencies unless user explicitly approves keeping them.