bumped up version to 0.0.6

## Summary

Resolve `{ENV_VAR}` placeholders in the OpenAPI spec before serving it. Replace the monolithic `x-introspect-url` extension with composable `x-server-url` + individual `x-*-path` fields so auth endpoints are configurable per-environment without hardcoding.

## Changes

- **`openapi_first/app.py`** — add `_resolve_spec_env_vars()` that replaces `{ENV_VAR}` patterns (e.g. `{AUTH_SERVER}`) with the corresponding OS environment variable before returning the spec JSON. Called in `__init__` after spec load.
- **`openapi_first/security.py`** — build the introspection URL dynamically from `x-server-url` + `x-introspect-path` extensions on the `bearerAuth` security scheme, instead of reading a single `x-introspect-url`.

## Migration

Existing specs using `x-introspect-url: "https://auth.example.com/introspect"` must switch to the new extension format:

```yaml
components:
  securitySchemes:
    bearerAuth:
      type: http
      scheme: bearer
      x-server-url: "{AUTH_SERVER}"
      x-login-path: "/login"
      x-register-path: "/register"
      x-logout-path: "/logout"
      x-me-path: "/me"
      x-introspect-path: "/introspect"

Reviewed-on: #3
Co-authored-by: Vishesh 'ironeagle' Bangotra <aetoskia@gmail.com>
Co-committed-by: Vishesh 'ironeagle' Bangotra <aetoskia@gmail.com>

openapi_first/__init__.py

@@ -102,6 +102,7 @@ from . import client
 from . import errors
 from . import codegen
 from . import codegen_routes
+from . import security
 
 __all__ = [
     "app",
@@ -111,4 +112,5 @@ __all__ = [
     "errors",
     "codegen",
     "codegen_routes",
+    "security",
 ]

openapi_first/app.py

@@ -32,10 +32,34 @@ Notes:
             - Alter FastAPI dependency injection semantics.
 """
 
+import os
+import re
+
 from fastapi import FastAPI
 
-from .loader import load_openapi
 from .binder import bind_routes
+from .loader import load_openapi
+from .security import make_security_dependencies, parse_security_schemes
+
+_env_pattern = re.compile(r"\{(\w+)\}")
+
+
+def _resolve_env(value: str) -> str:
+    """Replace {ENV_VAR} placeholders with values from os.environ."""
+    def _replace(m: re.Match) -> str:
+        return os.environ.get(m.group(1), m.group(0))
+    return _env_pattern.sub(_replace, value)
+
+
+def _resolve_spec_env_vars(obj):
+    """Recursively resolve {ENV_VAR} in all string values of the spec."""
+    if isinstance(obj, str):
+        return _resolve_env(obj)
+    if isinstance(obj, dict):
+        return {k: _resolve_spec_env_vars(v) for k, v in obj.items()}
+    if isinstance(obj, list):
+        return [_resolve_spec_env_vars(v) for v in obj]
+    return obj
 
 
 class OpenAPIFirstApp(FastAPI):
@@ -48,15 +72,19 @@ class OpenAPIFirstApp(FastAPI):
             - `OpenAPIFirstApp` subclasses `FastAPI` and replaces manual route
               registration with OpenAPI-driven binding.
             - All routes are derived from the provided OpenAPI specification,
-              and each `operationId` is mapped to a Python function in the
+              and each ``operationId`` is mapped to a Python function in the
               supplied routes module.
+            - Auth dependencies are auto-injected from the spec's
+              ``securitySchemes`` and per-operation ``security`` fields.
 
         **Guarantees:**
 
             - No route can exist without an OpenAPI declaration.
             - No OpenAPI operation can exist without a handler.
-            - Swagger UI and `/openapi.json` always reflect the provided spec.
+            - Swagger UI and ``/openapi.json`` always reflect the provided spec.
             - Handler functions remain framework-agnostic and testable.
+            - Auth enforcement is driven entirely by the spec — no manual
+              middleware or decorators required.
 
     Example:
         ```python
@@ -87,28 +115,33 @@ class OpenAPIFirstApp(FastAPI):
                 specification is treated as the authoritative API contract.
             routes_module (module):
                 Python module containing handler functions whose names correspond
-                exactly to OpenAPI `operationId` values.
+                exactly to OpenAPI ``operationId`` values.
             **fastapi_kwargs (Any):
                 Additional keyword arguments passed directly to
-                `fastapi.FastAPI` (e.g., title, version, middleware, lifespan
+                ``fastapi.FastAPI`` (e.g., title, version, middleware, lifespan
                 handlers).
 
         Raises:
             OpenAPIFirstError:
                 If the OpenAPI specification is invalid, or if any declared
-                `operationId` does not have a corresponding handler function.
+                ``operationId`` does not have a corresponding handler function.
         """
         # Initialize FastAPI normally
         super().__init__(**fastapi_kwargs)
 
         # Load and validate OpenAPI specification
-        self._openapi_spec = load_openapi(openapi_path)
+        self._openapi_spec = _resolve_spec_env_vars(load_openapi(openapi_path))
 
-        # Bind routes strictly from OpenAPI spec
+        # Parse security schemes and build per-route dependencies
+        security_schemes = parse_security_schemes(self._openapi_spec)
+        security_deps = make_security_dependencies(self._openapi_spec, security_schemes)
+
+        # Bind routes strictly from OpenAPI spec (with security deps)
         bind_routes(
             app=self,
             spec=self._openapi_spec,
             routes_module=routes_module,
+            security_deps=security_deps,
         )
 
         # Override FastAPI's OpenAPI generation

openapi_first/binder.py

@@ -32,12 +32,19 @@ Notes:
             - Interpret OpenAPI semantics beyond routing metadata.
 """
 
+from typing import Any
+
 from fastapi.routing import APIRoute
 
 from .errors import MissingOperationHandler
 
 
-def bind_routes(app, spec: dict, routes_module) -> None:
+def bind_routes(
+    app,
+    spec: dict,
+    routes_module,
+    security_deps: dict[str, list[Any]] | None = None,
+) -> None:
     """
     Bind OpenAPI operations to FastAPI routes.
 
@@ -49,18 +56,24 @@ def bind_routes(app, spec: dict, routes_module) -> None:
         routes_module (module):
             Python module containing handler functions. Each handler's name MUST
             exactly match an OpenAPI `operationId`.
+        security_deps (dict | None):
+            Optional mapping of ``METHOD:/path`` → ``list[Depends(...)]``
+            generated from the spec's ``securitySchemes`` and per-operation
+            ``security`` fields.
 
     Raises:
         MissingOperationHandler:
-            If an `operationId` is missing from the spec or if no corresponding
+            If an ``operationId`` is missing from the spec or if no corresponding
             handler function exists in the routes module.
 
     Notes:
         **Responsibilities:**
 
             - Iterates through the OpenAPI specification paths and methods.
-            - Resolves each `operationId` to a handler function, and registers
+            - Resolves each ``operationId`` to a handler function, and registers
-              a corresponding `APIRoute` on the FastAPI application.
+              a corresponding ``APIRoute`` on the FastAPI application.
+            - Injects FastAPI ``Depends()`` for each security requirement found
+              on the operation or inherited from the top-level ``security`` field.
 
         **Guarantees:**
 
@@ -70,6 +83,7 @@ def bind_routes(app, spec: dict, routes_module) -> None:
     """
 
     paths = spec.get("paths", {})
+    security_deps = security_deps or {}
 
     for path, methods in paths.items():
         for http_method, operation in methods.items():
@@ -90,10 +104,14 @@ def bind_routes(app, spec: dict, routes_module) -> None:
                     operation_id=operation_id,
                 )
 
+            key = f"{http_method.upper()}:{path}"
+            deps = security_deps.get(key, [])
+
             route = APIRoute(
                 path=path,
                 endpoint=endpoint,
                 methods=[http_method.upper()],
+                dependencies=deps,
                 name=operation_id,
             )
 

openapi_first/security.py

@@ -0,0 +1,145 @@
+"""
+OpenAPI security scheme parsing and auto-generated auth dependencies.
+
+Reads `securitySchemes` and per-operation `security` from an OpenAPI spec,
+resolves `{ENV_VAR}` placeholders in `x-` extension fields, and generates
+FastAPI dependencies for token validation (e.g., Bearer JWT introspection).
+"""
+
+import os
+import re
+from typing import Any, Callable
+
+import httpx
+from fastapi import Depends, Request, HTTPException
+from fastapi.security import HTTPAuthorizationCredentials, HTTPBearer
+
+_env_pattern = re.compile(r"\{(\w+)\}")
+
+
+def _resolve_env(value: str) -> str:
+    """Replace {ENV_VAR} placeholders with values from os.environ."""
+    def _replace(m: re.Match) -> str:
+        return os.environ.get(m.group(1), "")
+    return _env_pattern.sub(_replace, value)
+
+
+def _resolve_scheme(scheme: dict) -> dict:
+    """Recursively resolve env vars in all string-valued fields of a scheme."""
+    resolved = {}
+    for key, value in scheme.items():
+        if isinstance(value, str):
+            resolved[key] = _resolve_env(value)
+        elif isinstance(value, dict):
+            resolved[key] = _resolve_scheme(value)
+        else:
+            resolved[key] = value
+    return resolved
+
+
+def parse_security_schemes(spec: dict) -> dict[str, dict]:
+    """Extract and resolve environment variables in security schemes."""
+    raw = spec.get("components", {}).get("securitySchemes", {})
+    return {name: _resolve_scheme(scheme) for name, scheme in raw.items()}
+
+
+def _make_bearer_dependency(introspect_url: str | None) -> Callable:
+    """
+    Create a FastAPI dependency that validates a Bearer JWT.
+
+    If *introspect_url* is provided the dependency calls that endpoint
+    with ``{"token": "<token>"}`` and expects ``{"active": true, "user": …}``
+    back.  The resolved user dict is stored on ``request.state.user``.
+
+    Without an introspection URL the dependency only extracts the raw token
+    and stores it on ``request.state.token`` — no remote validation.
+    """
+    bearer = HTTPBearer(auto_error=False)
+
+    async def _bearer_dep(
+        request: Request,
+        credentials: HTTPAuthorizationCredentials | None = Depends(bearer),
+    ) -> None:
+        if credentials is None:
+            raise HTTPException(status_code=401, detail="Not authenticated")
+
+        token = credentials.credentials
+
+        if introspect_url:
+            try:
+                async with httpx.AsyncClient(timeout=5) as client:
+                    resp = await client.post(
+                        introspect_url,
+                        json={"token": token},
+                    )
+            except httpx.RequestError:
+                raise HTTPException(
+                    status_code=503,
+                    detail="Authentication service unavailable",
+                )
+
+            if resp.status_code != 200:
+                raise HTTPException(status_code=401, detail="Invalid or expired token")
+
+            body = resp.json()
+            if not body.get("active", False):
+                raise HTTPException(status_code=401, detail="Invalid or expired token")
+
+            request.state.user = body.get("user")
+        else:
+            request.state.token = token
+
+    return _bearer_dep
+
+
+def _build_dependency(scheme_name: str, scheme: dict) -> Callable | None:
+    """Return a FastAPI dependency callable for *scheme*, or ``None``."""
+    scheme_type = scheme.get("type")
+
+    if scheme_type == "http" and scheme.get("scheme") == "bearer":
+        server_url = scheme.get("x-server-url", "")
+        introspect_path = scheme.get("x-introspect-path", "/introspect")
+        introspect_url = server_url + introspect_path if server_url else None
+        return _make_bearer_dependency(introspect_url)
+
+    return None
+
+
+def make_security_dependencies(
+    spec: dict,
+    security_schemes: dict[str, dict],
+) -> dict[str, list[Any]]:
+    """
+    Build a mapping of ``METHOD:/path`` → list of ``Depends(...)``.
+
+    The effective security for each operation is resolved by:
+
+    1. Using the operation-level ``security`` field if present.
+    2. Falling back to the top-level ``security`` field.
+    3. An empty list means *no auth required* for that operation.
+    """
+    global_security = spec.get("security", [])
+    paths = spec.get("paths", {})
+
+    result: dict[str, list[Any]] = {}
+
+    for path, methods in paths.items():
+        for http_method, operation in methods.items():
+            if http_method.startswith("x-"):
+                continue
+
+            op_security = operation.get("security", global_security)
+
+            depends_list: list[Any] = []
+            for sec_req in op_security:
+                for scheme_name in sec_req:
+                    scheme = security_schemes.get(scheme_name)
+                    if scheme:
+                        dep = _build_dependency(scheme_name, scheme)
+                        if dep:
+                            depends_list.append(Depends(dep))
+
+            key = f"{http_method.upper()}:{path}"
+            result[key] = depends_list
+
+    return result

pyproject.toml

@@ -5,7 +5,7 @@ build-backend = "setuptools.build_meta"
 
 [project]
 name = "openapi-first"
-version = "0.0.4"
+version = "0.0.6"
 description = "Strict OpenAPI-first application bootstrap for FastAPI."
 readme = "README.md"
 requires-python = ">=3.10"
@@ -55,6 +55,9 @@ dependencies = [
 
     # Code generation
     "datamodel-code-generator>=0.25.0",
+
+    # HTTP client for service-to-service (token introspection)
+    "httpx>=0.27.0",
 ]
 
 [project.scripts]