Add fastapi_vue.env accessor with FASTAPI_VUE prefix

fastapi-vue/README.md

@@ -68,3 +68,13 @@ server.run("my_app.app:app", listen=["localhost:8000"])
 ```
 
 - As a deployment option, environment `FORWARDED_ALLOW_IPS` controls `X-Forwarded` trusted IPs (default: `127.0.0.1,::1`).
+
+## Environment variables
+
+The generated project entry point sets `FASTAPI_VUE` to the project's environment prefix (e.g. `MY_APP`), and settings are passed as `<PREFIX>_*` variables. `fastapi_vue.env` resolves them, lazily on each access:
+
+- `fastapi_vue.env.dev` — running under the devserver (`<PREFIX>_DEV=1`)
+- `fastapi_vue.env.vite_url`, `fastapi_vue.env.backend_url` — URLs set by the devserver
+- `fastapi_vue.env.prefix` — the prefix itself
+
+Value accessors return `None` when `FASTAPI_VUE` or the variable is not set.

fastapi-vue/fastapi_vue/__init__.py

@@ -1,5 +1,6 @@
 """FastAPI Vue integration - serve Vue frontend from FastAPI."""
 
+from .environ import env
 from .staticfiles import Frontend
 
-__all__ = ["Frontend"]
+__all__ = ["Frontend", "env"]

fastapi-vue/fastapi_vue/environ.py

@@ -0,0 +1,46 @@
+"""Access to the project's fastapi-vue environment variables.
+
+The project entry point (generated __main__.py) sets FASTAPI_VUE to the
+project-specific prefix (e.g. "MY_APP"). Project settings are then passed
+as "<PREFIX>_*" environment variables; this module is the single place
+that resolves those names.
+"""
+
+import os
+
+PREFIX_VARIABLE = "FASTAPI_VUE"
+
+
+class _Env:
+    """Lazy accessors for the project's "<PREFIX>_*" environment variables.
+
+    Evaluated on each access. Value accessors return None when FASTAPI_VUE
+    or the variable itself is not set.
+    """
+
+    @property
+    def prefix(self) -> str | None:
+        """Return the project prefix from the FASTAPI_VUE environment variable."""
+        return os.environ.get(PREFIX_VARIABLE) or None
+
+    def _get(self, name: str) -> str | None:
+        prefix = self.prefix
+        return os.environ.get(f"{prefix}_{name}") if prefix else None
+
+    @property
+    def dev(self) -> bool:
+        """Check whether running under the devserver (<PREFIX>_DEV=1)."""
+        return self._get("DEV") == "1"
+
+    @property
+    def vite_url(self) -> str | None:
+        """Return the vite devserver URL (<PREFIX>_VITE_URL), if set."""
+        return self._get("VITE_URL")
+
+    @property
+    def backend_url(self) -> str | None:
+        """Return the backend URL (<PREFIX>_BACKEND_URL), if set."""
+        return self._get("BACKEND_URL")
+
+
+env = _Env()

fastapi-vue/fastapi_vue/server.py

@@ -15,6 +15,7 @@ from uvicorn import Config, Server
 from uvicorn.main import STARTUP_FAILURE
 from uvicorn.supervisors import ChangeReload, Multiprocess
 
+from .environ import env
 from .hostutil import parse_endpoints
 from .logging import (
     install_access_log,
@@ -44,10 +45,16 @@ def _bind_hosts(host: str) -> list[str]:
 
 
 def _connect_url(endpoints: list[dict]) -> str:
-    """Return a URL the user can connect to for the first TCP endpoint."""
-    for key, value in sorted(os.environ.items()):
-        if key.endswith("_VITE_URL") and value:
-            return value
+    """Return a URL the user can connect to for the first TCP endpoint.
+
+    When running under the devserver (<PREFIX>_VITE_URL is set), the vite
+    devserver URL is shown instead, as that is where the page is served.
+    Wildcard binds (0.0.0.0, ::) are shown as localhost, as that is the
+    address a user can actually open. Unix-socket-only setups show plain
+    http://localhost (the typical reverse-proxy target).
+    """
+    if vite_url := env.vite_url:
+        return vite_url
     for endpoint in endpoints:
         host = endpoint.get("host")
         if host is None:

fastapi-vue/fastapi_vue/staticfiles.py

@@ -19,6 +19,8 @@ from starlette.exceptions import HTTPException
 from starlette.routing import Route
 from zstandard import ZstdCompressor
 
+from .environ import env
+
 logger = logging.getLogger("uvicorn.error")  # Use FastAPI logging style
 
 __all__ = ["Frontend"]
@@ -287,7 +289,8 @@ class Frontend:
 
 def _devmode_respond(_request: Request, _name: str = "") -> JSONResponse:
     """Return error response directing to Vite server."""
+    at = f" at {env.vite_url}" if env.vite_url else ""
     return JSONResponse(
         status_code=409,
-        content={"detail": "[devmode] Use Vite devserver instead."},
+        content={"detail": f"[devmode] Use Vite devserver{at} instead."},
     )