US05-01: Validate Credentials and Upload Readiness

photo_pipeline/api/app.py

@@ -25,6 +25,7 @@ from photo_pipeline.api.routes import (
     renames,
     safety,
     thumbnails,
+    uploads,
     workflow,
 )
 
@@ -67,6 +68,7 @@ def create_app(config: Config | None = None) -> FastAPI:
     app.include_router(library.router, prefix="/api/v1")
     app.include_router(albums.router, prefix="/api/v1")
     app.include_router(renames.router, prefix="/api/v1")
+    app.include_router(uploads.router, prefix="/api/v1")
     # Static single-page app (hash-routed). Mounted last so /api/v1 wins.
     if FRONTEND_DIR.is_dir():
         app.mount("/app", StaticFiles(directory=FRONTEND_DIR, html=True), name="app")

photo_pipeline/api/routes/uploads.py

@@ -0,0 +1,39 @@
+"""Upload preflight API (US05-01).
+
+Preflight is a command, not a resource read: it contacts the Immich server, hashes
+the current bytes, and issues a token. It uploads nothing — starting a batch is
+US05-02, so there is deliberately no start endpoint here.
+"""
+
+from __future__ import annotations
+
+from fastapi import APIRouter, Request
+from fastapi.responses import JSONResponse
+from pydantic import BaseModel
+
+from photo_pipeline.services.uploads import UploadError, UploadService
+
+router = APIRouter(tags=["uploads"])
+
+
+class PreflightRequest(BaseModel):
+    # ``None`` means every album; an explicit list scopes the check.
+    albums: list[str] | None = None
+    # Approving a partial upload is an explicit act, never a default.
+    allow_partial: bool = False
+
+
+def _service(request: Request) -> UploadService:
+    return UploadService(request.app.state.session_factory, config=request.app.state.config)
+
+
+@router.post("/upload-preflight")
+def preflight(request: Request, body: PreflightRequest | None = None):
+    body = body or PreflightRequest()
+    try:
+        return _service(request).preflight(body.albums, allow_partial=body.allow_partial)
+    except UploadError as error:
+        return JSONResponse(
+            status_code=422,
+            content={"error": {"code": "unknown_album", "message": str(error)}},
+        )