add: accept and extract zip photo archives

main.py

@@ -1,4 +1,4 @@
-from fastapi import FastAPI, File, UploadFile, Depends
+from fastapi import FastAPI, File, UploadFile, Depends, BackgroundTasks
 from fastapi.responses import JSONResponse
 from fastapi.security import HTTPBasic, HTTPBasicCredentials
 from fastapi.middleware.cors import CORSMiddleware  # CORS
@@ -7,12 +7,14 @@ from secrets import compare_digest
 from datetime import datetime
 from uuid import uuid4
 import sqlite3
+import zipfile
 
 
 # use database residing here
 DB_LOCATION = (
     "../testbox/photovoter.dblite"  # Q: any allowances for this being not OUR database?
 )
+DATA_LOCATION = "/tmp/123"
 
 app = FastAPI()
 security = HTTPBasic()
@@ -178,24 +180,66 @@ async def photo_points():
 @app.post(
     "/upload_pictures/",
     responses={
+        202: {"description": "Archive accepted into processing"},
         401: {"description": "Authentication is required to access this resource"},
         415: {"description": "Cannot process uploaded archive"},
     },
 )
 async def upload_pictures(
-    credentials: HTTPBasicCredentials = Depends(security), file: UploadFile = File(...)
+    background_tasks: BackgroundTasks,
+    credentials: HTTPBasicCredentials = Depends(security),
+    file: UploadFile = File(...),
 ):
     """Интерфейс для загрузки фотографий"""
     """Условно кладём в браузер zip с фотографиями и он их потихоньку ест. 
     Доступ к этому интерфейсу, наверное, лучше ограничить паролем или как-нибудь ещё.
-    Пока исходим из предположения, что только я буду загружать фотографии."""
+    Пока исходим из предположения, что только я буду загружать фотографии.
+    """
     # check authenticity
     correct_username = compare_digest(credentials.username, "1")
     correct_password = compare_digest(credentials.password, "1")
     if not (correct_username and correct_password):
         return JSONResponse(status_code=401)
     # slurp the zip
-    # *detach from the interface, if possible
+    if not zipfile.is_zipfile(file.file):
+        return JSONResponse(status_code=415)
+    # detach from the interface
     # unpack zip
+    tasks = BackgroundTasks()
+    tasks.add_task(
+        unpack_pictures_zip,
+        file=file,
+        time=datetime.utcnow().replace(microsecond=0).isoformat(),
+    )
+
     # feed the pictures to util/import_photos.py
-    return {"filename": file.filename}
+    return JSONResponse("Accepted", background=tasks)
+
+
+def unpack_pictures_zip(file: UploadFile, time):
+    """
+    Unpack and process zip archived photo
+    Extract pictures in the DATA_LOCATION/processing 
+    #TODO: and feed them to util/import_photos.py
+    #TODO: Walk the nested DATA_LOCATION/processing ourselves 
+    Uses: DATA_LOCATION
+    """
+    # we only call this function sporadically, so import here
+    import os
+
+    print(f"Accepted {file.filename} at {time} into processing")
+    os.chdir(DATA_LOCATION)
+    os.mkdir("processing")
+    os.chdir("processing")
+
+    # using private ._file field is a dirty hack, but
+    # SpooledTemporaryFile does not implement seekable
+    # required by zipfile 'r' mode
+    # https://bugs.python.org/issue26175
+    with zipfile.ZipFile(file.file._file) as photo_zip:
+        problem_files = photo_zip.testzip()
+        if problem_files is not None:
+            print(f"Errors in {file.filename} accepted at {time}: {problem_files}")
+        photo_zip.extractall()
+        photo_zip.close()
+    print(f"Succesfully processed {file.filename} accepted at {time}")