added .env + delete file + handle error when file didns saved but added to db

app/db.py

@@ -4,9 +4,13 @@ from sqlalchemy import create_engine
 from sqlalchemy.orm import Session, sessionmaker
 from sqlalchemy import select
 
-PADDING = 5
+from dotenv import load_dotenv
+import os 
+load_dotenv()
+PADDING = int(os.getenv("FILES_PADDING"))
+DATABASE_NAME = os.getenv("DATABASE_NAME")
 
-engine = create_engine("sqlite:///example.db")
+engine = create_engine(f"sqlite:///{DATABASE_NAME}.db")
 session = Session(bind=engine)
 
 class Base(DeclarativeBase): pass
@@ -38,6 +42,22 @@ def to_base36(n: int, width: int) -> str:
         result.append(chars[rem])
     return "".join(reversed(result)).rjust(width, "0")
 
+
+def from_base36(s: str) -> int:
+    chars = "0123456789abcdefghijklmnopqrstuvwxyz"
+    char_to_val = {c: i for i, c in enumerate(chars)}
+
+    s = s.lower().lstrip("0")
+    if not s:  
+        return 0
+
+    n = 0
+    for ch in s:
+        if ch not in char_to_val:
+            raise ValueError(f"Invalid base36 character: {ch}")
+        n = n * 36 + char_to_val[ch]
+    return n
+
 Base.metadata.create_all(bind=engine)
 
 def get_all_files():
@@ -83,6 +103,17 @@ def add_file(filename: str, content_type, size: int, hash):
 
         return url
 
+
+def remove_file(file_url: str):
+    with Session(autoflush=False, bind=engine) as db:
+        file_id = from_base36(file_url.rsplit(".")[0])
+        file = db.get(File, file_id)
+        if not file:
+            return None
+        db.delete(file)
+        db.commit() 
+        return True
+
 if __name__ == "__main__":
     for i in get_all_files():
         print(f"{i.id} {i.name}.{i.extension} ({i.hash}) {i.content_type} {i.size}")