feat(init): initial commit for Flask-based temporary file transfer service (web UI, API, SQLite)

database.py

@@ -0,0 +1,61 @@
+import sqlite3
+import os
+from datetime import datetime, timedelta
+from config import DATABASE
+
+def get_db():
+    conn = sqlite3.connect(DATABASE)
+    conn.row_factory = sqlite3.Row
+    return conn
+
+def init_db():
+    os.makedirs(os.path.dirname(DATABASE) if os.path.dirname(DATABASE) else '.', exist_ok=True)
+    conn = get_db()
+    conn.execute('''
+        CREATE TABLE IF NOT EXISTS files (
+            id TEXT PRIMARY KEY,
+            filename TEXT NOT NULL,
+            filepath TEXT NOT NULL,
+            filesize INTEGER NOT NULL,
+            expiry_hours INTEGER NOT NULL,
+            created_at TIMESTAMP NOT NULL,
+            expires_at TIMESTAMP NOT NULL
+        )
+    ''')
+    conn.commit()
+    conn.close()
+
+def add_file(file_id, filename, filepath, filesize, expiry_hours):
+    now = datetime.utcnow()
+    expires = now + timedelta(hours=expiry_hours)
+    conn = get_db()
+    conn.execute(
+        'INSERT INTO files (id, filename, filepath, filesize, expiry_hours, created_at, expires_at) VALUES (?, ?, ?, ?, ?, ?, ?)',
+        (file_id, filename, filepath, filesize, expiry_hours, now, expires)
+    )
+    conn.commit()
+    conn.close()
+
+def get_file(file_id):
+    conn = get_db()
+    row = conn.execute('SELECT * FROM files WHERE id = ?', (file_id,)).fetchone()
+    conn.close()
+    return row
+
+def delete_file(file_id):
+    conn = get_db()
+    conn.execute('DELETE FROM files WHERE id = ?', (file_id,))
+    conn.commit()
+    conn.close()
+
+def cleanup_expired():
+    now = datetime.utcnow()
+    conn = get_db()
+    expired = conn.execute('SELECT * FROM files WHERE expires_at < ?', (now,)).fetchall()
+    for row in expired:
+        if os.path.exists(row['filepath']):
+            os.remove(row['filepath'])
+    conn.execute('DELETE FROM files WHERE expires_at < ?', (now,))
+    conn.commit()
+    conn.close()
+    return len(expired)