Refactored getmail.py into functions

getmail.py

@@ -47,7 +47,8 @@ from datetime import datetime
 from dotenv import load_dotenv
 from imap_tools import MailBox, AND
 
-# Initialise logging
+def setup_logging():
+    """Initialize logging configuration."""
     logging.basicConfig(
         level=logging.DEBUG,
         format='%(asctime)s %(levelname)s %(message)s',
@@ -55,13 +56,12 @@ logging.basicConfig(
         filemode='a')
     logging.debug('%a started in %s', 'getmail.py', os.getcwd())
 
-# Load our environment vars from our .env file
+def load_environment_variables():
-# This is just keys and values - eg MBOX_USER = 'test@someemail.com'
+    """Load environment variables from .env file."""
-# One key/value pair per line
     dotenv_path = join(dirname(__file__), ".env")
     try:
         with open(dotenv_path, 'r', encoding='utf-8') as env:
-        pass
+            logging.debug('success opening env file: %a', env)
         load_dotenv(dotenv_path)
     except FileNotFoundError:
         logging.error('config file %a is missing - unable to proceed', dotenv_path)
@@ -70,73 +70,86 @@ except Exception as e:
         logging.error('An unexpected error occurred: %s', str(e))
         sys.exit(1)
 
-# Function to compute the hash of an attachment to determine uniqueness
 def compute_hash(content):
-    """Function to generate a simple file hash. Could be more secure."""
+    """Generate a simple file hash to determine uniqueness."""
     return hashlib.sha256(content).hexdigest()
 
-# File to store hashes of saved attachments
+def load_saved_hashes(hashes_file):
-HASHES_FILE = 'saved_hashes.json'
+    """Load saved hashes from the file."""
+    if os.path.exists(hashes_file):
+        with open(hashes_file, 'r', encoding='utf-8') as f:
+            return set(json.load(f))
+    return set()
 
-# Load saved hashes from the file
+def save_hashes(hashes_file, hashes):
-if os.path.exists(HASHES_FILE):
+    """Save updated hashes to the file."""
-    with open(HASHES_FILE, 'r', encoding='utf-8') as f:
+    with open(hashes_file, 'w', encoding='utf-8') as f:
-        saved_hashes = set(json.load(f))
+        json.dump(list(hashes), f)
-else:
-    saved_hashes = set()
 
-# Set our constants from the environment
+def setup_ssl_context():
-USERNAME = os.environ.get("MBOX_USER")
+    """Set up the SSL context."""
-PASSWORD = os.environ.get("MBOX_PASS")
-DEFAULT_FOLDER = os.environ.get("MBOX_FOLDER", "Inbox")
-PORT = 993
-
-if not USERNAME or not PASSWORD:
-    logging.error('Missing mailbox username or password in environment')
-    sys.exit(1)
-
-# Other constants
-ATTACHMENT_PATH = join(dirname(__file__), "attachments")
-HOST = "helpdesk.sense7.co.nz"
-
-if not os.path.exists(ATTACHMENT_PATH):
-    os.makedirs(ATTACHMENT_PATH)
-
-# Set SSL context for "secure" (self-signed cert etc.) connection
     ssl_context = ssl.create_default_context()
     ssl_context.minimum_version = ssl.TLSVersion.TLSv1_3
     ssl_context.maximum_version = ssl.TLSVersion.TLSv1_3
     ssl_context.load_cert_chain(certfile="./one.crt", keyfile="./one.key")
+    return ssl_context
 
-# Process mailbox
+def process_attachments(mailbox, attachment_path, saved_hashes):
-with MailBox(HOST, port=PORT, ssl_context=ssl_context).login(
+    """Process and save email attachments."""
-        USERNAME, PASSWORD, DEFAULT_FOLDER) as mailbox:
-
     for msg in mailbox.fetch(AND(seen=False), mark_seen=False):
         for att in msg.attachments:
-            ATTACHMENT_HASH = compute_hash(att.payload)
+            attachment_hash = compute_hash(att.payload)
 
-            if ATTACHMENT_HASH not in saved_hashes:
+            if attachment_hash not in saved_hashes:
                 filename, file_ext = os.path.splitext(att.filename)
+                logging.debug('found new attachment named %a', filename)
                 current_datetime = datetime.now().strftime("%Y-%m-%d_%H-%M-%S")
-                FINAL_NAME = (
+                final_name = (
                     f"{current_datetime}_"
-                    f"{ATTACHMENT_HASH[:8]}"
+                    f"{attachment_hash[:8]}"
                     f"{file_ext}"
                 )
 
-                with tempfile.NamedTemporaryFile(
+                with tempfile.NamedTemporaryFile(delete=False, dir="temp") as temp_file:
-                    delete=False, dir="temp") as temp_file:
                     temp_file.write(att.payload)
                     temp_path = temp_file.name
-                    final_path = os.path.join(ATTACHMENT_PATH, FINAL_NAME)
+                    final_path = os.path.join(attachment_path, final_name)
                     os.rename(temp_path, final_path)  # Atomic move
                     logging.info("Saved attachment as: %s", final_path)
-                    saved_hashes.add(ATTACHMENT_HASH)
+                    saved_hashes.add(attachment_hash)
             else:
                 logging.info("Skipped duplicate attachment: %s", att.filename)
         mailbox.flag(msg.uid, '\\Seen', True)
 
-# Save the updated hashes to the file
+def main():
-with open(HASHES_FILE, 'w', encoding='utf-8') as f:
+    """Code entrypoint."""
-    json.dump(list(saved_hashes), f)
+    setup_logging()
+    load_environment_variables()
+
+    hashes_file = 'saved_hashes.json'
+    saved_hashes = load_saved_hashes(hashes_file)
+
+    username = os.environ.get("MBOX_USER")
+    password = os.environ.get("MBOX_PASS")
+    default_folder = os.environ.get("MBOX_FOLDER", "Inbox")
+    host = os.environ.get("MAIL_HOST")
+    port = os.environ.get("MAIL_PORT")
+
+    if not username or not password:
+        logging.error('Missing mailbox username or password in environment')
+        sys.exit(1)
+
+    attachment_path = join(dirname(__file__), "attachments")
+    if not os.path.exists(attachment_path):
+        os.makedirs(attachment_path)
+
+    ssl_context = setup_ssl_context()
+
+    with MailBox(host, port=port, ssl_context=ssl_context).login(
+            username, password, default_folder) as mailbox:
+        process_attachments(mailbox, attachment_path, saved_hashes)
+
+    save_hashes(hashes_file, saved_hashes)
+
+if __name__ == "__main__":
+    main()