Improve the robustness of the prompt (especially on Windows)

README.md

@@ -25,7 +25,7 @@ Now, the instructions are similar for Chrome and Firefox:
 3. **Chrome**: go to the "Application" tab. **Firefox**: go to the "Storage" tab ("Web-Speicher").
 4. Un-collapse "Cookies".
 5. In the list, search for a cookie with the name `connect.sid`
-6. Select and copy the value.
+6. Select and copy the value. It must start with the character sequence `s%3A`.
 
 
 ### 2. Execute the script via the command line

codimd_export.py

@@ -4,13 +4,17 @@ Save all Markdown documents in your CodiMD history to a local directory.
 """
 
 import json
-import os
 import sys
-from getpass import getpass
 from pathlib import Path
 from urllib.error import HTTPError
 from urllib.request import Request, urlopen
 
+if not sys.platform.startswith("win"):
+    from getpass import getpass
+else:
+    # on Windows, Ctrl-V doesn't work with getpass()
+    getpass = input
+
 
 def slurp(url, session_id):
     """Retrieve a (protected) CodiMD resource and return it as a bytes object."""
@@ -56,10 +60,10 @@ def main(instance_url, session_id, export_to):
 
 def get_sessionid():
     """Ask the user for the session id, if it's not configured as an envvar."""
-    try:
-        return os.environ["CMD_SESSIONID"]
-    except KeyError:
-        return getpass("Please provide your CodiMD session id (connect.sid cookie): ")
+    sid = getpass("Please provide your CodiMD session id (connect.sid cookie): ")
+    if sid.startswith("s%3A"):
+        return sid
+    raise SystemExit(f"error: the supplied session id seems to be malformed")
 
 
 if __name__ == "__main__":