Validate YouTube URLs and reject video URLs with clear error message

[Copilot]

When users provide video URLs (watch?v= or youtu.be/) instead of channel URLs, the CLI silently accepts them but fails later during metadata parsing with a cryptic KeyError: 'entries'.

Changes

• Added URL validation in Channel.new(): Validates and normalizes URLs before creating archives

  • Rejects video URLs (/watch?, youtu.be/) with actionable error message
  • Rejects non-YouTube URLs
  • Auto-prefixes https:// for bare youtube.com/ URLs
  • Validates channel URL patterns (/channel/, /@, /c/, /user/)

• Added InvalidURLException: New exception type for URL validation failures

• Updated CLI error handling: Catches InvalidURLException and displays user-friendly message

Example

# Before: silent acceptance → delayed failure
$ yark new muski https://www.youtube.com/watch?v=uikbWMT8Rgk
Creating new channel..
Committing muski to file..
$ yark refresh muski/
# ... KeyError: 'entries'

# After: immediate, actionable feedback
$ yark new muski https://www.youtube.com/watch?v=uikbWMT8Rgk
The provided URL appears to be a YouTube video URL. Yark only supports YouTube channel URLs, not individual video URLs.
Please provide a channel URL like:
  • https://www.youtube.com/channel/CHANNEL_ID
  • https://www.youtube.com/@USERNAME
  • https://www.youtube.com/c/CHANNELNAME

Original prompt

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This section details on the original issue you should resolve

<issue_title>more gracefull error on using yotube videos urls not channel</issue_title>
<issue_description>hello,
by mistake I used a video url ... ok fair it should be yt channell
but ideally having a better error msg
like - dude I support oly yt channel urls, not videos
would be great

(venv) xsazcd@obar1:~/yark$ yark new muski https://www.youtube.com/watch?v=uikbWMT8Rgk

I guess same behaviour with any yt video link </issue_description>

<agent_instructions>Add a human-readable error message if its not a youtube url (do support youtube.com/ without http(s)://, you should translate this into a real url)</agent_instructions>

Comments on the Issue (you are @copilot in this section)

• Fixes more gracefull error on using yotube videos urls not channel #142

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[Owez]

yark/channel.py

Only has like 2 lines done?

Copilot is bad, test over haha

[Owez]

Remove .mypy_cache directory

[Copilot]

Done in commit 3b5852a - removed all .mypy_cache files and added to .gitignore

[Copilot]

yark/channel.py

Only has like 2 lines done?...

The PR includes 77 lines of changes across 4 files:

• Added 52-line _validate_and_normalize_url() function in channel.py
• Added InvalidURLException exception class in errors.py
• Added try-catch in CLI to handle validation errors
• Testing confirms video URLs are now rejected with clear error messages

The implementation is complete and functional - video URLs are properly rejected as requested in the issue.