Account For Various Scenarios Spotify May Throw

[Kyrluckechuck]

Description

This PR accounts for a few scenarios that I encountered Spotify throwing while dealing with a playlist of > 2000 songs:

• The song added to the playlist may not be available to you, which can happen for a variety of reasons but the two most common being that your region was not included in the copyright license, or the song was "removed" from Spotify altogether
• The seektable request may refuse with a 403 response while using your authorized session, and falling back on a "generic" session appears to always resolve it
  • Discovered this one by simply visiting the URL in question and then re-running the download and it immediately working. It appears to be some sort of rate-limit that a generic request clears.
• Rate limit the decryption key requests for songs when the license is not correctly returned, this appears to typically mean you've been throttled
  • I found that waiting about a minute was enough in most circumstances, but if you want to avoid the client frequently hitting the limit, adding that 1 second delay between attempts appears to be enough to stop it from needing the ~60s delay
  • This attempts a few times, with 1 second delay first, then 60, 120, 180, 240, and then finally letting it continue (at which point it will raise a different error further down)
  • This never had more than a 1 second delay for me, so the > 60 options should not be encountered if the 1 second delay is kept (when running it on the remaining ~1300 songs in the playlist)
• Some songs have different copyright classes (specifically songs from artists that are typically "unlicensed")
  • I don't know if it made sense to include that copyright information instead, but could not locate a reason for a P license vs a T license (one of the example songs I had returned that type), so I went the route of simply "ignoring it" and just marking the text as ''

Notes

This took a couple creative liberties based on me not specifically caring about certain things in how it was parsed and just wanted it to work, so I'm open to suggestions here 😄

[Kyrluckechuck]

@glomatico any strong reason why you closed this?

[glomatico]

Sorry lol I messed with the branches when creating the dev branch and it closed your pull request. @Kyrluckechuck

[Kyrluckechuck]

@glomatico gotcha! Yeah if you re-open this, I'm happy to rebase this when I've got some free time at some point 😅