One feature of calibre is its ability to download news from many providers on the internet. When you set up a news download, you can tell calibre how many days to keep the "books" that the news download produces. In addition, you can tell calibre to automatically send news books to a device when that device connects. In CC's case, this transfer will happen any time CC connects as a wireless device, either manually or using CC's automatic connection option. See Can CC automatically connect and download news?
As of CC V3.6.8, CC can mimic calibre's automatic delete after some number of days. To do this, go to CC's settings and scroll to near the bottom, looking for the "Delete older news" option. Tap that option to see the three settings that CC needs:
- A checkbox telling CC that it is permitted to delete older news books.
- The tag that calibre automatically puts on news books. This tag depends on the user interface language being used in calibre, not CC. If you are not running calibre in English then you should check in calibre's tag browser for the value of this tag. You must enter that tag here spelled exactly as in calibre, including upper and lower case characters.
- The number of days that must pass after a news book is downloaded into CC before CC can delete it. Note that a "day" is actually a 24-hour period. If you download news at 7 in the morning and set this option to 1 day, the news books are eligible to be deleted after 7 in the morning the next day.
CC will check to see if books are to be deleted at one minute after midnight every day. For example, if you enter zero into the setting, all news books will be deleted at the next midnight. If you enter 1, news books will be deleted at the second midnight after they are downloaded to CC. And so on.
It could be that you want to keep books from different news sources for different numbers of days. CC will check for a special tag on the news book to determine if the time-before-delete is different. To set up a different delay, in calibre:
- Click on Fetch News
- Click on Scheduled to see the news sources you have set up
- Click on the news source that you want to keep books for shorter or longer than the time you entered into CC.
- Click the Advanced tab
- Enter cc_delete_after_N into the Extra Tags box, where N is the number of days you want CC to keep books generated by this news source. For example, if you want CC to keep them for 10 days, enter cc_delete_after_10. N can be larger or smaller than the number in CC's settings.
CC logs automatic deletion successes and failures to the autoconnect log. You can see this log by going to CC's Settings, scrolling down to Wireless Device Connection, then tapping View automatic connection log.