Run go run main.go inside blinkist/ folder to produce books_urls.txt, the list of unduplicated URLs of all of the books.
Run go run download.go inside download/ folder to start downloading audio files from the above URLs. books_urls.txt must be present in the download/ folder!
Technical details of the solution
Look for HTML tag data-book-id e.g."5c28f2fc6cee070008e7a3d7" in each book URL.
Look for all HTML tags data-chapterNo e.g."1" and corresponding data-chapterId e.g."5c28f3296cee070007b46369" (both on the same line) from each book URL.
Construct this API link to get the short-lived download link: https://www.blinkist.com/api/books/<data-book-id>/chapters/<data-chapterId>/audio.
(e.g.https://www.blinkist.com/api/books/5c28f2fc6cee070008e7a3d7/chapters/5c28f3296cee070007b46369/audio).
If the book contains audio (the previous step returns something), create a folder based on JavaScript tag e.g."reader:book:title:changed", "Bad Blood" on the local drive.
Decode to proper URL, (replace \u0026 with &), e.g.:
https://abcdefgh12345.cloudfront.net/5c28f2fc6cee070008e7a3d7/5c28f3296cee070007b46369.m4a?Expires=1234567890&Signature=abcdefghijklmnopqrstuvwxyz1234-567890abcde-fghi~jklmnopqrstuvwxyz1234567890abcdefgh~jklmnopqrstuvwxyz1234567890abcdefgh-abcd~abcdefghijklmnopqrstuvwxyz1234-567890abcde~jklmnopqrstuvwxyz1234567890abcdefgh-jklmnopqrstuvwxyz1234567890abcdefgh-567890abcde__&Key-Pair-Id=ABCDEFGHIJKLMNOPQRST
Download the chapter using the above link as the m4a file. Filename will be based on data-chapterNo and stored in the book title folder, e.g.:
Bad Blood/000.m4a,
Bad Blood/001.m4a,
Bad Blood/002.m4a,... .