[Bug] OPDS: 'Error Parsing Catalog feed...' when using Calibre-Web Server

[caslicco]

Describe the bug

I get an error saying Error parsing Catalog feed. Please check the URL and try again. I am unable to find a way to get more specific details about the error.
I have tried accessing the Catalog from Calibre-Web using the "Moon+ Reader", and I am able to access the catalog and books. So I have concluded that the issue arises only when using Readium.
Also, I tried adding the 'Elephant Editions' Catalog (https://www.elephanteditions.net/opds), which works. I have compared the .atom files from 'Calibre-Web' and 'Elephant Editions' and noticed no difference.

How to reproduce?

1. Add a new OPDS Catalog in Readium with the URL: http://3.111.169.159:5000/opds, where you can access a sample catalog of 4 books through the Calibre-Web server.
2. Try adding the same catalog in 'Moon+ Reader' to verify that the catalog is indeed working.

Readium version

4.8.0

Android API version

31

Additional context

PS: I hope Readium supports 'authenticated access' to OPDS feeds, i.e., a way to access the catalog using a user's Login credentials.
Ideally, the Calibre-Web server requires the user to input login credentials to access the catalog; a requirement I have disabled for testing purposes.

[mickael-menu]

Could you share the content of the OPDS feed that is not being parsed? Thanks.

[caslicco]

Hi, thanks for responding. I have attached the opds.atom feed as a text file as well as the Calibre Library of the 4 .epub books.

TestLibrary.zip

[opds.atom From Calibre Web].txt

[stevenzeck]

@caslicco can you comment with a fresh URL for the feed? It parses the one from the txt file properly.

[mikespub]

After uninstalling release 3.0.1 and installing release 3.1.0 I noticed that:

a. new OPDS catalogs with http:// instead of https:// now generate the error as above, instead of parsing & showing the OPDS feed - this might be due to changes in the android security model and restrictions on insecure links
b. new OPDS catalogs with https:// now seem to fail silently or don't display a new catalog anyway - not sure what changed here

Either way, it's no longer possible to create new OPDS catalogs with the test app in release 3.1.0. The two default demo catalogs still seem to work...

[caslicco]

@mikespub Why do you think the two default demo catalogs still seem to be working. What might have they done right? I have also tested with the OPDS Catalog from ElephantEditions, and it works.
@stevenzeck Could you please tell me how to get it working by using an .atom file directly? And if it is working that way, can I create a separate workflow to cache the catalog and then load it in the app?

Thanks