Calibre Web opds access failing as content server

[rmzg]

Hey,

I recently found a program that acts as very nice and fully featured web browser for a calbre library called 'Calibre Web': https://github.com/janeczku/calibre-web

It installed and started working pretty easily but when I attempt to configure its url as a content server inside calibre companion, it refuses to past the "index" page.

CC will connect to the url fine and show me the first page with a list of categories, but when I click on the categories themselves, nothing happens. The search action will actually find books that match but again I can't actually open the links it returns.

I've verified that the links do work in a web browser both on my phone client and a laptop, so I assume there's something slightly off in the format it's returning the opds data in?

Here's an example of the index page it returns:

<?xml version="1.0" encoding="UTF-8"?>
<feed xmlns="http://www.w3.org/2005/Atom">
  <id>urn:uuid:2853dacf-ed79-42f5-8e8a-a7bb3d1ae6a2</id>
  <link rel="self" href="/opds" type="application/atom+xml;profile=opds-catalog;kind=navigation"/>
  <link rel="start" title="Start" href="/opds"
        type="application/atom+xml;profile=opds-catalog;kind=navigation"/>
  <link title="Search" type="application/atom+xml" href="/opds/search?query={searchTerms}" rel="search"/>
  <title>Calibre-web</title>
  <author>
    <name>Calibre-web</name>
    <uri>https://github.com/janeczku/calibre-web</uri>
  </author>
  <entry>
    <title>Hot Books</title>
    <link rel="http://opds-spec.org/sort/popular" href="/opds/hot" type="application/atom+xml;profile=opds-catalog"/>
    <id>/opds/hot</id>
    <content type="text">Popular publications from this catalog based on Downloads.</content>
  </entry>
  <entry>
    <title>Best rated Books</title>
    <link rel="http://opds-spec.org/recommended" href="/opds/rated" type="application/atom+xml;profile=opds-catalog"/>
    <id>/opds/rated</id>
    <content type="text">Popular publications from this catalog based on Rating.</content>
  </entry>
  <entry>
    <title>New Books</title>
    <link rel="http://opds-spec.org/sort/new" href="/opds/new" type="application/atom+xml;profile=opds-catalog"/>
    <id>/opds/new</id>
    <content type="text">The latest Books</content>
  </entry>
  <entry>
    <title>Random Books</title>
    <link rel="http://opds-spec.org/featured" href="/opds/discover" type="application/atom+xml;profile=opds-catalog"/>
    <id>/opds/discover</id>
    <content type="text">Show Random Books</content>
  </entry>

  <entry>
    <title>Read Books</title>
    <link rel="subsection" href="/opds/readbooks/" type="application/atom+xml;profile=opds-catalog"/>
    <id>/opds/readbooks/</id>
    <content type="text">Read Books</content>
  </entry>

  <entry>
    <title>Unread Books</title>
    <link rel="subsection" href="/opds/unreadbooks/" type="application/atom+xml;profile=opds-catalog"/>
    <id>/opds/unreadbooks/</id>
    <content type="text">Unread Books</content>
  </entry>
  <entry>
    <title>Authors</title>
    <link rel="subsection" href="/opds/author" type="application/atom+xml;profile=opds-catalog"/>
    <id>/opds/author</id>
    <content type="text">Books ordered by Author</content>
   </entry>
   <entry>
    <title>Category list</title>
    <link rel="subsection" href="/opds/category" type="application/atom+xml;profile=opds-catalog"/>
    <id>/opds/category</id>
    <content type="text">Books ordered by category</content>
   </entry>
   <entry>
    <title>Series list</title>
    <link rel="subsection" href="/opds/series" type="application/atom+xml;profile=opds-catalog"/>
    <id>/opds/series</id>
    <content type="text">Books ordered by series</content>
   </entry>
   <entry>
    <title>Public Shelves</title>
    <link rel="subsection" href="/opds/shelfindex/public" type="application/atom+xml;profile=opds-catalog"/>
    <id>/opds/shelfindex/public</id>
    <content type="text">Books organized in public shelfs, visible to everyone</content>
   </entry>
   
   <entry>
    <title>Your Shelves</title>
    <link rel="subsection" href="/opds/shelfindex/" type="application/atom+xml;profile=opds-catalog"/>
    <id>/opds/shelfindex/</id>
    <content type="text">User's own shelfs, only visible to the current user himself</content>
   </entry>
   
</feed>

[DoctorOhh]

The CC FAQ states the following.

Does CC's content server connection work with other OPDS web servers?

No. The CC content server connection requires calibre's content server. It does not work with other servers such as COPS or a calibre-to-opds-generated server.

Note that it might appear to work with non-calibre servers, but CC will fail to download books.

[rmzg]

Oh.

Why? Can it be fixed?

[chaley]

CC won't be changed. I added special support to the calibre server to handle getting full metadata and identifying books on the device. I am not interested in reducing CC functionality to support non-calibre servers.

[rmzg]

I actually meant more changing the output of Calibre Web's opds.

What exactly is CC expecting to see when it makes the request? Is this documented someplace?

[DoctorOhh]

Originally Posted by rmzg

I actually meant more changing the output of Calibre Web's opds.

You might be best accessing the Calibre Web's opds program directly from Moon+ Reader or other program designed to access an OPDS feed.

[chaley]

Originally Posted by rmzg

I actually meant more changing the output of Calibre Web's opds.

What exactly is CC expecting to see when it makes the request? Is this documented someplace?

No. That said, you can use calibre's server log to see CC's queries and the server responses. Calibre is open source and you can look at the code to see how it generates responses to CC's queries, including the content of the various json dictionaries calibre passes back to CC.

I suggest that you use a calibre V2 server unless the server you are changing supports multiple libraries.

[rmzg]

What exactly is a calibre "v2 server"? Like, where would you get/run it and what would that difference be?

Also, will calibre-server complain if its metadata.db is changed out from underneath it? How often does it actually read the database?

[chaley]

Originally Posted by rmzg

What exactly is a calibre "v2 server"? Like, where would you get/run it and what would that difference be?

Calibre has had four major versions, 0, 1, 2, and 3. A "V2" server is a server running calibre V2, for example this one. A "V3" server is one running a current calibre release. The reason I suggested a V2 server is that V3 supports changing libraries. CC recognizes this fact and changes the URLs somewhat to make use of the feature.

As for where you would run it: up to you. Personally I would do development using a server attached to a calibre GUI instance. I run my production server on a Linode VPS.

Also, will calibre-server complain if its metadata.db is changed out from underneath it?

No. However, depending on the calibre version it may or may not notice.

How often does it actually read the database?

If memory serves me correctly, a V2 server reads the DB at startup. Depending on the underlying OS, it may reread the DB if it changes. I recall that on my Linux VPS the calibre V2 server never reread the DB. I used monit to detect a DB change and restart the server.

A V3 server will reread the DB if its timestamp changes.

It would be better to ask server questions on the dedicated server subforum in calibre. Kovid (author of calibre) hangs around there and can give definitive answers. I also check that subforum so could chime in if there is a CC interaction question or if you are asking about calibre code I wrote (not much in the server itself).