Cops(https://github.com/mikespub-org/seblucas-cops) by Sébastien Lucas, now maintained by MikesPub, stands for Calibre OPDS (and HTML) Php Server.

COPS links to your Calibre library database and allows downloading and emailing of books directly from a web browser and provides a OPDS feed to connect to your devices.

Changes in your Calibre library are reflected immediately in your COPS pages.

See : COPS's home(https://github.com/mikespub-org/seblucas-cops) for more details.

Don't forget to check the Wiki(https://github.com/mikespub-org/seblucas-cops/wiki).

Why? (taken from the author's site)

In my opinion Calibre is a marvelous tool but is too big and has too much
dependencies to be used for its content server.

That's the main reason why I coded this OPDS server. I needed a simple
tool to be installed on a small server (Seagate Dockstar in my case).

I initially thought of Calibre2OPDS but as it generate static file no
search was possible.

Later I added an simple HTML catalog that should be usable on my Kobo.

So COPS's main advantages are :

• No need for many dependencies.
• No need for a lot of CPU or RAM.
• Not much code.
• Search is available.
• With Dropbox / owncloud it's very easy to have an up to date OPDS server.
• It was fun to code.

If you want to use the OPDS feed don't forget to specify /feed at the end of your URL.