Version 0.1.1 available at
http://charles.the-haleys.org/calibre/.
Changes:
1) made searching more like calibre (but not quite the same). It accepts most string searches, such as tags:=Science and tags:~aaa. Regexps are perl-compatible. If you begin the regexp with /, then the flags uses (e.g., ignore case) are the ones you provide at the end. Example: /AaAa/ is case sensitive. /AaAa/i is not. The search also accepts field:true or field:false in many cases. Searches for dates and numbers are not implemented.
2) added an option to restrict visible content to the results of a search (a restriction in calibre terms).
3) added
a demo library. It is my library (around 1200 books), restricted to some public domain books from Gutenberg and Diesel.