I want to use Solr for indexing some library, that represent books in fb2 format. In fact fb2 is just xml with similar xsd format. But, post.jar ignores *.fb2 files, and I dont understand how to map values in fb2 file to index fields, like:
<book-title>some book</book-title>
...to "book-title" field in index. Should I create a plug-in, or something else?
You should look at the Solr Data Import Handler (DIH).
In the Solr examples folder you have an RSS import example. If you look in the rss-data-config.xml file you will see how they use the XPathEntityProcessor to map from XML to the Solr fields, e.g.:
Here is some more information: http://www.andornot.com/blog/post/Sample-Solr-DataImportHandler-for-XML-Files.aspx
I have also written Tika parsers in the past to work with specific file formats.
https://lucidworks.com/blog/2010/06/18/extending-apache-tika-capabilities/
For more flexibility you can just read your files using your favorite programming language and send the data to Solr using an API. We had to do this for a recent application as the DIH wasn't flexible enough for what we wanted to achieve.
