Check out the Elastica documentation to find out how Elastica works. If you have questions, don't hestitate to ask them in the Elastica google group. Issues should go to the issue tracker from github.
PHP client for the distributed search engine elasticsearch which is based on Lucene and can be an alternative to solr. The client naming and structure is consistent with Zend Framework and other PHP frameworks. This makes it easy to use the client in combination with Zend Framework.
For changes in the API please check the file changes.txt
The version numbers are consistent with elasticsearch. The version number 0.16.0.0 means it is the first release for elasticsearch version 0.16.0. The next release is called 0.16.0.1. As soon as the elasticsearch is updated and the client is updated, also the next version is called 0.16.1.0. Like this it should be always clear to which versions the Elastica client is compatible.
At the moment the client should be backward compatible to PHP 5.2. That's the reason why the client was not directly built with namespaces and other nice PHP 5.3 features.
File upload is supported but the mapper attachement plugin has to be installed
./bin/plugin install mapper-attachments