Mapping an attachment field
ElasticSearch allows you to extend its core types to cover new requirements with native plugins that provide new mapping types. The most-used custom field type is the attachment mapping type.
It allows you to index and search the contents of common documental files, such as Microsoft Office formats, open document formats, PDF, epub, and many others.
Getting ready
You need a working ElasticSearch cluster with the attachment plugin (https://github.com/elasticsearch/elasticsearch-mapper-attachments) installed.
It can be installed from the command line with the following command:
bin/plugin -install elasticsearch/elasticsearch-mapper-attachments/1.9.0
The plugin version is related to the current ElasticSearch version; check the GitHub page for further details.
How to do it...
To map a field as an attachment, it's necessary to set the type field to attachment.
Internally, the attachment field defines the fields property as a multifield that takes some binary data (encoded...