Confluence 7.0 and later
The Attachment Text Extractor module allows plugins to index the contents of a particular attachment type (for example, OpenOffice documents or Flash files). Unlike a normal extractor (see Extractor2 module), text extracted by the Attachment Text Extractor plugin module is stored as an artifact along with attachment content. It can be be reused to avoid an unnecessary extraction process each time the metadata of a page containing the attachment is modified.
See our Create an attachment text extractor tutorial for a step-by-step example.