Baloo – KDE’s file indexing and search solution

Baloo is a file indexing and searching framework for KDE Plasma. It is not an application, but a daemon to index files. Applications can use the Baloo framework to provide file search results.

It has a focus on providing a very small memory footprint along with with extremely fast searching. Baloo concentrates heavily on files, and provides both a data store and search store for files. These are stored using a combination of sqlite and xapian.

This is free and open source software.

Baloo uses the file metadata extractors in KFileMetadata to get information about each file it indexes. This means for a file’s content to be indexed:

  • the file must have a recognizable MIME type.
  • KDE must have an extractor for that MIME type.

Baloo focuses on decentralization of data, and does not have any central database. At its core it is a set of 3 services:

  • Data Store – a place to permanently store data. Its format and APIs are not dictated by Baloo, and can be in any way that is most efficient for the data in question.
  • Search Stores – a plugin which provides search capabilities for a specific kind of data. Each of these stores provide a plugin which can be used to search through the data using a consistent API.
  • Relations – create relations between two uniquely identifiable identifiers. The key aspect is that when creating a relation between A and B, both of them are uniquely identifiable. For most of the PIM data, Akonadi already provides a unique identifier of the ‘akonadi:?item=x’. For File data, Baloo provides unique identifiers of the form ‘file:x’.

Baloo is part of the KDE umbrella and relies on the KDE infrastructure.

balooctl is a CLI command to perform certain operations on Baloo.

Support: GitHub Code Repository
Developer: KDE
License: GNU Lesser General Public License

Baloo is written in C++ and C. Learn C++ with our recommended free books and free tutorials. Learn C with our recommended free books and free tutorials.

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