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Neocons, a Clojure client for the Neo4J REST API

Neocons is a feature rich idiomatic Clojure client for the Neo4J REST API.

Supported Features

Neocons currently supports the following features via the Bolt Protocol:

Cypher queries
Sessions
Transactions

Neocons currently supports the following features (all via REST API, so you can use open source Neo4J Server edition for commercial projects):

Create, read, update and delete nodes
Create, read, update and delete relationships
Fetch relationships for given node
Create and delete indexes
Index nodes
Query node indexes for exact matches and using full text search queries
Query automatic node index
Traverse nodes, relationships and paths
Find shortest path or all paths between nodes
Predicates over paths, for example, if they include specific nodes/relationships
Cypher queries
Basic HTTP authentication, including Heroku GrapheneDB add-on compatibility
Efficient multi-get via Cypher queries
Convenience functions for working with relationships and paths
Neo4J 2.0 transactions
Neo4J 2.0 labels
Neo4J 2.0 constraints

Documentation & Examples

To get started and see what using Neocons feels like, please use our Getting started with Clojure and Neo4J Server guide.

Documentation guides are mostly complete. For more examples, see our test suite.

Community

Neocons has a mailing list. Feel free to join it and ask any questions you may have.

To subscribe for announcements of releases, important changes and so on, please follow @ClojureWerkz on Twitter.

Project Maturity

Neocons is not a young project: first released in October 2011, it's been in production use from week 1.

It now supports Neo4j 3.x & 2.x release(s) and the API is stable. Documentation is in good shape, too.

Maven Artifacts

The Most Recent Release

Neocons artifacts are released to Clojars. If you are using Maven, add the following repository definition to your pom.xml:

<repository>
  <id>clojars.org</id>
  <url>http://clojars.org/repo</url>
</repository>

The Most Recent Stable Release

With Leiningen:

[tuddman/neocons "3.2.1-SNAPSHOT"]

With Maven:

<dependency>
  <groupId>clojurewerkz</groupId>
  <artifactId>neocons</artifactId>
  <version>3.2.0</version>
</dependency>

Continuous Integration

CI is hosted by travis-ci.org

Supported Clojure Versions

Neocons requires Clojure 1.8+. The most recent stable Clojure release (1.9) is highly recommended.

Supported Neo4J Server Versions

Neocons 3.2

Neocons 3.2 targets Neo4j Server 3.0.x & 3.1.x, and includes Neo4j's Bolt Protocol.

Neocons 3.1

Neocons 3.1 targets Neo4J Server 2.2.

Neocons 3.0

Neocons 3.0 targets Neo4J Server 2.0 and later versions. 1.9.x compatibility may be less than complete.

Neocons 2.0

Neocons 2.0 targets Neo4J Server 2.0, although the test suite also passes against 1.9.x.

There are incompatible changes in 1.9 and 2.0 in mutating Cypher syntax, so Neo4j Server 1.8 compatibility is less than perfect.

Neocons 1.1

Neocons 1.1 supports Neo4J Server 1.5.0 and later versions. For the Cypher query language support, 1.6 is the minimum recommended versions because Cypher is supported by the REST API directly without any plugins. Some features (in Cypher in particular) may be specific to a later version. We recommend using the most recent stable release. Neocons is actively tested against bleeding edge Neo4J Server snapshots and we try to support important new features before stable server releases come out.

If you use OpsCode Chef, there is a Neo4J Server Chef cookbook.

Neocons Is a ClojureWerkz Project

Neocons is part of the group of libraries known as ClojureWerkz, together with Monger, Langohr, Welle, Quartzite, Validateur and several others.

Development

Neocons uses Leiningen 2. Make sure you have it installed and then run tests against all supported Clojure versions using

lein all test

Then create a branch and make your changes on it. Once you are done with your changes and all tests pass, submit a pull request on Github.

The tests require a Neo4j on localhost on port 7474. An easy way to arrange for this if you do not generally run a local server may be to use docker:

docker run --publish=7474:7474 --publish=7687:7687 --volume=$HOME/neo4j/data:/data neo4j

and pass the default credentials to lein on the command line

NEO4J_LOGIN=neo4j NEO4J_PASSWORD=admin lein test

License

Double licensed under the Eclipse Public License (the same as Clojure) or the Apache Public License 2.0.

FAQ

Will embedding be supported in the future?

Because Neo4J is GPL software, linking against it will require your project to be open source. While there are perfectly valid use cases for this, Neocons was developed to be used in commercial projects and Neocons authors strongly prefer business-friendly licenses and Clojure community commitment to the Eclipse Public License v1.

Neocons namespace structure leave the door open for future Neo4J Server features like the binary protocol but it is highly unlikely that it will ever cover embedding, should Neo4J license stay GPL forever.

If you need a solid well-maintained EPLv1-licensed embeddable graph database for Clojure, please take a look at Titanium and Jiraph.