Awesome Procedures for Neo4j 5.5.0.x (Extended)

Introduction

Neo4j 3.x introduced the concept of user-defined procedures and functions. Those are custom implementations of certain functionality, that can’t be (easily) expressed in Cypher itself. They are implemented in Java and can be easily deployed into your Neo4j instance, and then be called from Cypher directly.

As of 5.0 APOC has been split into separate repositories, one being the main, officially supported, APOC Library. The other belonging to APOC Extended. This repository handles the extended part of APOC.

There are over 150 different procedures and functions in the Extended APOC library. Their purpose is to increase functionality in areas such as data integration, graph algorithms and data conversion.

License

Apache License 2.0

"APOC" Name history

Apoc was the technician and driver on board of the Nebuchadnezzar in the Matrix movie. He was killed by Cypher.

APOC was also the first bundled A Package Of Component for Neo4j in 2009.

APOC also stands for "Awesome Procedures On Cypher"

Feedback

Please provide feedback and report bugs as GitHub issues or join the Neo4j Community Forum and ask with the APOC tag.

Calling Procedures & Functions within Cypher

User defined Functions can be used in any expression or predicate, just like built-in functions.

Procedures can be called stand-alone with CALL procedure.name();

But you can also integrate them into your Cypher statements which makes them so much more powerful.

Load JSON example

WITH 'https://raw.githubusercontent.com/neo4j-contrib/neo4j-apoc-procedures/5.4/src/test/resources/person.json' AS url

CALL apoc.load.json(url) YIELD value as person

MERGE (p:Person {name:person.name})
   ON CREATE SET p.age = person.age, p.children = size(person.children)

APOC Procedures & Functions Overview

All included procedures are listed in the overview in the documentation and detailed in subsequent sections.

Built in Help

call apoc.help('keyword')

lists name, description, signature, roles, based on keyword

Detailed Feature Documentation

See the APOC User Guide for documentation of each of the major features of the library, including data import/export, graph refactoring, data conversion, and more.

Procedure & Function Signatures

To call procedures correctly, you need to know their parameter names, types and positions. And for YIELDing their results, you have to know the output column names and types.

INFO:The signatures are shown in error messages, if you use a procedure incorrectly.

You can see the procedure’s signature in the output of CALL apoc.help("name")

CALL apoc.help("dijkstra")

The signature is always name : : TYPE, so in this case:

apoc.algo.dijkstra
 (startNode :: NODE?, endNode :: NODE?,
   relationshipTypesAndDirections :: STRING?, weightPropertyName :: STRING?)
:: (path :: PATH?, weight :: FLOAT?)

Table 1. Parameter Explanation

Name	Type
Procedure Parameters
startNode	Node
endNode	Node
relationshipTypesAndDirections	String
weightPropertyName	String
Output Return Columns
path	Path
weight	Float

Manual Installation: Download the latest release

Since APOC relies on Neo4j’s internal APIs you need to use the matching APOC version for your Neo4j installation. Make sure that the first two version numbers match between Neo4j and APOC.

Go to here for all the APOC extended releases and download the binary jar to place into your $NEO4J_HOME/plugins folder.

Manual Configuration

Warning

For security reasons, procedures and functions that use internal APIs are disabled by default. Loading and enabling APOC procedures and functions can be configured using the Neo4j config file. For more details, see the APOC installation documentation.

Version Compatibility Matrix

Since APOC relies in some places on Neo4j’s internal APIs you need to use the right APOC version for your Neo4j installaton.

APOC uses a consistent versioning scheme: <neo4j-version>.<apoc> version. The trailing <apoc> part of the version number will be incremented with every apoc release.

apoc version	neo4j version
5.5.0	5.5.0 (5.5.x)
5.4.0	5.4.0 (5.4.x)
5.3.1	5.3.0 (5.3.x)
5.2.0	5.2.0 (5.2.x)
5.1.0	5.1.0 (5.1.x)
4.4.0.13	4.4.0 (4.4.x)

Using APOC with the Neo4j Docker image

To use APOC with Docker; download the APOC release matching your Neo4j version and copy it to a local folder, supplying it as a data volume mounted at /plugins.

The following downloads the APOC Library into the plugins directory and then mounts that folder to the Neo4j Docker container

mkdir plugins
pushd plugins
wget https://github.com/neo4j-contrib/neo4j-apoc-procedures/releases/download/5.5.0/apoc-5.5.0-extended.jar
popd
docker run --rm -e NEO4J_AUTH=none -p 7474:7474 -v $PWD/plugins:/plugins -p 7687:7687 neo4j:5.4

If you want to pass custom apoc config to your Docker instance, you can use environment variables, like here:

docker run \
    -p 7474:7474 -p 7687:7687 \
    -v $PWD/data:/data -v $PWD/plugins:/plugins \
    --name neo4j-apoc \
    -e NEO4J_apoc_export_file_enabled=true \
    -e NEO4J_apoc_import_file_enabled=true \
    -e NEO4J_apoc_import_file_use__neo4j__config=true \
    neo4j

Build & install the current development branch from source

git clone https://github.com/neo4j-contrib/neo4j-apoc-procedures
cd neo4j-apoc-procedures
sudo ./gradlew --init-script init.gradle shadow
cp build/extended/libs/apoc-<version>-extended.jar $NEO4J_HOME/plugins/
$NEO4J_HOME/bin/neo4j restart

A full build including running the tests can be run by sudo ./gradlew --init-script init.gradle build.

Note that --init-script init.gradle is not needed if you already loaded the gradle changes (e.g. via IntelliJ)

Applying Code-style

./gradlew spotlessApply

To apply the spotless code-style, run the above gradle command, this will remove all unused imports