Lua-Neo4j

Unofficial library for communication with Neo4j database over bolt tcp protocol.

Install

Download this repository and use source code from src.

Or you can install it from https://luarocks.org/modules/stefanak-michal/bolt

luarocks install bolt

Usage

local bolt = require('bolt')
bolt.init({scheme = 'basic', principal = 'neo4j', credentials = 'neo4j'})
local result, err = bolt.query('RETURN 1 as num, $str as str', {str = 'Hello'})

Aura

local bolt = require('bolt')
bolt.setHost('abcxyz.databases.neo4j.io') -- without neo4j+s://
bolt.setSSL({mode = 'client', protocol = 'any', verify = 'none', dane = true})
bolt.init({scheme = 'basic', principal = 'neo4j', credentials = 'password'})
local result, err = bolt.query('RETURN 1 as num, $str as str', {str = 'Hello'})

More options for Luasec (setSSL) described here.

Methods

Name	Description	Arguments
setHost	Set hostname for connection.	string ip = 127.0.0.1
setPort	Set port for connection.	int port = 7687
setSSL	set configuration for secure connection.	table params = nil
setVersions	Set requested bolt versions.	number/string ... = 4.4, 4.3
init	Connect to database with credentials.	table auth info
query	Execute query and get records with associated keys. Shortcut for run and pull.	string cypher, table params, table extra
run	Execute query and get meta informations.	string cypher, table params, table extra
pull	Pull records from last run. Last record is meta informations.	table extra = {n = -1}
discard	Discard records from last run.	table extra = {n = -1}
begin	Begin transaction.	table extra = {}
commit	Commit transaction.
rollback	Rollback transaction.
reset	Reset connection to initial state.
route	Send route message.	table routing, table bookmarks, string db

Check official documentation for more informations.

Specific Neo4j types

Neo4j support two array data types which are not available in Lua. Lua has only table type. You have to specify type with key neotype in your table. You can use helper functions to add it. Available types are list, dictionary and Neo4j structures. Response doesn't contains neotype key for list and dictionary.

-- List
local result, err = bolt.query('RETURN $list AS list', {
  ['list'] = bolt.list({34, 65})
})
-- Dictionary
local result, err = bolt.query('RETURN $dict AS dict', {
  ['dict'] = bolt.dictionary({['one'] = 1, ['two'] = 2})
})

Another issue is with nil while Neo4j has null type. If you set nil into table value in Lua, key is removed from table while Neo4j expects key (in query parameters) even with null value. If you are looking how to set null we introduce to you another specific type. You can use helper function to generate it.

local result, err = bolt.query('RETURN $n AS n', {
  ['n'] = bolt.null()
})

-- Response from server is not decoded into table with neotype, because Lua can handle missing key as nil.
-- result: {1 = {}}

Requires

• Lua >= 5.3
• Luasocket
• Luasec - if you need SSL
• Neo4j >= 3