Neo4j batch index stream

A writable stream for batch indexing labeled nodes and relations into Neo4j. For example from a csv file or piped output. Before streaming, it will check if a connection to neo4j can be made, and optionally indexes can be set to speed up the inserting process.

$3

Given the following test.csv file:

``
Fabien|likes|Nick
Nick|dislikes|Fabien
Jochem|likes|Nick
Lydia|likes|Fabien
`


And the following example script, that uses neo4j-batch-index-stream. You can then run less test.csv | node.js main.js to pipe the contents of test.csv into main.js, which converts the csv into objects that can be batch inserted in neo4j.

`javascript
//// main.js

var through2 = require('through2');
var split2 = require('split2');
var Neo4jStream = require('neo4j-batch-index-stream');

var buildRecords = through2({ objectMode: true }, function(chunk, enc, callback) {
var line = chunk.toString().trim();

if (line && line.length) {
var parts = line.split("|");

var Left = {
"label": "Person",
"name" : parts[0],
}

var Right = {
"label" : "Person",
"name" : parts[2],
};

var relation = {
"relation" : parts[1],
"start" : Left,
"end" : Right,
}

this.push(Left);
this.push(Right);
this.push(relation);
}

callback();
});


var config = require("./secret-config.json");
var username = config.username;
var password = config.password; // your own password ;


var stream = new Neo4jStream(username, password, {
"index_key" : "name",
"highWaterMark" : 10000
});

stream.index([
["Person", "name"]
]);


process.stdin
.pipe(split2())
.pipe(buildRecords)
.pipe(stream)
.on('error', function(error) {
console.log(error);
})
.on('finish', function() {
console.log("DONE");
})
`

#### Result

!Neo4j database with people and relations

$3

Error: Error: connect ECONNREFUSED 127.0.0.1:7474
> Neo4j is not running or not available.

---

`
Error: {
"errors" : [ {
"message" : "Invalid username or password.",
"code" : "Neo.ClientError.Security.AuthorizationFailed"
} ]
}
`
> You either have the default neo4j/neo4j password or gave incorrect credentials.

$3

If you have neo4j running, you can do a simple batch insert with npm test`.

If you feel something is missing, you can open an issue stating the problem and desired result. If code is unclear give me a @mention. Pull requests are welcome.