Fast websocket based Cypher endpoint as Neo4j kernel extension
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Readme.md

Remoting Experiments for Neo4j's Cypher using MessagePack and WebSockets

Usage

  • right now queries are hard coded in clients
    ./server.sh [db-dir]
    node ws-client.js

Sample Session

    Request
    {"query","start n=({ids}) return n", "params": {"ids" : [1,2]},"stats": true,"result":true}

    Response:
    ["n"]
    [{"id":1,"data":{"name":"foo"}}]
    [{"id":2,"data":{"name":"bar"}}]
    {"time": 0, "rows": 2, "bytes": 100}

Ideas:

Write a Cypher only endpoint for Neo4j that uses a fast transport and serialization across multiple client languages. Cypher Results are streamed from the server. Transaction support. Multithreaded clients and servers Client examples in ruby, python, php, c#, c, javascript, java, scala, clojure, erlang Public installation on Heroku for testing

Serialization

Nodes, Relationships and Paths are converted into maps and lists for serialization recursively

Node : { id : id, [data : {foo:bar}]}
Relationship : { id : id, start: id, end: id, type : "FOO",  [data : {foo:bar}]}
Path {start: node, nodes: [nodes], relationships [relationships], end: node, lenght: 1}

Header with Columns, optional Footer with time, bytes, tx-id, error, exception, rows, update-counts for nodes, relationships, properties.

Compactness

  • leave off footer, enable when needed
  • ignore results (fire & forget)

Transactions

  • provide a "tx" parameter with begin, commit,rollback
  • tx-id will be reported in footer
  • provie a tx-id parameter with the transaction id
  • transaction will be suspended, resumed per request (if a tx-id is provided) and finished and removed at rollback/commit

Serialization

  • fast, lightweight, portable

MessagePack

Transport

  • fast, lightweight, portable

WebSockets

Java

  • uses netty 4

Running as Neo4j Kernel Extension

The cypher server is now packaged as a Neo4j Kernel Extension. So if you build the jar with mvn package and drop the jar in your neo4j environment either in /server/plugins or your classpath/build repository for embedded development, the extension will be started and listen on port 5555 by default.

The server starts by default with 1 Thread, the multiple threads don't work yet with transactions (wrong transactions resumed in the wrong thread) but for non-transactional access the single server works fine. Threads and port can be configured in neo4j.properties or in the config-map passed to the database.

   cypher_remoting_address=:5555 # a hostname and port 
   cypher_remoting_threads=1 # number of threads 1 to 10

Node.js

  • uses "ws" npm module
  • simple sample client

Resources

Websockets

  • Netty:
  • Node.js

MessagePack

Alternatives: