prisme-flow/nodes/bridge/cassandra/cassandra.js

prisme platform flow engine

/**
 * Created by prisme.io on 09/06/2017.
 */

module.exports = function (RED) {
  'use strict'
  var cassandra = require('cassandra-driver')

  function CassandraNode (n) {
    RED.nodes.createNode(this, n)
    this.hosts = n.hosts
    this.port = n.port

    this.connected = false
    this.connecting = false

    this.keyspace = n.keyspace
    var node = this

    function doConnect () {
      node.connecting = true

      var authProvider = null
      if (node.credentials.user) {
        authProvider = new cassandra.auth.PlainTextAuthProvider(
                    node.credentials.user,
                    node.credentials.password
                )
      }

            // TODO: Support other port, default is 9042
      node.connection = new cassandra.Client({
        contactPoints: node.hosts.replace(/ /g, '').split(','),
        keyspace: node.keyspace,
        authProvider: authProvider
      })

      node.connection.connect(function (err) {
        node.connecting = false
        if (err) {
          node.error(err)
          node.tick = setTimeout(doConnect, 30000)
        } else {
          node.connected = true
        }
      })
    }

    this.connect = function () {
      if (!this.connected && !this.connecting) {
        doConnect()
      }
    }

    this.on('close', function (done) {
      if (this.tick) { clearTimeout(this.tick) }
      if (this.connection) {
        node.connection.shutdown(function (err) {
          if (err) { node.error(err) }
          done()
        })
      } else {
        done()
      }
    })
  }
  RED.nodes.registerType('CassandraDatabase', CassandraNode, {
    credentials: {
      user: {type: 'text'},
      password: {type: 'password'}
    }
  })

  function CassandraNodeIn (n) {
    RED.nodes.createNode(this, n)
    this.mydb = n.mydb
    this.mydbConfig = RED.nodes.getNode(this.mydb)

    if (this.mydbConfig) {
      this.mydbConfig.connect()
      var node = this
      this.on('input', function (msg) {
        var batchMode = Array.isArray(msg.topic)
        if (!batchMode && typeof msg.topic !== 'string') {
          node.error('msg.topic : the query is not defined as a string or as an array of queries')
          return
        }
        var resCallback = function (err, result) {
          if (err) {
            node.error(err, msg)
          } else {
            msg.payload = result.rows
            node.send(msg)
          }
        }

        if (batchMode) {
          node.log('Batching ' + msg.topic.length + ' CQL queries')
          node.mydbConfig.connection.batch(msg.topic, {prepare: true}, resCallback)
        } else {
          node.log('Executing CQL query: ', msg.topic)
          var params = msg.payload || []
          node.mydbConfig.connection.execute(msg.topic, params, {prepare: true}, resCallback)
        }
      })
    } else {
      this.error('Cassandra database not configured')
    }
  }
  RED.nodes.registerType('cassandra', CassandraNodeIn)
}