streamsql/lib/drivers/mysql.js

Streaming SQL ORM

const Stream = require('stream')
module.exports = function MysqlDriver() {
  const mysql = require('mysql')

  return {
    connect: function connect(opts, callback) {
      const conn = mysql.createConnection(opts)
      conn.connect(callback)
      return conn
    },
    close: function close(connection, callback) {
      return connection.end(callback)
    },
    getQueryFn: function getQueryFn(connection) {
      return function (sql, params, callback) {
        const opts = { sql: sql }
        return connection.query(opts, params, callback)
      }
    },
    getStreamFn: function getStreamFn(connection) {
      // will be in the context of `db`
      // expected to return a stream
      return function streamQuery(sql, opts) {
        const stream = new Stream()
        const queryStream = this.query(sql)
        const handlers = this.driver.streamHandlers(stream, opts)

        stream.pause = connection.pause.bind(connection)
        stream.resume = connection.resume.bind(connection)

        queryStream.on('result', handlers.row)
        queryStream.on('end', handlers.done)
        queryStream.on('error', stream.emit.bind(stream, 'error'))
        return stream
      }
    },
    putShouldUpdate: function (err, opts) {
      opts = opts || {}
      const message = err.message
      const code = err.code
      var uniqueKey
      if (opts.uniqueKey) {
        uniqueKey = typeof opts.uniqueKey === 'string'
          ? [opts.uniqueKey]
          : opts.uniqueKey
      } else {
        uniqueKey = []
      }
      const primaryKeyError = message.match(/for key .*?PRIMARY/)
      const uniqueKeyError = uniqueKey.reduce(function (result, key) {
        return result || message.indexOf("'" + key + "'") > -1
      }, false)
      return ((code == 'ER_NO_DEFAULT_FOR_FIELD') ||
              (code == 'ER_DUP_ENTRY' && primaryKeyError || uniqueKeyError))
    }
  }
}