queries.js

var u = require('util')

var fs = require('fs')
var path = require('path')
var yaml = require('js-yaml')

var template = require('./utils/template')

// load queries from file
var fn = path.join(__dirname, 'queries.yaml')
var f = fs.readFileSync(fn, {encoding: 'utf8'})
var qs = yaml.safeLoad(f, {filename: fn})

// make cypher queries out of structure manipulation request
exports.mkQuery = function (request) {
  var structure = request.structure
  var operation = request.operation

  if (!qs[structure]) {
    throw new Error(u.format('No such structure "%s"', structure))
  }

  if (!qs[structure][operation]) {
    throw new Error(u.format('No such operation "%s" on "%s"', operation, structure))
  }

  if (!qs[structure][operation].cypher) {
    throw new Error(u.format('No cypher query defined for operation "%s" on "%s"', operation, structure))
  }

  // lookup query string and...
  var cypher_string = qs[structure][operation].cypher

  // ...string replace all occurances of «type»
  var s = template(cypher_string, {type: request.type})

  // neo4batch ready dictionary
  return {
    parameters: request,
    statement: s
  }
}

exports.structures = qs