ezpaarse-project/ezpaarse

'use strict';

/**
 * Sets the array containing the fields to use when writing ECs
 * @param  {Object}   req   the request stream
 * @param  {Object}   res   the response stream
 * @param  {Object}   job   the job being initialized
 * @param  {Function} next  continue to next middleware
 */
module.exports = function (req, res, job, next) {
  job.logger?.verbose('Initializing output fields');
  job.outputFields = job.outputFields || { added: [], removed: [] };

  var fieldsHeader = req.header('Output-Fields');

  if (!fieldsHeader) {
    job.logger?.verbose('Using default fields');
    return next();
  }

  job.logger?.verbose('Fields header: ' + fieldsHeader);
  var fields = fieldsHeader.split(',');

  for (var i = 0, l = fields.length; i < l; i++) {
    var field    = fields[i].trim();
    var operator = field.charAt(0);
    field        = field.substring(1).trim();

    if (!field) {
      return next(job.error(4012, 400));
    }

    switch (operator) {
    case '+':
      job.addOutputFields([field]);
      break;
    case '-':
      job.removeOutputFields([field]);
      break;
    default:
      return next(job.error(4013, 400));
    }
  }

  next();
};