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backend.dataproxy.js

this.recline = this.recline || {};
this.recline.Backend = this.recline.Backend || {};
this.recline.Backend.DataProxy = this.recline.Backend.DataProxy || {};

(function(my) {
  my.__type__ = 'dataproxy';

URL for the dataproxy

  my.dataproxy_url = '//jsonpdataproxy.appspot.com';

Timeout for dataproxy (after this time if no response we error) Needed because use JSONP so do not receive e.g. 500 errors

  my.timeout = 5000;

  

use either jQuery or Underscore Deferred depending on what is available

  var Deferred = _.isUndefined(this.jQuery) ? _.Deferred : jQuery.Deferred;

load

Load data from a URL via the DataProxy.

Returns array of field names and array of arrays for records

  my.fetch = function(dataset) {
    var data = {
      url: dataset.url,
      'max-results':  dataset.size || dataset.rows || 1000,
      type: dataset.format || ''
    };
    var jqxhr = jQuery.ajax({
      url: my.dataproxy_url,
      data: data,
      dataType: 'jsonp'
    });
    var dfd = new Deferred();
    _wrapInTimeout(jqxhr).done(function(results) {
      if (results.error) {
        dfd.reject(results.error);
      }

      dfd.resolve({
        records: results.data,
        fields: results.fields,
        useMemoryStore: true
      });
    })
    .fail(function(args) {
      dfd.reject(args);
    });
    return dfd.promise();
  };

_wrapInTimeout

Convenience method providing a crude way to catch backend errors on JSONP calls. Many of backends use JSONP and so will not get error messages and this is a crude way to catch those errors.

  var _wrapInTimeout = function(ourFunction) {
    var dfd = new Deferred();
    var timer = setTimeout(function() {
      dfd.reject({
        message: 'Request Error: Backend did not respond after ' + (my.timeout / 1000) + ' seconds'
      });
    }, my.timeout);
    ourFunction.done(function(args) {
        clearTimeout(timer);
        dfd.resolve(args);
      })
      .fail(function(args) {
        clearTimeout(timer);
        dfd.reject(args);
      })
      ;
    return dfd.promise();
  };

}(this.recline.Backend.DataProxy));