76 lines
2.2 KiB
JavaScript
76 lines
2.2 KiB
JavaScript
this.recline = this.recline || {};
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this.recline.Backend = this.recline.Backend || {};
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this.recline.Backend.DataProxy = this.recline.Backend.DataProxy || {};
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(function(my) {
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my.__type__ = 'dataproxy';
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// URL for the dataproxy
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my.dataproxy_url = 'http://jsonpdataproxy.appspot.com';
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// Timeout for dataproxy (after this time if no response we error)
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// Needed because use JSONP so do not receive e.g. 500 errors
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my.timeout = 5000;
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// use either jQuery or Underscore Deferred depending on what is available
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var Deferred = _.isUndefined(this.jQuery) ? _.Deferred : jQuery.Deferred;
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// ## load
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//
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// Load data from a URL via the [DataProxy](http://github.com/okfn/dataproxy).
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//
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// Returns array of field names and array of arrays for records
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my.fetch = function(dataset) {
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var data = {
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url: dataset.url,
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'max-results': dataset.size || dataset.rows || 1000,
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type: dataset.format || ''
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};
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var jqxhr = jQuery.ajax({
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url: my.dataproxy_url,
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data: data,
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dataType: 'jsonp'
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});
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var dfd = new Deferred();
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_wrapInTimeout(jqxhr).done(function(results) {
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if (results.error) {
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dfd.reject(results.error);
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}
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dfd.resolve({
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records: results.data,
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fields: results.fields,
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useMemoryStore: true
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});
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})
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.fail(function(arguments) {
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dfd.reject(arguments);
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});
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return dfd.promise();
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};
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// ## _wrapInTimeout
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//
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// Convenience method providing a crude way to catch backend errors on JSONP calls.
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// Many of backends use JSONP and so will not get error messages and this is
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// a crude way to catch those errors.
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var _wrapInTimeout = function(ourFunction) {
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var dfd = new Deferred();
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var timer = setTimeout(function() {
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dfd.reject({
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message: 'Request Error: Backend did not respond after ' + (my.timeout / 1000) + ' seconds'
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});
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}, my.timeout);
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ourFunction.done(function(arguments) {
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clearTimeout(timer);
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dfd.resolve(arguments);
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})
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.fail(function(arguments) {
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clearTimeout(timer);
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dfd.reject(arguments);
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})
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;
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return dfd.promise();
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}
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}(this.recline.Backend.DataProxy));
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