45 lines
1.4 KiB
JavaScript
45 lines
1.4 KiB
JavaScript
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const queue = require('queue-async');
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const _ = require('underscore');
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/**
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* Convenient object to do async batch processing, and don't continue until all items have successfully finished.
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* In case of error it will fail immediately.
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*
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* Example usage:
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* var batchProcess = require('../common/batch_process_items');
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* batchProcess({
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* items: [ ... ],
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* done: function () {
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* this.close();
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* },
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* fail: function (jqXHR, errorType, e) {
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* this._errorMsg = 'Server response: '+ jqXHR.responseText;
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* this.render();
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* }
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* });
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*
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* @param opts {Object}
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* howManyInParallel: {Number}
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* items: {Array} each item will be passed to processItem(item, ...
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* processItem: {Function} given an item and a callback, should call callback() for success case, or callback(error) if something failed.
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* fail: {Function}
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* done: {Function} called if all items
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*/
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module.exports = function (opts) {
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var q = queue(opts.howManyInParallel);
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_.each(opts.items, function (item) {
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q.defer(function (callback) {
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opts.processItem(item, callback);
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});
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});
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q.awaitAll(function (error/*, result1, ..., resultN */) {
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// error and results contains outcome of the jqXHR requests above, see http://api.jquery.com/jQuery.ajax/#jqXHR
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if (error) {
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opts.fail(error);
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} else {
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opts.done();
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}
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});
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};
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