| /* |
| * Copyright (c) 2014-2017 BSI Business Systems Integration AG. |
| * All rights reserved. This program and the accompanying materials |
| * are made available under the terms of the Eclipse Public License v1.0 |
| * which accompanies this distribution, and is available at |
| * http://www.eclipse.org/legal/epl-v10.html |
| * |
| * Contributors: |
| * BSI Business Systems Integration AG - initial API and implementation |
| */ |
| import {strings} from '../index'; |
| |
| export default class ResponseQueue { |
| |
| constructor(session) { |
| this.session = session; |
| this.queue = []; |
| this.lastProcessedSequenceNo = 0; |
| this.nextExpectedSequenceNo = 1; |
| |
| this.force = false; |
| this.forceTimeoutId = null; |
| } |
| |
| static FORCE_TIMEOUT = 10 * 1000; // in ms |
| |
| add(response) { |
| var sequenceNo = response && response['#']; |
| |
| // Ignore responses that were already processed (duplicate detection) |
| if (sequenceNo && sequenceNo <= this.lastProcessedSequenceNo) { |
| return; |
| } |
| |
| // "Fast-forward" the expected sequence no. when a combined response is received |
| if (sequenceNo && response.combined) { |
| this.lastProcessedSequenceNo = Math.max(sequenceNo - 1, this.lastProcessedSequenceNo); |
| this.nextExpectedSequenceNo = Math.max(sequenceNo, this.nextExpectedSequenceNo); |
| } |
| |
| if (!sequenceNo || this.queue.length === 0) { // Handle messages without sequenceNo in the order they were received |
| this.queue.push(response); |
| } else { |
| // Insert at correct position (ascending order) |
| var newQueue = []; |
| var responseToInsert = response; |
| for (var i = 0; i < this.queue.length; i++) { |
| var el = this.queue[i]; |
| if (el['#']) { |
| if (responseToInsert && el['#'] > sequenceNo) { |
| // insert at position |
| newQueue.push(response); |
| responseToInsert = null; |
| } |
| if (el['#'] <= this.lastProcessedSequenceNo) { |
| // skip obsolete elements (may happen when a combined response is added to the queue) |
| continue; |
| } |
| } |
| newQueue.push(el); |
| } |
| if (responseToInsert) { |
| // no element with bigger seqNo found -> insert as last element |
| newQueue.push(responseToInsert); |
| } |
| this.queue = newQueue; |
| } |
| } |
| |
| process(response) { |
| if (response) { |
| this.add(response); |
| } |
| |
| // Process the queue in ascending order |
| var responseSuccess = true; |
| var missingResponse = false; |
| var nonProcessedResponses = []; |
| for (var i = 0; i < this.queue.length; i++) { |
| var el = this.queue[i]; |
| var sequenceNo = el['#']; |
| |
| // For elements with a sequence number, check if they are in the expected order |
| if (sequenceNo) { |
| if (this.nextExpectedSequenceNo && !this.force && !missingResponse) { |
| missingResponse = (this.nextExpectedSequenceNo !== sequenceNo); |
| } |
| if (missingResponse) { |
| // Sequence is not complete, process those messages later |
| nonProcessedResponses.push(el); |
| continue; |
| } |
| } |
| |
| // Handle the element |
| var success = this.session.processJsonResponseInternal(el); |
| // Only return success value of the response that was passed to the process() call |
| if (response && el === response) { |
| responseSuccess = success; |
| } |
| |
| // Update the expected next sequenceNo |
| if (sequenceNo) { |
| this.lastProcessedSequenceNo = sequenceNo; |
| this.nextExpectedSequenceNo = sequenceNo + 1; |
| } |
| } |
| // Keep non-processed events (because they are not in sequence) in the queue |
| this.queue = nonProcessedResponses; |
| |
| this._checkTimeout(); |
| |
| return responseSuccess; |
| } |
| |
| size() { |
| return this.queue.length; |
| } |
| |
| _checkTimeout() { |
| // If there are non-processed elements, schedule a job that forces the processing of those |
| // elements after a certain timeout to prevent the "blocked forever syndrome" if a response |
| // was lost on the network. |
| if (this.queue.length === 0) { |
| clearTimeout(this.forceTimeoutId); |
| this.forceTimeoutId = null; |
| } else if (!this.forceTimeoutId) { |
| this.forceTimeoutId = setTimeout(function() { |
| try { |
| var s = '['; |
| for (var i = 0; i < this.queue.length; i++) { |
| if (i > 0) { |
| s += ', '; |
| } |
| s += (strings.box('#', this.queue[i]['#']) || '<none>'); |
| } |
| s += ']'; |
| this.session.sendLogRequest('Expected response #' + this.nextExpectedSequenceNo + ' still missing after ' + |
| ResponseQueue.FORCE_TIMEOUT + ' ms. Forcing response queue to process ' + this.size() + ' elements: ' + s); |
| } catch (error) { |
| // nop |
| } |
| this.force = true; |
| try { |
| this.process(); |
| } finally { |
| this.force = false; |
| this.forceTimeoutId = null; |
| } |
| }.bind(this), ResponseQueue.FORCE_TIMEOUT); |
| } |
| } |
| |
| prepareRequest(request) { |
| request['#ACK'] = this.lastProcessedSequenceNo; |
| } |
| |
| prepareHttpRequest(ajaxOptions) { |
| ajaxOptions.headers = ajaxOptions.headers || {}; |
| ajaxOptions.headers['X-Scout-#ACK'] = this.lastProcessedSequenceNo; |
| } |
| } |