76 lines
2.1 KiB
JavaScript
76 lines
2.1 KiB
JavaScript
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'use strict';
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const debug = require('debug')('queue');
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const endMw = require('express-end');
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const MiniQueue = require('mini-queue');
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const expressQueueMw = function(config) {
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debug('Initializing: config:', config);
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const self = {};
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const rejectHandler = config.rejectHandler || defaultRejectHandler;
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self.jobQueue = new MiniQueue(config);
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// When any task has gone to `process` state,
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// wait for `end` event of `res` object (`job.data.res`)
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// then leave the `process` state
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self.jobQueue.on('process', function(job, done) {
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//job.data.res.removeAllListeners('end'); // Remove listener which was set in on(queued) event
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job.data.res.once('end', function() { // `end` event is sent on res.end() by `express-end` middleware package
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done();
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});
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job.data.next();
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});
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self.jobQueue.on('reject', function(job) {
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debug('Rejected ' + job.data.req.path);
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rejectHandler(job.data.req, job.data.res);
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});
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self.queueMw = function(req,res,next) {
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const data = { req: req, res: res, next: next };
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const job = self.jobQueue.createJob(data);
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// Set listeners for logging
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res.once('close', function() { job.log('resOnClose'); }); // Closed from remote end
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res.once('end', function() { job.log('resOnEnd'); }); // Sent on res.end() by express-end
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res.once('finish', function() { job.log('resOnFinish'); });
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// Handle disconnect from client while in queue
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res.once('close', function() {
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if (job.status === 'queue') {
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// Return HTTP 204 No Content
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// - it must not be sent as the connection is already close by Client
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job.data.res.status(204).end();
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self.jobQueue._cancelJob(job);
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}
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});
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};
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// merge `end` and `queue` middlewares
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const resultMw = function(req, res, next) {
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endMw(req, res, function () { // Inject res.end() handler to emit 'end' event
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self.queueMw(req, res, next); // Use this middleware
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});
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};
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// expose queue
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resultMw.queue = self.jobQueue;
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return resultMw;
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};
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function defaultRejectHandler(req, res) {
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res.status(503).send('Service Unavailable');
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}
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module.exports = expressQueueMw;
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