86 lines
3.3 KiB
Markdown
86 lines
3.3 KiB
Markdown
[](http://badge.fury.io/js/express-queue)
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[](https://travis-ci.org/alykoshin/express-queue)
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[](https://coveralls.io/github/alykoshin/express-queue?branch=master)
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[](https://codeclimate.com/github/alykoshin/express-queue)
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[](https://inch-ci.org/github/alykoshin/express-queue)
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[](https://david-dm.org/alykoshin/express-queue#info=dependencies)
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[](https://david-dm.org/alykoshin/express-queue#info=devDependencies)
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[](https://snyk.io/test/github/alykoshin/express-queue)
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# express-queue
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Express middleware to limit a number of simultaneously processing requests using queue
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If you have different needs regarding the functionality, please add a [feature request](https://github.com/alykoshin/express-queue/issues).
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## Installation
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```sh
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npm install --save express-queue
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```
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## Usage
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```js
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var express = require('express');
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var queue = require('express-queue');
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var app = express();
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// Using queue middleware
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app.use(queue({ activeLimit: 2, queuedLimit: -1 }));
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// activeLimit - max request to process simultaneously
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// queuedLimit - max requests in queue until reject (-1 means do not reject)
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// rejectHandler - handler to call when queuedLimit is reached (see below)
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//
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// May be also:
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// app.get('/api', queue({ activeLimit: 2, queuedLimit: -1})
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```
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You can access MiniQueue object used internally. To get current queue length you may do following:
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```js
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const express = require('express');
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const expressQueue = require('../');
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const queueMw = expressQueue({ activeLimit: 2, queuedLimit: -1 });
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const app = express();
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app.use(queueMw);
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console.log(`queueLength: ${queueMw.queue.getLength()}`);
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```
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For more info on Queue object used refer to [npmjs.com/package/mini-queue](https://www.npmjs.com/package/mini-queue) package docs and/or [source code](https://github.com/alykoshin/mini-queue).
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## Reject handler
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If you set queuedLimit, when the queue is full, the middleware will reject any incoming request.
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The default handler will send a 503 status code, but you can setup your own handler with `rejectHandler` option, e.g.:
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```js
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const queueMw = expressQueue({ activeLimit: 2, queuedLimit: 6, rejectHandler: (req, res) => { res.sendStatus(500); } });
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```
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## Example
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Please, refer to `./examples/` directory for a working example.
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## Credits
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[Alexander](https://github.com/alykoshin/)
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# Links to package pages:
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[github.com](https://github.com/alykoshin/express-queue) [npmjs.com](https://www.npmjs.com/package/express-queue) [travis-ci.org](https://travis-ci.org/alykoshin/express-queue) [coveralls.io](https://coveralls.io/github/alykoshin/express-queue) [inch-ci.org](https://inch-ci.org/github/alykoshin/express-queue)
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## License
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MIT
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