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https://github.com/advplyr/audiobookshelf.git
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08250e266e
This patch implements [X-Accel](https://www.nginx.com/resources/wiki/start/topics/examples/x-accel/) redirect headers as an optional way for offloading static file delivery from Express to Nginx, which is far better optimized for static file delivery. This provides a really easy to configure way for getting a huge performance boost over delivering all files through Audiobookshelf. How it works ------------ The way this works is basically that Audiobookshelf gets an HTTP request for delivering a static file (let's say an audiobook). It will first check the user is authorized and then convert the API path to a local file path. Now, instead of reading and delivering the file, Audiobookshelf will return just the HTTP header with an additional `X-Accel-Redirect` pointing to the file location on the file syste. This header is picked up by Nginx which will then deliver the file. Configuration ------------- The configuration for this is very simple. You need to run Nginx as reverse proxy and it must have access to your Audiobookshelf data folder. You then configure Audiobookshelf to use X-Accel by setting `USE_X_ACCEL=/protected`. The path is the internal redirect path used by Nginx. In the Nginx configuration you then configure this location and map it to the storage area to serve like this: ``` location /protected/ { internal; alias /; } ``` That's all. Impact ------ I just did a very simple performance test, downloading a 1170620819 bytes large audiobook file from another machine on the same network like this, using `time -p` to measure how log the process took: ```sh URL='https://url to audiobook…' for i in `seq 1 50` do echo "$i" curl -s -o /dev/null "${URL}" done ``` This sequential test with 50 iterations and without x-accel resulted in: ``` real 413.42 user 197.11 sys 82.04 ``` That is an average download speed of about 1080 MBit/s. With X-Accel enabled, serving the files through Nginx, the same test yielded the following results: ``` real 200.37 user 86.95 sys 29.79 ``` That is an average download speed of about 2229 MBit/s, more than doubling the previous speed. I have also run the same test with 4 parallel processes and 25 downloads each. Without x-accel, that test resulted in: ``` real 364.89 user 273.09 sys 112.75 ``` That is an average speed of about 2448 MBit/s. With X-Accel enabled, the parallel test also shows a significant speedup: ``` real 167.19 user 195.62 sys 78.61 ``` That is an average speed of about 5342 MBit/s. While doing that, I also peaked at the system load which was a bit lower when using X-Accel. Even though the system was delivering far more data. But I just looked at the `load1` values and did not build a proper test for that. That means, I cant provide any definitive data. Supported Media --------------- The current implementation works for audio files and book covers. There are other media files which would benefit from this mechanism like feed covers or author pictures. But that's something for a future developer ;-)
42 lines
1.4 KiB
JavaScript
42 lines
1.4 KiB
JavaScript
const express = require('express')
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const Path = require('path')
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const Logger = require('../Logger')
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const { getAudioMimeTypeFromExtname } = require('../utils/fileUtils')
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class StaticRouter {
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constructor(db) {
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this.db = db
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this.router = express()
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this.init()
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}
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init() {
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// Library Item static file routes
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this.router.get('/item/:id/*', (req, res) => {
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const item = this.db.libraryItems.find(ab => ab.id === req.params.id)
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if (!item) return res.status(404).send('Item not found with id ' + req.params.id)
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const remainingPath = req.params['0']
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const fullPath = item.isFile ? item.path : Path.join(item.path, remainingPath)
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// Allow reverse proxy to serve files directly
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// See: https://www.nginx.com/resources/wiki/start/topics/examples/x-accel/
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if (global.XAccel) {
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Logger.debug(`Use X-Accel to serve static file ${fullPath}`)
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return res.status(204).header({'X-Accel-Redirect': global.XAccel + fullPath}).send()
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}
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var opts = {}
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// Express does not set the correct mimetype for m4b files so use our defined mimetypes if available
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const audioMimeType = getAudioMimeTypeFromExtname(Path.extname(fullPath))
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if (audioMimeType) {
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opts = { headers: { 'Content-Type': audioMimeType } }
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}
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res.sendFile(fullPath, opts)
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})
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}
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}
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module.exports = StaticRouter |