Brotli is a new open source compression algorithm, which has better performance than Gzip. After you enable Brotli compression, points of presence (POPs) compress resources before the resources are returned to clients. This reduces file sizes, accelerates file distribution, and reduces bandwidth consumption.
Background information
Compression can be implemented by using Gzip or Brotli. Intelligent compression uses Gzip to compress files. For more information about intelligent compression, see Configure Gzip compression.
You can use the Gzip compression or Brotli compression feature to compress the files only if the size of files on the origin server ranges from 1 KB to 10 MB. Files that are smaller than 1 KB or larger than 10 MB are not compressed.
Brotli compression supports the following formats: text/xml, text/plain, text/css, application/javascript, application/x-javascript, application/rss+xml, text/javascript, image/tiff, image/svg+xml, application/json, and application/xml.
If a response from the origin server includes the
Content-Encoding: brresponse header, the resources that are returned to the client are Brotli-compressed.If a request includes the
Accept-Encoding: brrequest header, the client expects the requested resources to be Brotli-compressed.
Usage notes
When Alibaba Cloud CDN compresses static files, the MD5 values of the files are changed. If files on the origin server have MD5 verification enabled, disable Gzip compression and Brotli compression.
If compression is enabled on the origin server and the response from the origin server carries
content_encoding, compression on POPs does not take effect.If both Brotli compression and Gzip compression are enabled, and the
Accept-Encodingrequest header includes bothbrandgzip, only Brotli compression takes effect.If both HTML optimization and Intelligent or Brotli compression are enabled, HTML optimization does not take effect. Alibaba Cloud CDN only compresses files.
Brotli is not compatible with all browsers. You can query whether a browser is compatible with Brotli as needed.
Common types of image files such as PNG, JPG, and JPEG and video files such as MP4, AVI, and WMV are already compressed. Gzip compression and Brotli compression do not take effect for these files. We recommend that you disable compression. If you want to reduce the size of image files, you can use the image editing feature. For more information, see Image editing overview. If you want to reduce the size of video files, you can use the video transcoding feature. For more information, see Audio and video transcoding. Both image editing and video transcoding reduce image resolution.
Procedure
Log on to the Alibaba Cloud CDN console.
In the left-side navigation pane, click Domain Names.
On the Domain Names page, find the domain name that you want to manage and click Manage in the Actions column.
In the left-side navigation pane of the domain name, click Optimization.
In the Brotli Compression section, turn on Brotli Compression and configure the parameters based on your business requirements.
After you enable Brotli compression, you can compare the format of a file before and after compression is performed. If the file name extension is .br, the file is compressed.
