将响应gzip压缩发送到未指定Accept-Encoding:gzip的客户端是一个bug吗?

Accept-Encoding: gzip ? 它是否违反了http规范?还是合法?

https://www.amazon.com 总是发送gzip压缩的内容,不管接受编码头是什么,作为一个简单的测试来确认:

$ curl https://www.amazon.com
Warning: Binary output can mess up your terminal. Use "--output -" to tell
Warning: curl to output it to your terminal anyway, or consider "--output
Warning: <FILE>" to save to a file.

$ curl https://www.amazon.com -I
HTTP/2 405
content-type: text/html; charset=UTF-8
server: Server
date: Sat, 03 Nov 2018 11:27:35 GMT
set-cookie: skin=noskin; path=/; domain=.amazon.com
strict-transport-security: max-age=47474747; includeSubDomains; preload
x-amz-id-1: 2M3HZHHA9J21D3MTHH4K
allow: POST, GET
vary: Accept-Encoding,User-Agent,X-Amazon-CDN-Cache
content-encoding: gzip
x-amz-rid: 2M3HZHHA9J21D3MTHH4K
x-frame-options: SAMEORIGIN
x-cache: Error from cloudfront
via: 1.1 1cc4305a3ce000ca199328864ca1c98e.cloudfront.net (CloudFront)
x-amz-cf-id: OKz61IdKmCBfC97pPg-zmDhQnJzK3THXL2iYwegU5EtDaRf6yjBGzw==

• curl抱怨它在这里接收二进制数据,因为它没有用HTML响应,而是gzip压缩的HTML,这是二进制数据。要实际查看html,请添加 --compressed 参数,它告诉curl添加标头 Accept-Encoding: gzip, deflate