☰

为什么 SPDY 会破坏 Nginx 1.4.3 中的‘Vary:Accept-Encoding’？

tag-icon • tag-icon nginx ssl web-server http-headers spdy
为什么 SPDY 会破坏 Nginx 1.4.3 中的‘Vary:Accept-Encoding’？

我已经使用 SPDY 模块从源代码编译了 Nginx 1.4.3。

然而，当启用 SPDY 时，它似乎会破坏我的“Vary：Accept-Encoding”标头。

我的Nginx配置：

./configure
--conf-path=/etc/nginx/nginx.conf
--pid-path=/var/run/nginx.pid
--error-log-path=/var/log/nginx/error.log
--http-proxy-temp-path=/var/cache/nginx/proxy_temp
--http-fastcgi-temp-path=/var/cache/nginx/fastcgi_temp
--http-uwsgi-temp-path=/var/cache/nginx/uwsgi_temp
--http-scgi-temp-path=/var/cache/nginx/scgi_temp
--http-log-path=/var/log/nginx/access.log
--with-http_ssl_module --prefix=/usr
--add-module=./nginx-sticky-module-1.1
--add-module=./headers-more-nginx-module-0.23
--with-http_spdy_module

我的“nginx.conf”文件：

user  nginx;
worker_processes  1;

error_log  /var/log/nginx/error.log warn;
pid        /var/run/nginx.pid;


events {
    worker_connections  1024;
}


http {
    include       /etc/nginx/mime.types;
    default_type  application/octet-stream;

    log_format  main  '$remote_addr - $remote_user [$time_local] "$request" '
                      '$status $body_bytes_sent "$http_referer" '
                      '"$http_user_agent" "$http_x_forwarded_for"';

    access_log  /var/log/nginx/access.log  main;

    sendfile        on;
    #tcp_nopush     on;

    keepalive_timeout  65;

    #Compression Settings
    gzip on;
    gzip_http_version 1.0;
    gzip_comp_level 2;
    gzip_proxied any;
    gzip_min_length  1100;
    gzip_buffers 16 8k;
    gzip_types text/plain text/css application/x-javascript text/xml application/xml application/xml+rss text/javascript image/svg+xml;
    # Some version of IE 6 don't handle compression well on some mime-types, 
    # so just disable for them
    gzip_disable "MSIE [1-6].(?!.*SV1)";
    # Set a vary header so downstream proxies don't send cached gzipped 
    # content to IE6
    gzip_vary on;

    proxy_cache_path /var/www/nginx_cache levels=1:2 keys_zone=qnx-cache:10m inactive=24h max_size=1g;
    proxy_temp_path /var/www/nginx_cache/tmp;

    server_tokens off;

    include /etc/nginx/conf.d/*.conf;

    map $geo $mapping {
        default default;
        US US;
        DE DE;
    CA CA;
    GB GB;
    }
    geo $geo {
        default default;
        include geo.conf;
    }
    upstream default.backend {
#   sticky;
        server 192.168.0.5:8080;
        server 192.168.0.6:8080;
        server 192.168.0.7:8080;
    }
    upstream mysite.backend {
        sticky name=servIDTrack hash=sha1;
        server 192.168.0.5:8080 weight=10 max_fails=3 fail_timeout=10s;
        server 192.168.0.6:8080 weight=10 max_fails=3 fail_timeout=10s;
        server 192.168.0.7:8080 weight=10 max_fails=3 fail_timeout=10s;
    }
server {
        listen      80;
        server_name secure.mysite.com;
        return 301 https://$server_name$request_uri;
    }
server {
        listen 443 ssl;
        server_name secure.mysite.com;
        more_set_headers    "Server: X-nginx/v1.1 [LB01]";

        ssl_certificate     /etc/nginx/ssl/secure_mysite_com_ssl.cert;
        ssl_certificate_key /etc/nginx/ssl/secure_mysite_com_ssl.key;

        ssl_protocols           SSLv3 TLSv1 TLSv1.1 TLSv1.2;
#       ssl_ciphers             RC4:HIGH:!aNULL:!MD5;
        ssl_ciphers         ECDHE-ECDSA-AES256-GCM-SHA384:ECDHE-RSA-AES256-GCM-SHA384:ECDHE-ECDSA-AES256-SHA384:ECDHE-RSA-AES256-SHA384:ECDHE-ECDSA-AES128-GCM-SHA256:ECDHE-RSA-AES128-GCM-SHA256:ECDHE-ECDSA-AES128-SHA256:ECDHE-RSA-AES128-SHA256:ECDHE-ECDSA-RC4-SHA:ECDHE-RSA-RC4-SHA:ECDH-ECDSA-RC4-SHA:ECDH-RSA-RC4-SHA:ECDHE-RSA-AES256-SHA:RC4-SHA;
        ssl_prefer_server_ciphers on;
        keepalive_timeout       120;
        ssl_session_cache       builtin:1000 shared:SSL:10m;
        ssl_session_timeout     10m;

        location / {
            proxy_pass http://mysite.backend;
            proxy_set_header        Host            $host;
            proxy_set_header        X-Real-IP       $remote_addr;
            proxy_set_header        X-Forwarded-For $proxy_add_x_forwarded_for;
            proxy_redirect          off;
            proxy_http_version      1.1;

            add_header Strict-Transport-Security "max-age=31556926; includeSubdomains";

    # Cache
                proxy_cache qnx-cache;
                proxy_cache_valid  200 301 302  120m;
                proxy_cache_valid 404 1m;
                add_header X-Cache-Status $upstream_cache_status;
                proxy_cache_key "$scheme$host$request_uri";

        }
    }
}

启用/禁用 SPDY 后的标头结果：

url: mypage.php (SPDY enabled)

HTTP/1.1 200 OK
cache-control: no-store, no-cache, must-revalidate, post-check=0, pre-check=0
content-encoding: gzip
content-type: text/html; charset=utf-8
date: Wed, 20 Nov 2013 13:39:30 GMT
expires: Thu, 19 Nov 1981 08:52:00 GMT
pragma: no-cache
server: X-nginx/v1.1 [LB01]
status: 200
strict-transport-security: max-age=31556926; includeSubdomains
version: HTTP/1.1
x-cache-status: MISS

url: mypage.php (SPDY disabled)

HTTP/1.1 200 OK
Date: Wed, 20 Nov 2013 13:45:00 GMT
Content-Type: text/html; charset=utf-8
Transfer-Encoding: chunked
Connection: keep-alive
Vary: Accept-Encoding
Expires: Thu, 19 Nov 1981 08:52:00 GMT
Cache-Control: no-store, no-cache, must-revalidate, post-check=0, pre-check=0
Pragma: no-cache
Server: X-nginx/v1.1 [LB01]
Strict-Transport-Security: max-age=31556926; includeSubdomains
X-Cache-Status: MISS
Content-Encoding: gzip

url: mystyle.css (SPDY enabled)

HTTP/1.1 200 OK
date: Wed, 20 Nov 2013 12:53:49 GMT
content-encoding: gzip
last-modified: Mon, 18 Nov 2013 22:09:32 GMT
server: X-nginx/v1.1 [LB01]
x-cache-status: HIT
strict-transport-security: max-age=31556926; includeSubdomains
content-type: text/css
status: 304
expires: Wed, 18 Dec 2013 22:42:35 GMT
cache-control: max-age=2592000
version: HTTP/1.1

url: mystyle.css (SPDY disabled)

HTTP/1.1 200 OK
Date: Wed, 20 Nov 2013 13:45:01 GMT
Content-Type: text/css
Transfer-Encoding: chunked
Connection: keep-alive
Vary: Accept-Encoding
Last-Modified: Mon, 18 Nov 2013 22:09:32 GMT
Cache-Control: max-age=2592000
Expires: Wed, 18 Dec 2013 22:10:13 GMT
Server: X-nginx/v1.1 [LB01]
Strict-Transport-Security: max-age=31556926; includeSubdomains
X-Cache-Status: HIT
Content-Encoding: gzip

如您所见，当启用 SPDY 时，Vary: Accept-Encoding标题就会消失。

nginx.conf这是我的配置方式的问题吗？

答案1

SPDY（和 HTTP/2.0）要求用户代理支持压缩，这使得标Vary: Accept-Encoding头毫无用处。这就是 nginx 删除标头的原因。

答案2

这可能是也可能不是一个错误，但由于 SPDY 始终使用压缩，并且目前没有 SPDY 正向代理（因为 SPDY 始终使用 TLS），因此 Vary 标头毫无用处。Vary 仅供代理用于确定是否发送压缩或未压缩的内容

基本上，如果连接系统支持 SPDY，它也支持 gzip 压缩内容，因此无需在 Vary 标头上浪费字节。至少一些支持 SPDY 的大型网站正在这样做。请参阅这一页了解更多详情。

理论上，将来可能会有公司使用不支持 HTTP 压缩的旧版浏览器，但我真的希望不会。即使有，如果客户端没有发送“Accept-Encoding: gzip”标头，代理也可以以较低的开销即时解压缩。

答案3

SPDY 和 HTTP/2 有自己专用的报头压缩机制。标准这意味着浏览器必须支持数据压缩才能使用 SPDY 或 HTTP/2，这使得添加 Vary 标头变得多余。在这种情况下，排除 Vary 标头还可以在每个请求消息中节省几个字节。

对此有更详细的解释这里。

相关内容