Nginx with data compression on java applet

Hi ALL,

I am very new to nginx, and I found the nginx is the perfect tool for me
to do reverse-proxy while compressing the data. I have successfully
configured the proxy_pass and gzip configurations and it is working as I
expected in test environments.

We have web servers which streaming text data through java applet to the
end users. Nginx is act as a reverse-proxy for back-end web servers;
once the java applet loaded on the FireFox or IE browser it keep
receiving data without any issue. But the problem is those text data
won’t get compressed though text, images etc loaded to the browser get
compressed. I can compress data off the applet but once it send it to
java applet, won’t get compressed.

Here is my nginx.conf:

http {
include mime.types;
default_type application/octet-stream;
sendfile on;
keepalive_timeout 65;

compression

gzip on;
gzip_http_version 1.0;
gzip_comp_level 4;
gzip_proxied private;
gzip_min_length  1100;
gzip_buffers 16 8k;
gzip_types text/plain text/html text/css application/x-javascript \
    text/xml application/xml application/xml+rss text/javascript \
    image/gif image/jpeg image/png;
gzip_disable "MSIE [1-6].(?!.*SV1)";
gzip_vary on;
server {
    listen       80;
    server_name  localhost;


location / {
    proxy_pass         http://data.example.com/;
    proxy_redirect     off;

    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_max_temp_file_size 0;

    client_max_body_size       10m;
    client_body_buffer_size    128k;

    proxy_connect_timeout      90;
    proxy_send_timeout         90;
    proxy_read_timeout         90;

    proxy_buffer_size          4k;
    proxy_buffers              4 32k;
    proxy_busy_buffers_size    64k;
    proxy_temp_file_write_size 64k;

    }
    error_page   500 502 503 504  /50x.html;
    location = /50x.html {
        root   /usr/local/www/nginx-dist;
    }

}

I’m Running on FreeBSD7.1 and I googled such scenario but no luck. To
get this done where do I have to looking in to…? Any advice is really
appreciated

Thanks in advance
Hirantha

My guess is that the Java applet isn’t telling the server that it can
accept
compressed content when it makes the requests to nginx. Try configuring
the
applet to tell the server to send gzipped content. Note that it’s
possible
that Java applets may not be able to handle compressed content at all,
in
which case it’s a good thing that nginx is not making that assumption.

You should be able to watch the requests with Firebug in Firefox to see
the
Accept-Encoding header. If you can’t see the Java applet requests with
Firebug (or another Firefox headers extension) you can use Ethereal or a
command-line tool on the client or server.

See section 14.3 of the W3’s HTTP/1.1 Header Field Definitions page for
more
info:
http://www.w3.org/Protocols/rfc2616/rfc2616-sec14.html

On Sat, Mar 14, 2009 at 02:11:38AM +0530, hirantha wrote:

receiving data without any issue. But the problem is those text data
won’t get compressed though text, images etc loaded to the browser get
compressed. I can compress data off the applet but once it send it to
java applet, won’t get compressed.

It seems that java applet does not send the “Accept-Encoding: gzip”
request header.

BTW why do you compress image/gif image/jpeg image/png ?
This is just waste of CPU time.

Thanks guys for the replies…

Igor S. wrote:

end users. Nginx is act as a reverse-proxy for back-end web servers;
once the java applet loaded on the FireFox or IE browser it keep
receiving data without any issue. But the problem is those text data
won’t get compressed though text, images etc loaded to the browser get
compressed. I can compress data off the applet but once it send it to
java applet, won’t get compressed.

It seems that java applet does not send the “Accept-Encoding: gzip”
request header.

I ran Wireshark to analyze the data on java applet and firefox browser
to check what type of header
request they send. Here are my findings.

From browser:
GET /mbr/ds.aspx?SID=1F5AAWQWQWSA1 HTTP/1.1
Host: data.example.com
User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.9.0.7)
Gecko/2009030503 Fedora/3.0.7-1.fc10
Firefox/3.0.7
Accept: text/html,application/xhtml+xml,application/xml;q=0.9,/;q=0.8
Accept-Language: en-us,en;q=0.5
Accept-Encoding: gzip,deflate
Accept-Charset: ISO-8859-1,utf-8;q=0.7,*;q=0.7
Keep-Alive: 300
Connection: keep-alive

From Java applet loaded from Firefox:
GET /sabb/GetUserParams.aspx?Y=BC672 HTTP/1.1
User-Agent: Java™ 2 SDK, Standard Edition v1.6.0_0 Java/1.6.0_0
Host: data.example.com
Accept: text/html, image/gif, image/jpeg, *; q=.2, /; q=.2
Connection: keep-alive

I think java applet don’t sends Accept-Encoding header to the server;
and this should be the
problem. I am not a java expert and the new question, is this possible
with a java applet set
Accept-Encoding request header…?

BTW why do you compress image/gif image/jpeg image/png ?
This is just waste of CPU time.

Yes, I have to avoid them, my concern is huge text data.

Any advice on the new question is really appreciated.

Regards
Hirantha

Depends on how the applet is written, I’d guess. Not sure though.
However,
if compression is very important and accepting gzipped content is not
possible with an applet, you could gzip the files beforehand so that the
files that are served are gzipped already (even though there’s no
Accept-Encoding header). This would of course require that the applet
decompress the text before processing, but at least you’d cut down on
your
network traffic…

Thanks guys,

It is working as expected…!

And thanks to nginx guys, this is amazing service.

Regards
Hirantha