How to save into variable proxy header response?

[google000]

Hello I'm using nginx as reverse proxy for some domain .. my configuration
for domain looks like that :

server
        {
                listen       80;
                server_name www.mydomain.com mydomain.com;
                index index.html index.htm index.php default.html
default.htm;
location / {
    proxy_buffering off;
    proxy_max_temp_file_size 0;
    proxy_pass http://www.domainresultget.com;
}}

response header from this domain "www.domainresultget.com" looks like that
..

HTTP/1.1 200 OK
CF-RAY: 11d864fce3900a9c-PRG
Connection: keep-alive
Content-Disposition: attachment; filename="filename_title_download.exe"
Content-Length: 351744
Content-Type: application/x-msdownload
Date: Sat, 19 Apr 2014 10:24:48 GMT
Server: nginx
X-Powered-By: PHP/5.3.3

I want to save filename title in to variable for future use ? I mean this
one "filename_title_download.exe" I want to save this in to variable.. Can
someone explain me how to do this ?

thank you so much, and sorry for my english.

Posted at Nginx Forum: http://forum.nginx.org/read.php?2,249402,249402#msg-249402