Problem with proxy_set_header $ssl_client_cert

[Sergey Budnevitch]

On 25  Feb2013, at 18:37 , Lynoure <nginx-forum at nginx.us> wrote:

>> The $ssl_client_cert variable abuses header continuation, and this
>> doesn't work with many http servers (including nginx itself).
> 
> Noticed that with spray-can. 
> 
>> There should be more portable way to pass client certificate to an
>> upstream server.
> 
> Is there already, or is there one in plans? Any known workarounds? Encoding
> and decoding the $ssl_client_cert somehow? (I'm really new to nginx.)

You could hack ngx_ssl_get_certificate() function to get certificate in one line,
or there is an ugly, but possible way to remove limited number of newline
characters from variable with map directive:

map $ssl_client_raw_cert $a {
"~^(-.*-\n)(?<1st>[^\n]+)\n((?<b>[^\n]+)\n)?((?<c>[^\n]+)\n)?((?<d>[^\n]+)\n)?((?<e>[^\n]+)\n)?((?<f>[^\n]+)\n)?((?<g>[^\n]+)\n)?((?<h>[^\n]+)\n)?((?<i>[^\n]+)\n)?((?<j>[^\n]+)\n)?((?<k>[^\n]+)\n)?((?<l>[^\n]+)\n)?((?<m>[^\n]+)\n)?((?<n>[^\n]+)\n)?((?<o>[^\n]+)\n)?((?<p>[^\n]+)\n)?((?<q>[^\n]+)\n)?((?<r>[^\n]+)\n)?((?<s>[^\n]+)\n)?((?<t>[^\n]+)\n)?((?<v>[^\n]+)\n)?((?<u>[^\n]+)\n)?((?<w>[^\n]+)\n)?((?<x>[^\n]+)\n)?((?<y>[^\n]+)\n)?((?<z>[^\n]+)\n)?(-.*-)$" $1st;
}

server {
    location / {
        proxy_set_header X-cert $a$b$c$d$e$f$g$h$i$j$k$l$m$n$o$p$q$r$s$t$v$u$w$x$y$z;
        proxy_pass http://localhost:8000;
    }
}

Example works for up to 26 line certificate, you could extend it to reasonable number of lines.