Nginx Enable https on some pages only?

When on shared cPanel account (Apache), I can access my wordpress site with http or https, together. I also able to redirect WordPress front end https URLs to http without a plugin, but serve https only for wp-admin area.

But after migrating to vps and using nginx then after enable ssl, every http request will be redirected to https. I've modify the vhost conf following this blog post with no luck, http still redirected to https.
Nginx config for SSL WordPress admin only

Anyway to avoid https redirection?

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Here's my vhost conf.
I want to avoid http -> https redirection, when I type http urls.
Is it possible in nginx?

Code:

server {
listen 80;
server_name mydomain.com www.mydomain.com;
return 302 https://$server_name$request_uri;
}

server {
listen 443 ssl spdy;
server_name mydomain.com www.mydomain.com;

ssl_dhparam /usr/local/nginx/conf/ssl/mydomain.com/dhparam.pem;
ssl_certificate /usr/local/nginx/conf/ssl/mydomain.com/yourdomain_com.crt;
ssl_certificate_key /usr/local/nginx/conf/ssl/mydomain.com/yourdomain_com.key;
ssl_session_cache shared:SSL:10m;
ssl_session_timeout 10m;

ssl_protocols TLSv1 TLSv1.1 TLSv1.2;
add_header Alternate-Protocol 443:npn-spdy/3;
ssl_buffer_size 1400;
ssl_session_tickets on;

enable ocsp stapling
resolver 8.8.8.8 8.8.4.4 valid=10m;
resolver_timeout 10s;
ssl_stapling on;
ssl_stapling_verify on;
ssl_trusted_certificate /usr/local/nginx/conf/ssl/mydomain.com/mydomain.com-trusted.crt;

 

Thanks George,
It worked by duplicating all lines from port 80 server block to port 443 + add some ssl config, it's good right?