I am a new nginx user and I would like to redirect all mobile / smart phone users from www.example.com to m.example.com domain. How do I detect a mobile phone browser in nginx?

How do I redirect all mobile users to sub-domain using regex based rules?

And How can I automatically redirects visitors on mobile devices to its mobile version at http://m.example.com/ and also allow mobile devices to the desktop website at www.example.com if visiting via http://www.example.com/?desktop=true?

 

You can easily redirect all mobile users using nginx as follows:

m.example.com – Mobile domain name. Make sure app is configured to display same page as served on www.example.com

All desktop clients need to use www.example.com. However, m.example.com i.e. all mobile phone user can browser desktop version if visiting via www.example.com/?desktop=true

Make sure line Disallow: /*? added to /robots.txt on www.example.com

/robots.txt – It is a good idea to block all bots on m.example.com. This ensures that mobile users will see lightweight page; but all bots refer to your main site. This is SEO feature. Sample /robots.txt for m.example.com

User-agent: *

Disallow: /

From the robots.org page:

The “User-agent: *” means this section applies to all robots. The “Disallow: /” tells the robot that it should not visit any pages on the site. Bad robots can ignore your /robots.txt.

Especially malware robots that scan the web for security vulnerabilities, and email address harvesters used by spammers will pay no attention. However, good robots such as Googlebot will follow your /robots.txt file.

Sample /robots.txt for www.example.com:

User-agent: *

Disallow: /*?

Nginx configurations

Edit the nginx.conf file and append the following after server directive:

set $mobile_rewrite do_not_perform;

 

chi http_user_agent for mobile / smart phones ##

if ($http_user_agent ~*  (android|bb\d+|meego).+mobile|avantgo|bada\/|blackberry|blazer|compal|elaine|fennec|hiptop|iemobile|ip(hone|od)|iris|kindle|lge |maemo|midp|mmp|netfront|opera m(ob|in)i|palm( os)?|phone|p(ixi|re)\/|plucker|pocket|psp|series(4|6)0|symbian|treo|up\.(browser|link)|vodafone|wap|windows (ce|phone)|xda|xiino ) {

set $mobile_rewrite perform;

}

 

if ($http_user_agent ~*  ^(1207|6310|6590|3gso|4thp|50[1-6]i|770s|802s|a wa|abac|ac(er|oo|s\-)|ai(ko|rn)|al(av|ca|co)|amoi|an(ex|ny|yw)|aptu|ar(ch|go)|as(te|us)|attw|au(di|\-m|r |s )|avan|be(ck|ll|nq)|bi(lb|rd)|bl(ac|az)|br(e|v)w|bumb|bw\-(n|u)|c55\/|capi|ccwa|cdm\-|cell|chtm|cldc|cmd\-|co(mp|nd)|craw|da(it|ll|ng)|dbte|dc\-s|devi|dica|dmob|do(c|p)o|ds(12|\-d)|el(49|ai)|em(l2|ul)|er(ic|k0)|esl8|ez([4-7]0|os|wa|ze)|fetc|fly(\-|_)|g1 u|g560|gene|gf\-5|g\-mo|go(\.w|od)|gr(ad|un)|haie|hcit|hd\-(m|p|t)|hei\-|hi(pt|ta)|hp( i|ip)|hs\-c|ht(c(\-| |_|a|g|p|s|t)|tp)|hu(aw|tc)|i\-(20|go|ma)|i230|iac( |\-|\/)|ibro|idea|ig01|ikom|im1k|inno|ipaq|iris|ja(t|v)a|jbro|jemu|jigs|kddi|keji|kgt( |\/)|klon|kpt |kwc\-|kyo(c|k)|le(no|xi)|lg( g|\/(k|l|u)|50|54|\-[a-w])|libw|lynx|m1\-w|m3ga|m50\/|ma(te|ui|xo)|mc(01|21|ca)|m\-cr|me(rc|ri)|mi(o8|oa|ts)|mmef|mo(01|02|bi|de|do|t(\-| |o|v)|zz)|mt(50|p1|v )|mwbp|mywa|n10[0-2]|n20[2-3]|n30(0|2)|n50(0|2|5)|n7(0(0|1)|10)|ne((c|m)\-|on|tf|wf|wg|wt)|nok(6|i)|nzph|o2im|op(ti|wv)|oran|owg1|p800|pan(a|d|t)|pdxg|pg(13|\-([1-8]|c))|phil|pire|pl(ay|uc)|pn\-2|po(ck|rt|se)|prox|psio|pt\-g|qa\-a|qc(07|12|21|32|60|\-[2-7]|i\-)|qtek|r380|r600|raks|rim9|ro(ve|zo)|s55\/|sa(ge|ma|mm|ms|ny|va)|sc(01|h\-|oo|p\-)|sdk\/|se(c(\-|0|1)|47|mc|nd|ri)|sgh\-|shar|sie(\-|m)|sk\-0|sl(45|id)|sm(al|ar|b3|it|t5)|so(ft|ny)|sp(01|h\-|v\-|v )|sy(01|mb)|t2(18|50)|t6(00|10|18)|ta(gt|lk)|tcl\-|tdg\-|tel(i|m)|tim\-|t\-mo|to(pl|sh)|ts(70|m\-|m3|m5)|tx\-9|up(\.b|g1|si)|utst|v400|v750|veri|vi(rg|te)|vk(40|5[0-3]|\-v)|vm40|voda|vulc|vx(52|53|60|61|70|80|81|83|85|98)|w3c(\-| )|webc|whit|wi(g |nc|nw)|wmlb|wonu|x700|yas\-|your|zeto|zte\-) ) {

set $mobile_rewrite perform;

}

 

redirect to m.example.com ##

if ($mobile_rewrite = perform) {

rewrite ^ http://m.example.com$request_uri? redirect;

break;

}

Adding exceptions

You can allow user to browse and view desktop version of your site if url has www.example.com/?desktop=true. You can set cookie as follows:

set $force_dt_cookie    ;

 

if ($args ~  desktop=true ) {

set $mobile_rewrite do_not_perform;

set $force_dt_cookie   desktop=true ;

}

 

add_header Set-Cookie $force_dt_cookie;

 

 

if ($http_cookie ~  desktop=true ) {

set $mobile_rewrite do_not_perform;

}

Save and close the file. Restart or reload the nginx server, enter:

# /usr/sbin/nginx -s reload

 

OR

# /etc/init.d/nginx reload

Test it

Use the curl command as follows to see redirection:

curl -I -A  UserAgentString  http://www.example.com

curl -I -A  Mozilla/5.0 (iPhone; U; CPU like Mac OS X; en) AppleWebKit/420+ (KHTML, like Gecko) Version/3.0 Mobile/1A543a Safari/419.3  http://www.example.com

curl -I -A  Mozilla/5.0 (iPhone; U; CPU like Mac OS X; en) AppleWebKit/420+ (KHTML, like Gecko) Version/3.0 Mobile/1A543a Safari/419.3   http://www.example.com/?desktop=true

References

Mobile browser detection with Nginx.

Mobile redirection with Nginx.