An example of how nginx implements if nesting

Nginx does not support if nesting, nor does it allow logical judgment in if. The following error will be reported:

Nginx: [emerg] "if" directive is not allowed

When the business needs multiple conditional judgments, it can be realized with the help of intermediate variables.

For example, our website has multiple sub-domain names on the pc side, while there is only one domain name on the mobile end. The corresponding relationship is as follows:

Www.test.com-- > m.test.comsub1.test.com-- > m.test.com/sub1sub2.test.com-- > m.test.com/sub2sub3.test.com-- > m.test.com/sub3

Effect to be achieved: 301 jumps to the corresponding mobile domain name when the pc domain name is accessed on the mobile side

The rewriting rules for nginx are as follows:

# whether it is the mobile set $mobile 0 if ($http_user_agent ~ * (mobile | nokia | iphone | ipad | android | samsung | htc | blackberry) {set $mobile 1;} # acquire the subdomain set $prefix 1 if ($host ~ * "sub1.test.com") {set $prefix 2;} if ($host ~ * "sub2.test.com") {set $prefix 3;} if ($host ~ * "sub3.test.com") {set $prefix 4;} set $sign "$mobile} ${prefix}" If ($sign = 11) {rewrite ^ (. *) http://m.test.com$1 permanent;} if ($sign = 12) {rewrite ^ (. *) http://m.test.com/sub1$1 permanent;} if ($sign = 13) {rewrite ^ (. *) http://m.test.com/sub2$1 permanent;} if ($sign = 14) {rewrite ^ (. *) http://m.test.com/sub3$1 permanent;}

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