map configuration

foxgab nginx-forum at
Wed Jul 5 05:59:52 UTC 2017

that means, if the value of $http_upgrade is null or that variable doesn't
exist, the value of $connection_upgrade will set to "close", or it will set
to "upgrade" in the other cases.

the $http_upgrade is the value of the "Upgrade" header in the client

Posted at Nginx Forum:,275283,275304#msg-275304

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