If I am hosting an Eikon App Studio app, How can I tell if the user is coming from Eikon or from the web?

If I open their URL in Eikon, there will be a cookie named EikonUserAgent:

GET http://www.ikriv.com/ HTTP/1.1
accept: */*
accept-language: en-US,en;q=0.7,ru;q=0.3
accept-encoding: gzip, deflate
user-agent: Mozilla/4.0 (compatible; MSIE 7.0; Windows NT 6.2; WOW64; Trident/7.0; .NET4.0E; .NET4.0C; .NET CLR 3.5.30729; .NET CLR 2.0.50727; .NET CLR 3.0.30729)
host: www.ikriv.com
cookie: EIKON_USER_AGENT="NET45,EIKON9.0.35453,SR0,ADF6.20161.02.11,Charcoal";
__utma=242513818.1037082884.1461678206.1461678206.1461678206.1;
__utmb=242513818; __utmc=242513818;
__utmz=242513818.1461678206.1.1.utmccn=(direct)|utmcsr=(direct)|utmcmd=(none)
Connection: keep-alive

If I open it in a regular browser, there will be no such cookie.

GET http://www.ikriv.com/ HTTP/1.1
Host: www.ikriv.com
Connection: keep-alive
Accept: text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,*/*;q=0.8
Upgrade-Insecure-Requests: 1
User-Agent: Mozilla/5.0 (Windows NT 6.3; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/49.0.2623.112 Safari/537.36
Accept-Encoding: gzip, deflate, sdch
Accept-Language: en-US,en;q=0.8,ru;q=0.6,uk;q=0.4
Cookie: __utma=242513818.645666531.1392999999.1459376629.1459543226.75; __utmz=242513818.1459543226.75.2.utmccn=(referral)|utmcsr=google.com|utmcct=/|utmcmd=referral