YggDore Sky Gate specification
5. Redirect to service
A login user sends (1) of step2 to YggDore Sky Gate Server.

Next, The YSG Server readies authorization and returning user ID.

In this case, @YSI@ keyword of (1) converts to interface url to get the user ID.
http://www.service.com/login/?%40ysg=%40YSI%40 --- (1)
http://www.service.com/login/?ysg=https://www.yskygate.com/auth/
Login information format is added because YSG Server receives login user information from service owner.
http://www.hogehoge.com/login/?ysg=https://www.yskygate.com/auth/?@cip=@YCIP@&@ca=@YCUA@&wn=@YWN@
Service owner must converts the following keywords and accesses to the url.

@YCIP@ => Login user’s IP address
@YCUA@ => Login user’s user agent (Browser information)
@YWN@ => World(Not required)

The world is set of service. If you have bbs service (bbs.hogehoge.com) and chat service (chat.hogehoge.com), YggDore Sky Gate returned different user id per service normally.
But YggDore Sky Gate has sharing user id function.

In this case, you allow to share com level(.com) or hogehoge.com level. You are able to set stand alone service (bbs.hogehoge.com or char.hogehoge.com) too. Other domains is not able to set.
http://www.service.com/login/?ysg=https://www.yskygate.com/auth/?@cip=@YCIP@&@ca=@YCUA@&wn=@YWN@&rnd=12345678901234567890
The url is added random string because security upgrades.

The last, the ysg data encodes to url format.
The login user accesses to its site.
The web request data is POST format.
http://www.service.com/login/?ysg=http%3a%2f%2fwww%2eyskygate%2ecom%2fauth%2f%3f%0d%0a%40cip%3d%40YCIP%40%26%40ca%3d%40YCUA%40%26wn%3d%40YWN%40%26rnd%3d12345678901234567890 --- (3)
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