Thanks for the answer Robin, it helped a lot.

The answer to this one is complicated.  
If you are trying to send data that is sent to the printer to a web host, as in passing data through the printer:
It uses multiple SGD commands to set this up.  First you need to set up the data capture system using the "capture" SGD commands.  Set the delimiter and the port you want to read the commands from.  Then you set a zebranet alert for "SGD SET" and set the destination to "HTTP-POST", preferably using the "alerts" SGD rather than the ZPL command. https://www.zebra.com/content/dam/zebra/manuals/printers/common/program… can all be configured in the ZBI program.  You then use ZBI to send data to the port for capture or let the user back-end send data to that port and the printer will send that up to the server as a POST alert. 
If you are trying to send data from a webservice to the printer to be used by ZBI, That is a little harder, ZBI is only set up to accept data over specific ports and HTTP/S is not one of them.  It is better to do the data manipulation on the server and send the printer the ZPL or print data ready to print without ZBI.  You can use the Savanna Printers-Print API to do this.  
Robin West
Zebra Developer Advocate