go get github.com/cnjack/go-qrcode
cd %GOPATH%/src/github.com/cnjack/go-qrcode(win) cd $GOPATH/src/github.com/cnjack/go-qrcode(mac or linux)
cd install
go build main.go
run main.exe or ./main
visit http://localhost:8080/(you can change the port at qrcode Line 18)
API
visit http://localhost:port/api?qr_string=[qr_string]&size=[size]
to get the image of the qrcode