Faild to SET empty string to KEY via PUT method

[vimagick]

Webdis returns error when PUT empty string.

$ curl http://127.0.0.1:7379/SET/hello/
{"SET":[true,"OK"]}

$ touch empty.txt

$ stat -c %s empty.txt
0

$ curl -T empty.txt http://127.0.0.1:7379/SET/hello
{"SET":[false,"ERR wrong number of arguments for 'set' command"]}