WeOCR servers can be used non-interactively as well as via an HTML page. To do so, you just call the CGI program directly using a web tool such as cURL.
Example:
$ curl -F userfile=@Image_File_Name \
-F outputencoding="utf-8" \
-F outputformat="txt" \
http://Server_Address/cgi-bin/weocr/submit_e1.cgi >result.txt
You probably need to use --max-time and --connect-timeout options as well to avoid undesirable blockings of the process.
If you specify outputformat="txt", the first line of the output data is used as the status line. The first line will be blank upon successful recognition.
See WeOCR Server API document for details.