ServerVar

Get value of Server variable by passing variable name
aVar can be any of these value:
ALL_HTTP, ALL_RAW, APPL_MD_PATH, APPL_PHYSICAL_PATH, AUTH_PASSWORD, AUTH_TYPE, AUTH_USER, CERT_COOKIE, CERT_FLAGS, CERT_ISSUER, CERT_KEYSIZE, CERT_SECRETKEYSIZE, CERT_SERIALNUMBER, CERT_SERVER_ISSUER, CERT_SERVER_SUBJECT, CERT_SUBJECT, CONTENT_LENGTH, CONTENT_TYPE, GATEWAY_INTERFACE, HTTPS, HTTPS_KEYSIZE, HTTPS_SECRETKEYSIZE, HTTPS_SERVER_ISSUER, HTTPS_SERVER_SUBJECT, INSTANCE_ID, INSTANCE_META_PATH, LOCAL_ADDR, LOGON_USER, PATH_INFO, PATH_TRANSLATED, QUERY_STRING, REMOTE_ADDR, REMOTE_HOST, REMOTE_USER, REQUEST_METHOD, SCRIPT_NAME, SERVER_NAME, SERVER_PORT, SERVER_PORT_SECURE, SERVER_PROTOCOL, SERVER_SOFTWARE, URL, HTTP_CONNECTION, HTTP_ACCEPT, HTTP_ACCEPT_ENCODING, HTTP_ACCEPT_LANGUAGE, HTTP_COOKIE, HTTP_HOST, HTTP_USER_AGENT, HTTP_UPGRADE_INSECURE_REQUESTS