Fossil

  if( etag_tag()[0]!=0
   && iReplyStatus==200
   && strcmp(zContentType,"text/html")!=0
  ){
    /* Do not cache HTML replies as those will have been generated and
    ** will likely, therefore, contains a nonce and we want that nonce to
    ** be different every time. */
    blob_appendf(&hdr, "ETag: \"%s\"\r\n", etag_tag());
    blob_appendf(&hdr, "Cache-Control: max-age=%d\r\n", etag_maxage());
    if( etag_mtime()>0 ){
      blob_appendf(&hdr, "Last-Modified: %s\r\n",
              cgi_rfc822_datestamp(etag_mtime()));
    }
  }else if( g.isConst ){
    /* isConst means that the reply is guaranteed to be invariant, even

  if( zToken==0 ){
    malformed_request("malformed HTTP header");
  }
  if( fossil_strcmp(zToken,"GET")!=0
   && fossil_strcmp(zToken,"POST")!=0
   && fossil_strcmp(zToken,"HEAD")!=0
  ){
    malformed_request("unsupported HTTP method: \"%s\" - Fossil only supports "
                      "GET, POST, and HEAD", zToken);
  }
  cgi_setenv("GATEWAY_INTERFACE","CGI/1.0");
  cgi_setenv("REQUEST_METHOD",zToken);
  zToken = extract_token(z, &z);
  if( zToken==0 ){
    malformed_request("malformed URI in the HTTP header");