错误脚本 额外的环境变量包括CGI 1.1 变量传递给错误脚本。这些CGI 1.1 变量有：
REDIRECT_REQUEST ：这是当正确发送给服务器的请求。
REDIRECT_URL ：这是导致错误的请求URL。
REDIRECT_STATUS ：这是如果NCSA HTTPd 已经允许应答的状态数字和信息。
另外，NCSA HTTPd在err_string=error_message时作为NCSA HTTPd产生的QUERY_STRING错误字符串传递。一些错误信息可以需要一些不在CGI规范中的文件头。基于这个原因，以下给出一个没有解析的文件头的脚本，它是用Perl编写的：
#!/usr/local/bin/perl
# 这是一个利用Perl编写的没有解析文件头的CGI 1.1错误脚本来处理错误请求。
$error = $ENV{'QUERY_STRING'};
$redirect_request = $ENV{'REDIRECT_REQUEST'};
($redirect_method,$request_url,$redirect_protocal) = split(' ',$redirect_request);
$redirect_status = $ENV{'REDIRECT_STATUS'};
if (!defined($redirect_status)) {
$redirect_status = "200 Ok";
}
($redirect_number,$redirect_message) = split(' ',$redirect_status);
$error =~ s/error=//;
$title = "<HEAD><TITLE>".$redirect_status."</TITLE></HEAD>";
if ($redirect_method eq "HEAD") {
$head_only = 1;
} else {
$head_only = 0;
}
printf("%s %s\r\n",$ENV{'SERVER_PROTOCOL'},$redirect_status);
printf("Server: %s\r\n",$ENV{'SERVER_SOFTWARE'});
printf("Content-type: text/html\r\n");
$redirect_status = "<img alt="" src=/images/icon.gif>".$redirect_status;
if ($redirect_number == 302) {
if ($error !~ /http:/) {
printf("xLocation: http://%s:%s%s\r\n",
$ENV{'SERVER_NAME'},
$ENV{'SERVER_PORT'},
$error);
if (!$head_only) {
printf("%s\r\n",$title);
printf("<H1>%s</H1>\r\n",$redirect_status);
printf("This document has moved");
printf("<A HREF="http://%s:%s%s">here</A>.\r\n",
$ENV{'SERVER_NAME'},
$ENV{'SERVER_PORT'},
$error);
}
} else {
printf("Location: %s\r\n",$error);
if (!$head_only) {
printf("%s\r\n",$title);
printf("<H1>%s</H1>\r\n",$redirect_status);
printf("This document has moved");
printf("<A HREF="%s">here</A>.\r\n",$error);
}
}
} elsif ($redirect_number == 400) {
printf("\r\n");
if (!$head_only) {
printf("%s\r\n",$title);
printf("<H1>%s</H1>\r\n",$redirect_status);
printf("Your client sent a request that this server didn't");
printf(" understand.<b>Reason:</b> %s\r\n",$error);
}
} elsif ($redirect_number == 401) {
printf("WWW-Authenticate: %s\r\n",$error);
printf("\r\n");
if (!$head_only) {
printf("%s\r\n",$title);
printf("<H1>%s</H1>\r\n",$redirect_status);
printf("Browser not authentication-capable or ");
printf("authentication failed.\r\n");
}
} elsif ($redirect_number == 403) {
printf("\r\n");
if (!$head_only) {
printf("%s\r\n",$title);
printf("<H1>%s</H1>\r\n",$redirect_status);
printf("Your client does not have permission to get");
printf("URL:%s from this server.\r\n",$ENV{'REDIRECT_URL'});
}
} elsif ($redirect_number == 404) {
printf("\r\n");
if (!$head_only) {
printf("%s\r\n",$title);
printf("<H1>%s</H1>\r\n",$redirect_status);
printf("The requested URL:<code>%s</code> ",
$ENV{'REDIRECT_URL'});
printf("was not found on this server.\r\n");
}
} elsif ($redirect_number == 500) {
printf("\r\n");
if (!$head_only) {
printf("%s\r\n",$title);
printf("<H1>%s</H1>\r\n",$redirect_status);
printf("The server encountered an internal error or ");
printf("misconfiguration and was unable to complete your ");
printf("request "<code>%s</code>"\r\n",$redirect_request);
}
} elsif ($redirect_number == 501) {
printf("\r\n");
if (!$head_only) {
printf("%s\r\n",$title);
printf("<H1>%s</H1>\r\n",$redirect_status);
printf("The server is unable to perform the method ");
printf("<b>%s</b> at this time.",$redirect_method);
}
} else {
printf("\r\n");
if (!$head_only) {
printf("%s\r\n",$title);
printf("<H1>%s</H1>\r\n",$redirect_status);
}
}
if (!$head_only) {
printf("<p>The following might be useful in determining the problem:");
printf("<pre>\r\n");
open(ENV,"env|");
while (<ENV>) {
printf("$_");
}
close(ENV);
printf("</pre>\r\n<hr>");
printf("<A HREF="http://%s:%s/"><img alt="[Back to Top]" src="/images/back.gif"> Back to Root of Server</A>\r\n",
$ENV{'SERVER_NAME'},$ENV{'SERVER_PORT'});
printf("<hr><i><a href="mailto:webmaster\@%s">webmaster\@%s</a></i> / ",
$ENV{'SERVER_NAME'},$ENV{'SERVER_NAME'});
printf("<i><a href="mailto:httpd\@ncsa.uiuc.edu">httpd\@ncsa.uiuc.edu</a></i>");
printf("\r\n");