用perl和lua在nginx中验证url

和三年前的博客一样，还是时间加密钥加路径的加密方式。不过这次改用nginx，这样不用重新缓存后面的squid文件了。
先用ngx_lua做：
```nginx
set $expire “600”;
set $salt “mysalt”;
location ~* .mp3$ {
#local m = ngx.re.match(ngx.var.uri,”^/([0-9]{4})/([0-9]{2})/([0-9]{2})/([0-9]{2})/([0-9]{2})/([0-9a-z]{32})(/.*)”)
#用ngx.re.match就不能%d,用string.match就不能{2}，郁闷
#而且ngx.re.match所有的捕获都在m数组里，这点类似perl的m//返回。
rewrite_by_lua ‘
local date = {}
local md5str
local path
date.year,date.month,date.day,date.hour,date.min,md5str,path = string.match(ngx.var.uri,”^/(%d+)/(%d+)/(%d+)/(%d+)/(%d+)/(%w+)(/%S+)”)

    if date.year == nil then
         ngx.exit(404)
    end
    local time1 = tonumber(os.time(date))
    local time2 = tonumber(ngx.time())
    if md5str == ngx.md5(ngx.var.salt..date.year..date.month..date.day..date.hour..date.min..path) then
        if time2 - time1 < tonumber(ngx.var.expire) then
            ngx.req.set_uri(path)
        else
            ngx.exit(405)
        end
    else
        ngx.exit(403)
    end
    ';  
    proxy_pass         http://backend;
    proxy_set_header   Host     $host;
} ```

然后用nginx_perl做：
```nginx
perl_require POSIX.pm;
perl_require Digest/MD5.pm;
perl_set $realurl ‘
sub {
my $secret = “mysalt”;
my $expire = 600;
my $r = shift;
if ( $r->uri =~ m#^/(\d{4})/(\d{2})/(\d{2})/(\d{2})/(\d{2})/(\w{32})(/\S+.mp3)#oi ) {
my ($year, $mon, $mday, $hour, $min, $md5, $path) = ($1, $2, $3, $4, $5, $6, $7);
my $str = Digest::MD5::md5_hex($secret . $year . $mon . $mday . $hour . $min . $path);
my $reqtime = POSIX::mktime(00, $min, $hour, $mday, $mon - 1, $year - 1900);
my $now = time;
if ( $str eq $md5 and $now - $reqtime < $expire ) {
return $path;
} else {
return “error”;
};
} else {
return “error”;
};
}’;

server {
location ~* .mp3$ {
if ($realurl = “error”) { return 403; }
proxy_pass http://music_store_local$realurl;
proxy_set_header Host $host;
}
}
```

然后用http_load测试单url响应情况，基本效率一样。在压力比较大(lo上跑大概200MB/s，再大就可能出错了)的情况下，第一字节响应时间大概比直接请求squid多一个数量级（从0.4ms到4ms）
这个情况下，squid的cpu%在130％，nginx_perl的worker是25％，nginx_lua的是19％。