How nginx's "location if" works (Was Re: Setting cache parameter via if directives)

[Alexander Kunz]

Good Morning Agentzh,

thanks so much, again :) I will play around with ndk.set_var. I think 
now i have all parts together for building
a whole webapp only with nginx + lua and a datastorage :) cool.

If it runs, i will give you a feedback.

Have a nice weekend.

Alexander


On 19.02.2011 07:06, agentzh wrote:
> On Fri, Feb 18, 2011 at 8:29 PM, Alexander Kunz<akunz at ntmedia.de>  wrote:
>> Time to think a bit different :) The "old" way still stuck in my head. I see
>> there is a function access_by_lua but i still like session. Could this the
>> way to handle access to all files in app?
> Sure :)
>
>> Decrypt session and encrypt
>> session for refreshing the session livetime?
> Yeah :)
>
>> Or shoud i use access_by_lua in
>> each location?
>>
> Well, this is a valid option too: you can combine
> ngx_encrypted_session and access_by_lua by calling
> ngx_ecrypted_session's config directives directly from within Lua,
> like this:
>
>     access_by_lua '
>         local encrypted_text = ndk.set_var.set_decode_base32(ngx.var.arg_session)
>         if not encrypted_text or encypted_text == "" then
>             return ngx.redirect("/relogin.htm?url=" ..
> ngx.escape_uri(ngx.var.uri))
>         end
>
>         local raw_text = ndk.set_var.set_decrypt_session(encrypted_text)
>         if not raw_text or raw_text == "" then
>             return ngx.redirect("/relogin.htm?url=" ..
> ngx.escape_uri(ngx.var.uri))
>         end
>
>         -- validate raw_text is indeed valid...
>
>         -- then refresh the sessions:
>         local encrypted_text = ndk.set_var.set_encrypt_session(raw_text)
>         local value = ndk.set_var.set_encode_base32(encrypted_text)
>         ngx.header["Set-Cookie"] = { "SID=" .. value .. "; path=/" }
>     ';
>
> A very useful feature in ngx_lua is the "ndk.set_var.xxx" magic that
> allows you to call some other nginx C modules' config directives
> on-the-fly! There's a restriction though: the 3rd-party directives
> must be implemented using NDK (Nginx Devel Kit)'s set_var submodule's
> ndk_set_var_value mechanism ;)
>
>> Have a nice day, agentzh.
>>
> You too! ;)
>
> Cheers,
> -agentzh