Re: [openresty-en] Re: gzip decoding

agentzh

Hello!

On Tue, Mar 26, 2013 at 4:02 PM,  <jdavidmitchell@gmail.com> wrote:
> On Friday, March 1, 2013 3:15:40 PM UTC-5, Ron Gomes wrote:
>>
>> Our URL rewriter has to interpret a request cookie whose value is a JSON
>> object that's been gzipped, encrypted, and base64-encoded. All the pieces I
>> need for this are part of the openresty bundle except for gzip decoding (as
>> far as I can tell).
>>
>> There seem to be several packages for this available in the wild.  Can
>> someone suggest the best and easiest way that I can add gzip decoding
>> capability to our server?
>
> I have the same issue.  Our cookie is gzipped (libz) and URL encoded.  We
> are using PHP.  PHP automatically url decodes a cookie, and we run
> gzuncompress.  I would be great if we could replace our PHP with lua.
>

IMHO, the simplest solution is just to use LuaJIT's FFI API to call
zlib's C API directly from within a custom Lua module. The official
FFI tutorial does contain a sample for accessing zlib:

    http://luajit.org/ext_ffi_tutorial.html

Best regards,
-agentzh

justin

On Tue, Mar 26, 2013 at 11:06 PM, agentzh <age...@gmail.com> wrote:

IMHO, the simplest solution is just to use LuaJIT's FFI API to call
zlib's C API directly from within a custom Lua module. The official
FFI tutorial does contain a sample for accessing zlib:

http://luajit.org/ext_ffi_tutorial.html

Best regards,
-agentzh

As nginx is already linked to zlib, would it make sense to include a standard ffi binding with openresty (also potentially applies to openssl, which has lots of useful functions, and maybe pcre)?

Justin

agentzh

Hello!

On Sat, Mar 30, 2013 at 6:35 AM, Justin Cormack wrote:
> As nginx is already linked to zlib, would it make sense to include a standard ffi binding with openresty (also potentially applies to openssl, which has lots of useful functions, and maybe pcre)?
>

The lua-resty-string library bundled by ngx_openresty already provides
the FFI binding for some C API in both the Nginx core and OpenSSL:

https://github.com/agentzh/lua-resty-string

We may expect lua-resty-zlib and more :)

The PCRE FFI binding is tricky because the Nginx core hijacked the
PCRE allocator, hence the existing ngx.re API provided by ngx_lua.
There will be an FFI implementation for the ngx.re API in ngx_lua's
"ffi" git branch when the LuaJIT's JIT compiler itself is more feature
complete (like implementing the CAT bytecode and the table.concat
builtin). For now, most real-world FFI-based Lua code still cannot be
JIT compiled anyway because most of web apps use string operations
extensively, which cannot be compiled by the current LuaJIT's JIT
compiler after all (Mike Pall says he will address this in LuaJIT 2.1
and beyond).

Best regards,
-agentzh