changes to ngx.arg[1] not getting reflected in final response

[jdewald]

vamshi Wrote:
-------------------------------------------------------
> header_filter_by_lua '
>                 ngx.header.content_length = nil
>                 ngx.header.set_cookie = nil
> 
>                 if ngx.header.location then
>                     local _location = ngx.header.location
>                     _location = ngx.escape_uri(_location)
>                     _location = "http://10.0.9.44/?_redir_=" ..
> _location
>                     ngx.header.location = _location
>                 end
>             ';
> 
>             body_filter_by_lua '
> 
>                 local escUri = function (m)
>                     local _esc = "href=\\"http://10.0.9.44/?_redir_="
> .. ngx.escape_uri(m[1]) .. "\\""
>                     print(_esc)
>                     return _esc
>                 end
> 
>                 local chunk, eof = ngx.arg[1], ngx.arg[2]
>                 local buffered = ngx.ctx.buffered
>                 if not buffered then
>                     buffered = {}
>                     ngx.ctx.buffered = buffered
>                 end
> 
>                 if chunk ~= "" then
>                     buffered[#buffered + 1] = chunk
>                     ngx.arg[1] = nil
>                 end
> 
>                 if eof then
>                     local whole = table.concat(buffered)
>                     ngx.ctx.buffered = nil
>                     local newStr, n, err = ngx.re.gsub(whole,
> "href=\\"(.*)\\"", escUri, "i")
>                     ngx.arg[1] = whole
>                     print(whole)
>                 end
>             ';
> ... 
> 
> 
> As you can see, print(_esc) show that the URL was successfully
> URLencoded. Yet, the print(whole) line does not reflect the gsub()
> 
> What could be issue here ?
> 
> -Vamshi

gsub is going to return the results of the substitution, not do it inline.
You should be outputting/assigning newStr not whole. 

Cheers,
Josh

Posted at Nginx Forum: http://forum.nginx.org/read.php?2,251248,251425#msg-251425