adding Content-Length header in header_filter_by_lua ?

[Pahud Hsieh]

Hello,

Is it possible to generate the Content-Length header in header_filter_by_lua ?

How to get the exact size of the response body like the following example?

thanks,

location = /now {
        chunked_transfer_encoding off;
        content_by_lua_block {
                local buf = ngx.now()
                --ngx.header["Content-Length"] = #tostring(buf)
                ngx.print( buf )
        }
        header_filter_by_lua_block {
                ngx.header["Content-Length"] = nil
        }
}