how to return ipv4 address only.... about lua-resty-dns

[herono2010]

local answers, err, tries = r:query(host_name, { qtype = r.TYPE_A })
the answers also have some cname (type:5) value....

[Viste]

                local ans, err = r:tcp_query(host, { qtype = TYPE_A })
                if not ans then
                    ngx.log(ngx.ERR, "got an error on query: ", err)
                    return ngx.exit(ngx.HTTP_GATEWAY_TIMEOUT)
                end

                for k,answer in pairs(ans) do
                    return answer.address
                end

[rulatir]

                local ans, err = r:tcp_query(host, { qtype = TYPE_A })
                if not ans then
                    ngx.log(ngx.ERR, "got an error on query: ", err)
                    return ngx.exit(ngx.HTTP_GATEWAY_TIMEOUT)
                end

                for k,answer in pairs(ans) do
                    return answer.address
                end

Three questions:

1. Should it be TYPE_A or r.TYPE_A? Which one is correct?
2. Is changing r.TYPE_A to TYPE_A exactly the change that turns this piece of code from non-working to working?
3. If 2. is true, does it mean that TYPE_A is a global constant and r.TYPE_A is nil, which is why { qtype = r.TYPE_A } is effectively {}?

[Viste]

@rulatir No, when I wrote it I made a mistake, there must be r.TYPE_A
this is 100% working code with checks for return ipv4 or ipv6 depends on which version the connection was made from

                local r, err = resolver:new{
                    nameservers = something
                    retrans = 5,
                    timeout = 5000,
                    no_recurse = true 
                }
    
                if not r then
                    ngx.log(ngx.ERR, "resolver communicate error: ", err)
                    return
                end

                local qtype

                if checkIfIpv4(ngx.var.remote_addr) then -- check from what version of IPv we get the request
                    qtype = r.TYPE_A
                else
                    qtype = r.TYPE_AAAA
                end

                local ans, err = r:tcp_query(host, { qtype = qtype })
                if not ans then
                    ngx.log(ngx.ERR, "got an error on query: ", err)
                    return ngx.exit(ngx.HTTP_BAD_GATEWAY) --or something else
                end

                    if ans.errcode ~= nil then -- check if we get errcode in ans query
                        return ngx.exit(ngx.HTTP_BAD_GATEWAY) --or something else
                    else
                        if not next(ans) then -- check for empty ans
                            ngx.exit(ngx.HTTP_BAD_GATEWAY) --or something else
                        end
                        for k,answer in pairs(ans) do -- itr ans-query for get raw IP from ans
                            if  not answer.address then
                                return ngx.exit(ngx.HTTP_BAD_GATEWAY) -- --or something else
                            else
                                 return answer.address
                            end            
                        end
                    end

checkIfIpv4 func code

                local function checkIfIpv4(ip)
                    if ip == nil or type(ip) ~= "string" then
                        return false
                    end

                    -- check for format 1.11.111.111 for ipv4
                    local chunks = {ip:match("(%d+)%.(%d+)%.(%d+)%.(%d+)")}

                    if (#chunks == 4) then
                        for _,v in pairs(chunks) do
                            if (tonumber(v) < 0 or tonumber(v) > 255) then
                                return false
                            end
                        end
                        return true
                    else
                        return false
                    end
                end

[rulatir]

Thanks!

[Viste]

@rulatir you're welcome :)