--
-- MySQL LUA Script
-- To log SQL errors to the server log.
-- lib_mysqludf_log() is required
--
local flag = false
function read_query( packet )
    if packet:byte() == proxy.COM_QUERY then
        local user = proxy.connection.client.username
        local host = proxy.connection.client.src.name
        proxy.queries:append(1, packet, {resultset_is_needed = true})
        proxy.queries:append(2, string.char(proxy.COM_QUERY) .. "SET @badquery = \"" .. string.sub(packet, 2) .. "\"", {resultset_is_needed = true} )
        proxy.queries:append(3, string.char(proxy.COM_QUERY) .. "SET @baduser = \"" .. user .. "\"", {resultset_is_needed = true} )
        proxy.queries:append(4, string.char(proxy.COM_QUERY) .. "SET @badhost = \"" .. host .. "\"", {resultset_is_needed = true} )
        proxy.queries:append(5, string.char(proxy.COM_QUERY) .. "SHOW WARNINGS", {resultset_is_needed = true} )
        return proxy.PROXY_SEND_QUERY
    end
end


function write_log(error_type, error_code, error_message)
    local query = "SELECT LOG_ERROR(CONCAT(\"SQL-Error: \",NOW(),\" \",@baduser,\"@\",@badhost,\" -> \",\"" .. error_type .. "\",\"" .. " " .. "\",\"" .. error_code .. "\",\"" .. ": " .. "\",\"" .. error_message .. " -- \",@badquery))"  
    proxy.queries:append(6, string.char(proxy.COM_QUERY) .. query, {resultset_is_needed = true})
    return proxy.PROXY_SEND_QUERY
end


function read_query_result(inj)
    local res = assert(inj.resultset)
    if inj.id == 1 then
        flag = false
        if res.query_status == proxy.MYSQLD_PACKET_ERR then
            flag = true
            return proxy.PROXY_IGNORE_RESULT
        end
    elseif inj.id == 2 or inj.id == 3 or inj.id == 4 or inj.id == 6 then
        return proxy.PROXY_IGNORE_RESULT
    elseif inj.id == 5 then
        if flag == true then
            for row in res.rows do
                proxy.response.type = proxy.MYSQLD_PACKET_ERR
                proxy.response.errmsg = row[3]
                write_log(row[1], row[2], row[3])
            end
            return proxy.PROXY_SEND_RESULT
        end
        return proxy.PROXY_IGNORE_RESULT
    end
end