on_message_publish username is a table, not string

[saeid-ir]

Hi,
As what the docs say username for on_message_publish function should be string, but when I debug it using print and some helper functions I realize that its a table without any data in it.
This is a function I used to print username and it gives me an empty table.

function print_table(node)
    local cache, stack, output = {},{},{}
    local depth = 1
    local output_str = "{\n"

    while true do
        local size = 0
        for k,v in pairs(node) do
            size = size + 1
        end

        local cur_index = 1
        for k,v in pairs(node) do
            if (cache[node] == nil) or (cur_index >= cache[node]) then

                if (string.find(output_str,"}",output_str:len())) then
                    output_str = output_str .. ",\n"
                elseif not (string.find(output_str,"\n",output_str:len())) then
                    output_str = output_str .. "\n"
                end

                -- This is necessary for working with HUGE tables otherwise we run out of memory using concat on huge strings
                table.insert(output,output_str)
                output_str = ""

                local key
                if (type(k) == "number" or type(k) == "boolean") then
                    key = "["..tostring(k).."]"
                else
                    key = "['"..tostring(k).."']"
                end

                if (type(v) == "number" or type(v) == "boolean") then
                    output_str = output_str .. string.rep('\t',depth) .. key .. " = "..tostring(v)
                elseif (type(v) == "table") then
                    output_str = output_str .. string.rep('\t',depth) .. key .. " = {\n"
                    table.insert(stack,node)
                    table.insert(stack,v)
                    cache[node] = cur_index+1
                    break
                else
                    output_str = output_str .. string.rep('\t',depth) .. key .. " = '"..tostring(v).."'"
                end

                if (cur_index == size) then
                    output_str = output_str .. "\n" .. string.rep('\t',depth-1) .. "}"
                else
                    output_str = output_str .. ","
                end
            else
                -- close the table
                if (cur_index == size) then
                    output_str = output_str .. "\n" .. string.rep('\t',depth-1) .. "}"
                end
            end

            cur_index = cur_index + 1
        end

        if (size == 0) then
            output_str = output_str .. "\n" .. string.rep('\t',depth-1) .. "}"
        end

        if (#stack > 0) then
            node = stack[#stack]
            stack[#stack] = nil
            depth = cache[node] == nil and depth + 1 or depth - 1
        else
            break
        end
    end

    -- This is necessary for working with HUGE tables otherwise we run out of memory using concat on huge strings
    table.insert(output,output_str)
    output_str = table.concat(output)

    print(output_str)
end

And this is my on_message_publish :

function on_message_publish(clientid, username, topic, payload, qos, retain)
    print_table(username)
    -- do your job here
    return topic, payload, qos, retain
end

I also facing same issue in string handling. I need to remove some character from my string then return to the topic but it seems that gmatch function or for loop statement do not work on lua_hook plugins.

function on_message_publish(clientid, username, topic, payload, qos, retain)
  dataStr = payload:match("(%[.-%])")
  string = ''
  for data in dataStr:gmatch("%b{}") do
   string = string .. data:match(':"(.-)",') .. ';' .. data:match('e":(.-)}') .. ','
  end
    return topic, string, qos, retain
  end

[saeid-ir]

I also find that this problem is related to all plugins even plugins written in Erlang
emqx/emqx#3652