Update 'DynDNS/dyndns.lua'

Improved DNS records change checks

DynDNS/dyndns.lua

@@ -74,6 +74,48 @@ function read_file(path)
     return content
 end
 
+function pairs_by_keys(t, f)
+    local a = {}
+    for n in pairs(t) do
+        table.insert(a, n)
+    end
+    table.sort(a, f)
+    local i = 0      -- iterator variable
+    local iter = function ()   -- iterator function
+        i = i + 1
+        if a[i] == nil then
+            return nil
+        else
+            return a[i], t[a[i]]
+        end
+    end
+    return iter
+end
+
+function sort_table(my_table)
+    local t = {}
+    for title,value in pairs_by_keys(my_table) do
+        table.insert(t, { title = title, value = value })
+    end
+    my_table = t
+    return my_table
+end
+
+function compare_tables(a,b)
+    if #a ~= #b then return false end
+    local t1,t2 = {}, {}
+    for k,v in pairs(a) do
+        t1[k] = (t1[k] or 0) + 1
+    end
+    for k,v in pairs(b) do
+        t2[k] = (t2[k] or 0) + 1
+    end
+    for k,v in pairs(t1) do
+        if v ~= t2[k] then return false end
+    end
+    return true
+end
+
 
 array = {}
 
@@ -135,9 +177,14 @@ for key,value in pairs(array) do
 	end
 end
 
-if read_file(output_file) ~= config then
+config_file = read_file(output_file)
+
+c1 = sort_table(split(config_file, "\r\n"))
+c2 = sort_table(split(config, "\r\n"))
+
+if not compare_tables(c1, c2) then
 	file = io.open(output_file, "w")
 	file:write(config)
 	file:close()
 	os.execute(reload_command)
-end
+end