iteration

lib/lns.lua

@@ -0,0 +1,79 @@
+local cache = {}
+
+settings.define("lns_client.allow_dynamic_lns_hosts", {
+    description = "Allow dynamic LNS hosts",
+    type = "boolean",
+    default = false
+})
+
+settings.define("lns_client.lns_server", {
+    description = "LNS Server Rednet ID",
+    type = "number",
+    default = 8
+})
+
+
+function _load_cache()
+    if fs.exists("lns_cache.db") then
+        db = fs.open("lns_cache.db", "r")
+        db_contents = db.readAll()
+        db.close()
+
+        cache = textutils.unserialize(db_contents)
+    end
+end
+
+function _save_cache()
+    db = fs.open("lns_cache.db", "w")
+    db.write(textutils.serialize(cache))
+    db.close()
+end
+
+function server()
+    local lns_server_id = settings.get("lns_client.lns_server")
+    local allow_dynamic_lns_hosts = settings.get("lns_client.allow_dynamic_lns_hosts")
+
+    if allow_dynamic_lns_hosts then
+        lns_server_id = rednet.lookup("lns", lns_server)
+        if lns_server_id == nil then
+            io.write("LNS Server not found!\n")
+            return nil
+        end
+    end
+
+    return lns_server_id
+end
+
+function lookup(remote_hostname)
+
+    _load_cache()
+    if cache[remote_hostname] ~= nil then
+        return cache[remote_hostname]
+    end
+
+    local data = {
+        ["action"] = "lookup",
+        ["hostname"] = remote_hostname
+    }
+
+    rednet.send(server(), data, "lns")
+
+    while true do
+        id, msg = rednet.receive("lns")
+        if id == lns_server_id then
+            if msg == nil then
+                return nil
+            else
+                cache[remote_hostname] = msg
+                _save_cache()
+                return msg
+            end
+        end
+    end
+end
+
+function clear_cache()
+    cache = {}
+    _save_cache()
+    print("Cleared cache!")
+end