Introduce cache to immediately update UI when socket client connects (#176)

util/cache.go

@@ -0,0 +1,58 @@
+package util
+
+import "sync"
+
+// Cache is a data store
+type Cache struct {
+	sync.Mutex
+	val map[string]interface{}
+}
+
+// NewCache creates cache
+func NewCache() *Cache {
+	return &Cache{val: make(map[string]interface{})}
+}
+
+// Run adds input channel's values to cache
+func (c *Cache) Run(in <-chan Param) {
+	for p := range in {
+		c.Add(p.Key, p)
+	}
+}
+
+// All provides a copy of the cached values
+func (c *Cache) All() []Param {
+	c.Lock()
+	defer c.Unlock()
+
+	copy := make([]Param, 0, len(c.val))
+	for _, v := range c.val {
+		if param, ok := v.(Param); ok {
+			copy = append(copy, param)
+		}
+	}
+
+	return copy
+}
+
+// Add entry to cache
+func (c *Cache) Add(key string, param Param) {
+	c.Lock()
+	defer c.Unlock()
+
+	c.val[key] = param
+}
+
+// Get entry from cache
+func (c *Cache) Get(key string) Param {
+	c.Lock()
+	defer c.Unlock()
+
+	if val, ok := c.val[key]; ok {
+		if param, ok := val.(Param); ok {
+			return param
+		}
+	}
+
+	return Param{}
+}