added sessions and flash storage

flash.go

@@ -0,0 +1,57 @@
+package tuu
+
+import "encoding/json"
+
+// flashKey is the prefix inside the Session.
+const flashKey = "_flash_"
+
+//Flash is a struct that helps with the operations over flash messages.
+type Flash struct {
+	data map[string][]string
+}
+
+//Delete removes a particular key from the Flash.
+func (f Flash) Delete(key string) {
+	delete(f.data, key)
+}
+
+//Clear removes all keys from the Flash.
+func (f *Flash) Clear() {
+	f.data = map[string][]string{}
+}
+
+//Set allows to set a list of values into a particular key.
+func (f Flash) Set(key string, values []string) {
+	f.data[key] = values
+}
+
+//Add adds a flash value for a flash key, if the key already has values the list for that value grows.
+func (f Flash) Add(key, value string) {
+	if len(f.data[key]) == 0 {
+		f.data[key] = []string{value}
+		return
+	}
+
+	f.data[key] = append(f.data[key], value)
+}
+
+//Persist the flash inside the session.
+func (f Flash) persist(session *Session) {
+	b, _ := json.Marshal(f.data)
+	session.Set(flashKey, b)
+	session.Save()
+}
+
+//newFlash creates a new Flash and loads the session data inside its data.
+func newFlash(session *Session) *Flash {
+	result := &Flash{
+		data: map[string][]string{},
+	}
+
+	if session.Session != nil {
+		if f := session.Get(flashKey); f != nil {
+			json.Unmarshal(f.([]byte), &result.data)
+		}
+	}
+	return result
+}