Use filesystem based kv store instead of sqlite

model/app.go

@@ -1,19 +1,40 @@
 package model
 
-import "errors"
+import (
+	"errors"
+	"strings"
+)
 
 var (
 	ErrAppNotFound = errors.New("app not found")
 )
 
 type App struct {
-	InstanceURL  string
-	ClientID     string
-	ClientSecret string
+	InstanceDomain string
+	InstanceURL    string
+	ClientID       string
+	ClientSecret   string
 }
 
 type AppRepository interface {
 	Add(app App) (err error)
-	Update(instanceURL string, clientID string, clientSecret string) (err error)
-	Get(instanceURL string) (app App, err error)
+	Get(instanceDomain string) (app App, err error)
+}
+
+func (a *App) Marshal() []byte {
+	str := a.InstanceURL + "\n" + a.ClientID + "\n" + a.ClientSecret
+	return []byte(str)
+}
+
+func (a *App) Unmarshal(instanceDomain string, data []byte) error {
+	str := string(data)
+	lines := strings.Split(str, "\n")
+	if len(lines) != 3 {
+		return errors.New("invalid data")
+	}
+	a.InstanceDomain = instanceDomain
+	a.InstanceURL = lines[0]
+	a.ClientID = lines[1]
+	a.ClientSecret = lines[2]
+	return nil
 }