Move the provider switch into the provider package

app.go

@@ -25,6 +25,11 @@ type DBConfig struct {
 	Args    string `json:"args"`
 }
 
+type ProviderConfig struct {
+	Provider string          `json:"provider"`
+	Config   json.RawMessage `json:"conf"`
+}
+
 type ML struct {
 	Id          string            `json:"id"`
 	Title       map[string]string `json:"title"`
@@ -32,9 +37,8 @@ type ML struct {
 }
 
 type MLConfig struct {
-	Provider string          `json:"provider"`
-	Config   json.RawMessage `json:"conf"`
-	Lists    []ML            `json:"lists"`
+	ProviderConfig
+	Lists []ML `json:"lists"`
 }
 
 type AppConfig struct {
@@ -95,26 +99,10 @@ func CreateApp(cfg AppConfig) (app *App) {
 		ctx.Data["db"] = db
 		ctx.Data["app"] = app
 	})
-	m.Use(func(ctx *macaron.Context) {
-		var ml mailinglistprovider.MailinglistProvider
-
-		if app.cfg.Mailinglists.Provider == "mailman2" {
-			var cfg mailinglistprovider.Mailman2ProviderConfig
-			err := json.Unmarshal(app.cfg.Mailinglists.Config, &cfg)
-			if err != nil {
-				panic(err)
-			}
-
-			ml, err = mailinglistprovider.CreateMailman2Provider(cfg)
-			if err != nil {
-				panic(err)
-			}
-		}
-
-		ctx.MapTo(ml, (*mailinglistprovider.MailinglistProvider)(nil))
-	})
+	m.Use(mailinglistprovider.Mount(app.cfg.Mailinglists.Provider, app.cfg.Mailinglists.Config))
 
 	auth := remoteauthprovider.CreateOAuth2AuthProvider(m, db, app.cfg.OAuth2)
+
 	m.Group("/user", func() {
 		m.Combo("/login").
 			Get(auth.GetLogin).

mailinglistprovider/mailinglistprovider.go

 package mailinglistprovider
 
+import (
+	"encoding/json"
+	"gopkg.in/macaron.v1"
+)
+
 type MailinglistProvider interface {
 	IsSubscribed(email string) bool
 	Subscribe(email string)
 	Unsubscribe(email string)
 }
+
+// Use this function using app.Use() on your macaron app to mount auth providers
+func Mount(provider string, config json.RawMessage) func(*macaron.Context) {
+	return func(ctx *macaron.Context) {
+		var ml MailinglistProvider
+
+		switch provider {
+		case "mailman2":
+			var cfg Mailman2ProviderConfig
+			err := json.Unmarshal(config, &cfg)
+			if err != nil {
+				panic(err)
+			}
+
+			ml, err = CreateMailman2Provider(cfg)
+			if err != nil {
+				panic(err)
+			}
+
+			break
+
+		default:
+			panic("unknown mailinglist provider")
+		}
+
+		ctx.MapTo(ml, (*MailinglistProvider)(nil))
+	}
+}