add google login

internal/auth/service.go

@@ -0,0 +1,48 @@
+package auth
+
+import (
+	"sort"
+
+	"github.com/gorilla/sessions"
+	"github.com/markbates/goth"
+	"github.com/markbates/goth/gothic"
+	"github.com/markbates/goth/providers/google"
+)
+
+type Service struct {
+	secret            string
+	googleClientId    string
+	googleSecret      string
+	googleRedirectUrl string
+}
+
+type ProviderIndex struct {
+	ProvidersMap map[string]string
+	Providers    []string
+}
+
+func NewService(secret, googleClientId, googleSecret, googleRedirectUrl string) *Service {
+	return &Service{
+		secret,
+		googleClientId,
+		googleSecret,
+		googleRedirectUrl,
+	}
+}
+
+func (as Service) GetProviderIndex() *ProviderIndex {
+	goth.UseProviders(google.New(as.googleClientId, as.googleSecret, as.googleRedirectUrl))
+
+	m := map[string]string{
+		"google": "Google",
+	}
+	var keys []string
+	for k := range m {
+		keys = append(keys, k)
+	}
+	sort.Strings(keys)
+
+	gothic.Store = sessions.NewCookieStore([]byte(as.secret))
+
+	return &ProviderIndex{Providers: keys, ProvidersMap: m}
+}