Add single instance mode

2 files changed, 61 insertions, 32 deletions

diff --git a/service/service.go b/service/service.go
index be83bd0..02c55cb 100644
--- a/service/service.go
+++ b/service/service.go
@@ -35,6 +35,7 @@ type Service interface {
 	ServeSearchPage(ctx context.Context, c *model.Client, q string, qType string, offset int) (err error)
 	ServeUserSearchPage(ctx context.Context, c *model.Client, id string, q string, offset int) (err error)
 	ServeSettingsPage(ctx context.Context, c *model.Client) (err error)
+	SingleInstance(ctx context.Context) (instance string, ok bool)
 	NewSession(ctx context.Context, instance string) (redirectUrl string, sessionID string, err error)
 	Signin(ctx context.Context, c *model.Client, sessionID string,
 		code string) (token string, userID string, err error)
@@ -62,14 +63,15 @@ type Service interface {
 }
 
 type service struct {
-	clientName    string
-	clientScope   string
-	clientWebsite string
-	customCSS     string
-	postFormats   []model.PostFormat
-	renderer      renderer.Renderer
-	sessionRepo   model.SessionRepo
-	appRepo       model.AppRepo
+	clientName     string
+	clientScope    string
+	clientWebsite  string
+	customCSS      string
+	postFormats    []model.PostFormat
+	renderer       renderer.Renderer
+	sessionRepo    model.SessionRepo
+	appRepo        model.AppRepo
+	singleInstance string
 }
 
 func NewService(clientName string,
@@ -80,16 +82,18 @@ func NewService(clientName string,
 	renderer renderer.Renderer,
 	sessionRepo model.SessionRepo,
 	appRepo model.AppRepo,
+	singleInstance string,
 ) Service {
 	return &service{
-		clientName:    clientName,
-		clientScope:   clientScope,
-		clientWebsite: clientWebsite,
-		customCSS:     customCSS,
-		postFormats:   postFormats,
-		renderer:      renderer,
-		sessionRepo:   sessionRepo,
-		appRepo:       appRepo,
+		clientName:     clientName,
+		clientScope:    clientScope,
+		clientWebsite:  clientWebsite,
+		customCSS:      customCSS,
+		postFormats:    postFormats,
+		renderer:       renderer,
+		sessionRepo:    sessionRepo,
+		appRepo:        appRepo,
+		singleInstance: singleInstance,
 	}
 }
 
@@ -622,6 +626,14 @@ func (svc *service) ServeSettingsPage(ctx context.Context, c *model.Client) (err
 	return svc.renderer.Render(rCtx, c.Writer, renderer.SettingsPage, data)
 }
 
+func (svc *service) SingleInstance(ctx context.Context) (instance string, ok bool) {
+	if len(svc.singleInstance) > 0 {
+		instance = svc.singleInstance
+		ok = true
+	}
+	return
+}
+
 func (svc *service) NewSession(ctx context.Context, instance string) (
 	redirectUrl string, sessionID string, err error) {
 
diff --git a/service/transport.go b/service/transport.go
index 69b28ec..f52cca0 100644
--- a/service/transport.go
+++ b/service/transport.go
@@ -14,12 +14,24 @@ import (
 	"github.com/gorilla/mux"
 )
 
+const (
+	sessionExp = 365 * 24 * time.Hour
+)
+
 func newClient(w io.Writer) *model.Client {
 	return &model.Client{
 		Writer: w,
 	}
 }
 
+func setSessionCookie(w http.ResponseWriter, sessionID string, exp time.Duration) {
+	http.SetCookie(w, &http.Cookie{
+		Name:    "session_id",
+		Value:   sessionID,
+		Expires: time.Now().Add(exp),
+	})
+}
+
 func newCtxWithSesion(req *http.Request) context.Context {
 	ctx := context.Background()
 	sessionID, err := req.Cookie("session_id")
@@ -93,11 +105,25 @@ func NewHandler(s Service, staticDir string) http.Handler {
 	signinPage := func(w http.ResponseWriter, req *http.Request) {
 		c := newClient(w)
 		ctx := context.Background()
-		err := s.ServeSigninPage(ctx, c)
-		if err != nil {
-			w.WriteHeader(http.StatusInternalServerError)
-			s.ServeErrorPage(ctx, c, err)
-			return
+		instance, ok := s.SingleInstance(ctx)
+		if ok {
+			url, sessionID, err := s.NewSession(ctx, instance)
+			if err != nil {
+				w.WriteHeader(http.StatusInternalServerError)
+				s.ServeErrorPage(ctx, c, err)
+				return
+			}
+
+			setSessionCookie(w, sessionID, sessionExp)
+			w.Header().Add("Location", url)
+			w.WriteHeader(http.StatusFound)
+		} else {
+			err := s.ServeSigninPage(ctx, c)
+			if err != nil {
+				w.WriteHeader(http.StatusInternalServerError)
+				s.ServeErrorPage(ctx, c, err)
+				return
+			}
 		}
 	}
 
@@ -291,12 +317,7 @@ func NewHandler(s Service, staticDir string) http.Handler {
 			return
 		}
 
-		http.SetCookie(w, &http.Cookie{
-			Name:    "session_id",
-			Value:   sessionID,
-			Expires: time.Now().Add(365 * 24 * time.Hour),
-		})
-
+		setSessionCookie(w, sessionID, sessionExp)
 		w.Header().Add("Location", url)
 		w.WriteHeader(http.StatusFound)
 	}
@@ -689,12 +710,8 @@ func NewHandler(s Service, staticDir string) http.Handler {
 		ctx := newCtxWithSesionCSRF(req, req.FormValue("csrf_token"))
 
 		s.Signout(ctx, c)
-		http.SetCookie(w, &http.Cookie{
-			Name:    "session_id",
-			Value:   "",
-			Expires: time.Now(),
-		})
 
+		setSessionCookie(w, "", 0)
 		w.Header().Add("Location", "/")
 		w.WriteHeader(http.StatusFound)
 	}