Merge branch 'refs/heads/development' into 49-add-htwkarte-linkout-at-ics-event-info

# Conflicts:
#	services/ical/main.go
#	services/ical/service/ical/ical.go
#	services/ical/service/routes.go

services/ical/service/connector/grpc/client.go

@@ -19,14 +19,31 @@ package grpc
 import (
 	"google.golang.org/grpc"
 	"google.golang.org/grpc/credentials/insecure"
+	"google.golang.org/grpc/keepalive"
 	"log/slog"
+	"sync"
+	"time"
 )
 
+var conn *grpc.ClientConn
+var once sync.Once
+
 func ConnectGRPCServer(host string) *grpc.ClientConn {
-	conn, err := grpc.NewClient(host+":50051", grpc.WithTransportCredentials(insecure.NewCredentials()))
-	if err != nil {
-		slog.Error("could not connect to grpc server", "error", err)
-	}
+	once.Do(func() {
+		var err error
+		conn, err = grpc.NewClient(
+			host+":50051",
+			grpc.WithTransportCredentials(insecure.NewCredentials()),
+			grpc.WithKeepaliveParams(keepalive.ClientParameters{
+				Time:                2 * time.Minute,
+				Timeout:             20 * time.Second,
+				PermitWithoutStream: true,
+			}),
+		)
+		if err != nil {
+			slog.Error("could not connect to grpc server", "error", err)
+		}
+	})
 	return conn
 }
 

services/ical/service/ical/ical.go

@@ -21,6 +21,7 @@ import (
 	"htwkalender/ical/model"
 	"htwkalender/ical/service/connector"
 	htwkalenderGrpc "htwkalender/ical/service/connector/grpc"
+	"htwkalender/ical/service/functions"
 	"log/slog"
 	"time"
 )
@@ -29,7 +30,7 @@ const expirationTime = 5 * time.Minute
 
 var FeedDeletedError = fmt.Errorf("feed deleted")
 
-func Feed(app model.AppType, token string, userAgent string) (string, error) {
+func Feed(app model.AppType, token string, userAgent string) (string, string, error) {
 
 	var events model.Events
 	modules := map[string]model.FeedCollection{}
@@ -45,17 +46,17 @@ func Feed(app model.AppType, token string, userAgent string) (string, error) {
 		// get feed by token
 		feed, err := htwkalenderGrpc.GetFeed(token, app.GrpcClient)
 		if err != nil {
-			return "", err
+			return "", "", err
 		}
 
 		if feed.Deleted {
-			return "", FeedDeletedError
+			return "", "", FeedDeletedError
 		}
 
 		// Get all events for modules
 		events, err = htwkalenderGrpc.GetEvents(feed.Modules, app.GrpcClient)
 		if err != nil {
-			return "", err
+			return "", "", err
 		}
 
 		// Sort events by start date
@@ -66,10 +67,13 @@ func Feed(app model.AppType, token string, userAgent string) (string, error) {
 		}
 	}
 
+	// Generate one Hash for E-TAG from all events and modules
+	etag := functions.HashString(events.String() + fmt.Sprint(modules))
+
 	cal := GenerateIcalFeed(events, modules, userAgent)
 	icalFeed := &model.FeedModel{Content: cal.Serialize(), ExpiresAt: model.JSONTime(time.Now().Add(expirationTime))}
 
-	return icalFeed.Content, nil
+	return icalFeed.Content, etag, nil
 }
 
 func FeedRecord(app model.AppType, token string) (model.FeedRecord, error) {

services/ical/service/routes.go

@@ -34,13 +34,12 @@ func AddFeedRoutes(app model.AppType) {
 	app.Fiber.Get("/api/feed", func(c fiber.Ctx) error {
 
 		token := c.Query("token")
-
+		ifNoneMatch := c.Get("If-None-Match")
 		// get request userAgent and check if it is Thunderbird
 		userAgent := c.Get("User-Agent")
-
 		slog.Info("User-Agent", "userAgent", userAgent)
 
-		results, err := ical.Feed(app, token, userAgent)
+		results, eTag, err := ical.Feed(app, token, userAgent)
 
 		if errors.Is(err, ical.FeedDeletedError) {
 			return c.SendStatus(fiber.StatusGone)
@@ -50,10 +49,16 @@ func AddFeedRoutes(app model.AppType) {
 			slog.Error("Failed to get feed", "error", err, "token", token)
 			return c.SendStatus(fiber.StatusNotFound)
 		}
+
+		if ifNoneMatch == eTag && ifNoneMatch != "" {
+			return c.SendStatus(fiber.StatusNotModified)
+		}
+
 		c.Response().Header.Set("Content-type", "text/calendar")
 		c.Response().Header.Set("charset", "utf-8")
 		c.Response().Header.Set("Content-Disposition", "inline")
 		c.Response().Header.Set("filename", "calendar.ics")
+		c.Response().Header.Set("ETag", eTag)
 
 		return c.SendString(results)
 	})