Speedup pubilc courses rpc

apiv2/helpers/parser.go

@@ -55,12 +55,23 @@ func ParseBookmarkToProto(b model.Bookmark) *protobuf.Bookmark {
 	}
 }
 
+// ParseCourseSummaryToProto converts a course to the reduced representation used
+// on list pages. It intentionally skips signed playlist URLs and download payloads,
+// because those are only needed on player/detail pages.
+func ParseCourseSummaryToProto(c model.Course, u *model.User) *protobuf.Course {
+	return parseCourseToProto(c, u, false, false)
+}
+
 // ParseCourseToProto converts a Course model to its protobuf representation.
 //
 // Everything derived here is derived for u: the private lectures of a course the
 // caller does not administer are left out of the last recording and the next lecture,
 // and the pin is the caller's own.
 func ParseCourseToProto(c model.Course, u *model.User) *protobuf.Course {
+	return parseCourseToProto(c, u, true, true)
+}
+
+func parseCourseToProto(c model.Course, u *model.User, signPlaylists bool, includeDownloads bool) *protobuf.Course {
 	course := &protobuf.Course{
 		Id:   uint32(c.ID),
 		Name: c.Name,
@@ -87,10 +98,10 @@ func ParseCourseToProto(c model.Course, u *model.User) *protobuf.Course {
 	// absent rather than sent as a stream with id 0, which every caller would then
 	// have to know to test for — as the Alpine start page did.
 	if last := c.GetLastRecording(u); last.ID != 0 {
-		course.LastRecording = ParseStreamToProto(*last, c, u)
+		course.LastRecording = parseStreamToProto(*last, c, u, signPlaylists, includeDownloads)
 	}
 	if next := c.GetNextLecture(u); next.ID != 0 {
-		course.NextLecture = ParseStreamToProto(*next, c, u)
+		course.NextLecture = parseStreamToProto(*next, c, u, signPlaylists, includeDownloads)
 	}
 
 	return course
@@ -122,9 +133,19 @@ func ParseSemesterToProto(semester model.Semester) *protobuf.Semester {
 
 // ParseStreamToProto converts a Stream model to its protobuf representation.
 func ParseStreamToProto(stream model.Stream, course model.Course, user *model.User) *protobuf.Stream {
+	return parseStreamToProto(stream, course, user, true, true)
+}
+
+func ParseStreamSummaryToProto(stream model.Stream, course model.Course, user *model.User) *protobuf.Stream {
+	return parseStreamToProto(stream, course, user, false, false)
+}
+
+func parseStreamToProto(stream model.Stream, course model.Course, user *model.User, signPlaylists bool, includeDownloads bool) *protobuf.Stream {
 	liveNow := stream.LiveNowTimestamp.After(time.Now())
 
-	_ = tools.SetSignedPlaylists(&stream, user, course.DownloadsEnabled)
+	if signPlaylists {
+		_ = tools.SetSignedPlaylists(&stream, user, course.DownloadsEnabled)
+	}
 
 	s := &protobuf.Stream{
 		Id:               uint32(stream.ID),
@@ -169,7 +190,7 @@ func ParseStreamToProto(stream model.Stream, course model.Course, user *model.Us
 		s.Duration = uint32(duration)
 	}
 
-	if course.DownloadsEnabled {
+	if includeDownloads && course.DownloadsEnabled {
 		for _, download := range stream.GetVodFiles() {
 			s.Downloads = append(s.Downloads, ParseDownloadToProto(download))
 		}

apiv2/server/course.go

@@ -4,7 +4,9 @@ package apiv2
 import (
 	"context"
 	"errors"
+	"fmt"
 	"net/http"
+	"time"
 
 	"github.com/RBG-TUM/commons"
 	"google.golang.org/protobuf/types/known/emptypb"
@@ -14,6 +16,7 @@ import (
 	h "github.com/TUM-Dev/gocast/apiv2/helpers"
 	protobuf "github.com/TUM-Dev/gocast/apiv2/protobuf/server"
 	"github.com/TUM-Dev/gocast/apiv2/visibility"
+	"github.com/TUM-Dev/gocast/dao"
 	"github.com/TUM-Dev/gocast/model"
 	"github.com/TUM-Dev/gocast/tools/tum"
 )
@@ -106,6 +109,13 @@ func (a *API) GetPublicCourses(ctx context.Context, req *protobuf.GetPublicCours
 		term = req.Term
 	}
 
+	if user == nil {
+		key := fmt.Sprintf("publicCoursesSummary-%d-%s", year, term)
+		if cached, ok := dao.Cache.Get(key); ok {
+			return &protobuf.GetPublicCoursesResponse{Courses: cached.([]*protobuf.Course)}, nil
+		}
+	}
+
 	var courses []model.Course
 
 	if user != nil {
@@ -119,7 +129,15 @@ func (a *API) GetPublicCourses(ctx context.Context, req *protobuf.GetPublicCours
 
 	resp := make([]*protobuf.Course, len(courses))
 	for i, course := range courses {
-		resp[i] = h.ParseCourseToProto(course, user)
+		if user == nil {
+			resp[i] = h.ParseCourseSummaryToProto(course, user)
+		} else {
+			resp[i] = h.ParseCourseToProto(course, user)
+		}
+	}
+
+	if user == nil {
+		dao.Cache.SetWithTTL(fmt.Sprintf("publicCoursesSummary-%d-%s", year, term), resp, 1, 6*time.Hour)
 	}
 
 	return &protobuf.GetPublicCoursesResponse{Courses: resp}, nil

dao/courses.go

@@ -50,6 +50,17 @@ type CoursesDaoImpl struct {
 	usersDao UsersDao
 }
 
+func publicCourseStreamFilter() func(*gorm.DB) *gorm.DB {
+	latestRecording := DB.Model(&model.Stream{}).
+		Select("MAX(start)").
+		Where("course_id = streams.course_id AND recording = ?", true)
+
+	return func(db *gorm.DB) *gorm.DB {
+		return db.Where("(recording = ? AND start = (?)) OR start > NOW()", true, latestRecording).
+			Order("start asc")
+	}
+}
+
 func NewCoursesDao() CoursesDaoImpl {
 	return CoursesDaoImpl{db: DB, usersDao: NewUsersDao()}
 }
@@ -161,9 +172,8 @@ func (d CoursesDaoImpl) GetPublicCourses(year int, term string) (courses []model
 	}
 	var publicCourses []model.Course
 
-	err = DB.Preload("Streams", func(db *gorm.DB) *gorm.DB {
-		return db.Order("start asc")
-	}).Find(&publicCourses, "visibility = 'public' AND teaching_term = ? AND year = ?",
+	err = DB.Preload("Streams", publicCourseStreamFilter()).Find(&publicCourses,
+		"visibility = 'public' AND teaching_term = ? AND year = ?",
 		term, year).Error
 
 	if err == nil {
@@ -179,9 +189,7 @@ func (d CoursesDaoImpl) GetPublicAndLoggedInCourses(year int, term string) (cour
 	}
 	var publicCourses []model.Course
 
-	err = DB.Preload("Streams", func(db *gorm.DB) *gorm.DB {
-		return db.Order("start asc")
-	}).Find(&publicCourses,
+	err = DB.Preload("Streams", publicCourseStreamFilter()).Find(&publicCourses,
 		"(visibility = 'public' OR visibility = 'loggedin') AND teaching_term = ? AND year = ?", term, year).Error
 	if err == nil {
 		Cache.SetWithTTL(fmt.Sprintf("publicAndLoggedInCourses%d%v", year, term), publicCourses, 1, time.Minute)

dao/courses_test.go

@@ -0,0 +1 @@
+package dao