Add unsubscribe functionality

db/channels.go

@@ -90,3 +90,19 @@ func (d *postgresDB) SubscribeUserToChannel(ctx context.Context, username string
 
 	return nil
 }
+
+var unsubscribeUserFromChannelQuery = `DELETE FROM user_subscriptions WHERE username = $1 AND channel_id = $2`
+
+func (d *postgresDB) UnsubscribeUserFromChannel(ctx context.Context, username string, channelID string) error {
+	resp, err := d.db.ExecContext(ctx, unsubscribeUserFromChannelQuery, username, channelID)
+	if err != nil {
+		d.l.Log("level", "ERROR", "function", "db.SubscribeUserToChannel", "error", err)
+		return err
+	}
+
+	if affected, err := resp.RowsAffected(); err != nil || affected != 1 {
+		return ErrChannelNotFound
+	}
+
+	return nil
+}

db/db.go

@@ -10,6 +10,7 @@ import (
 
 var (
 	ErrChannelExists     = errors.New("channel already exists")
+	ErrChannelNotFound   = errors.New("no channel with that ID found")
 	ErrAlreadySubscribed = errors.New("already subscribed to channel")
 	ErrVideoExists       = errors.New("video already exists")
 	ErrUserExists        = errors.New("user already exists")
@@ -30,8 +31,10 @@ type DB interface {
 	ListChannels(ctx context.Context) ([]models.Channel, error)
 	// GetChannelSubscribers lists all channels from the database
 	GetChannelSubscribers(ctx context.Context, channelID string) ([]string, error)
-	// SubscribeUserToChannel will start showing new videos for that channel to the user
+	// SubscribeUserToChannel will start adding new videos from that channel to the user
 	SubscribeUserToChannel(ctx context.Context, username string, channelID string) error
+	// SubscribeUserToChannel will stop adding videos from that channel to the user
+	UnsubscribeUserFromChannel(ctx context.Context, username string, channelID string) error
 
 	// GetNewVideos returns a list of unwatched videos from all subscribed channels
 	GetNewVideos(ctx context.Context, username string) ([]models.Video, error)

handler/channels.go

@@ -27,3 +27,7 @@ func (h *handler) SubscribeToChannel(ctx context.Context, username string, chann
 
 	return h.db.SubscribeUserToChannel(ctx, username, channelID)
 }
+
+func (h *handler) UnsubscribeFromChannel(ctx context.Context, username string, channelID string) error {
+	return h.db.UnsubscribeUserFromChannel(ctx, username, channelID)
+}

handler/handler.go

@@ -11,6 +11,7 @@ import (
 type Handler interface {
 	CreateUser(ctx context.Context, user models.User) error
 	SubscribeToChannel(ctx context.Context, username string, channelID string) error
+	UnsubscribeFromChannel(ctx context.Context, username string, channelID string) error
 	GetNewVideos(ctx context.Context, username string) ([]models.Video, error)
 	GetWatchedVideos(ctx context.Context, username string) ([]models.Video, error)
 	FetchVideos(ctx context.Context) error

httpserver/ytrssil/channels.go

@@ -37,3 +37,26 @@ func (s *server) SubscribeToChannel(c *gin.Context) {
 
 	c.JSON(http.StatusOK, gin.H{"msg": "subscribed to channel successfully"})
 }
+
+func (s *server) UnsubscribeFromChannel(c *gin.Context) {
+	var channel models.Channel
+	err := c.ShouldBindUri(&channel)
+	if err != nil {
+		c.AbortWithStatusJSON(http.StatusBadRequest, gin.H{"error": err.Error()})
+		return
+	}
+	username := c.GetString("username")
+
+	err = s.handler.UnsubscribeFromChannel(c.Request.Context(), username, channel.ID)
+	if err != nil {
+		if errors.Is(err, db.ErrChannelNotFound) {
+			c.AbortWithStatusJSON(http.StatusNotFound, gin.H{"error": err.Error()})
+			return
+		}
+
+		c.AbortWithStatusJSON(http.StatusInternalServerError, gin.H{"error": err.Error()})
+		return
+	}
+
+	c.JSON(http.StatusOK, gin.H{"msg": "unsubscribed from channel successfully"})
+}

httpserver/ytrssil/server.go

@@ -44,6 +44,7 @@ func SetupGinRouter(l log.Logger, handler handler.Handler, authMiddleware func(c
 	api.Use(authMiddleware)
 	{
 		api.POST("channels/:channel_id/subscribe", srv.SubscribeToChannel)
+		api.POST("channels/:channel_id/unsubscribe", srv.UnsubscribeFromChannel)
 		api.GET("videos/new", srv.GetNewVideos)
 		api.GET("videos/watched", srv.GetWatchedVideos)
 		api.POST("videos/:video_id/watch", srv.MarkVideoAsWatched)

mocks/db/db.go

@@ -57,6 +57,9 @@ var _ db.DB = &DBMock{}
 //			SubscribeUserToChannelFunc: func(ctx context.Context, username string, channelID string) error {
 //				panic("mock out the SubscribeUserToChannel method")
 //			},
+//			UnsubscribeUserFromChannelFunc: func(ctx context.Context, username string, channelID string) error {
+//				panic("mock out the UnsubscribeUserFromChannel method")
+//			},
 //		}
 //
 //		// use mockedDB in code that requires db.DB
@@ -100,6 +103,9 @@ type DBMock struct {
 	// SubscribeUserToChannelFunc mocks the SubscribeUserToChannel method.
 	SubscribeUserToChannelFunc func(ctx context.Context, username string, channelID string) error
 
+	// UnsubscribeUserFromChannelFunc mocks the UnsubscribeUserFromChannel method.
+	UnsubscribeUserFromChannelFunc func(ctx context.Context, username string, channelID string) error
+
 	// calls tracks calls to the methods.
 	calls struct {
 		// AddVideo holds details about calls to the AddVideo method.
@@ -194,6 +200,15 @@ type DBMock struct {
 			// ChannelID is the channelID argument value.
 			ChannelID string
 		}
+		// UnsubscribeUserFromChannel holds details about calls to the UnsubscribeUserFromChannel method.
+		UnsubscribeUserFromChannel []struct {
+			// Ctx is the ctx argument value.
+			Ctx context.Context
+			// Username is the username argument value.
+			Username string
+			// ChannelID is the channelID argument value.
+			ChannelID string
+		}
 	}
 	lockAddVideo                   sync.RWMutex
 	lockAddVideoToUser             sync.RWMutex
@@ -207,6 +222,7 @@ type DBMock struct {
 	lockListChannels               sync.RWMutex
 	lockSetVideoWatchTime          sync.RWMutex
 	lockSubscribeUserToChannel     sync.RWMutex
+	lockUnsubscribeUserFromChannel sync.RWMutex
 }
 
 // AddVideo calls AddVideoFunc.
@@ -656,3 +672,43 @@ func (mock *DBMock) SubscribeUserToChannelCalls() []struct {
 	mock.lockSubscribeUserToChannel.RUnlock()
 	return calls
 }
+
+// UnsubscribeUserFromChannel calls UnsubscribeUserFromChannelFunc.
+func (mock *DBMock) UnsubscribeUserFromChannel(ctx context.Context, username string, channelID string) error {
+	if mock.UnsubscribeUserFromChannelFunc == nil {
+		panic("DBMock.UnsubscribeUserFromChannelFunc: method is nil but DB.UnsubscribeUserFromChannel was just called")
+	}
+	callInfo := struct {
+		Ctx       context.Context
+		Username  string
+		ChannelID string
+	}{
+		Ctx:       ctx,
+		Username:  username,
+		ChannelID: channelID,
+	}
+	mock.lockUnsubscribeUserFromChannel.Lock()
+	mock.calls.UnsubscribeUserFromChannel = append(mock.calls.UnsubscribeUserFromChannel, callInfo)
+	mock.lockUnsubscribeUserFromChannel.Unlock()
+	return mock.UnsubscribeUserFromChannelFunc(ctx, username, channelID)
+}
+
+// UnsubscribeUserFromChannelCalls gets all the calls that were made to UnsubscribeUserFromChannel.
+// Check the length with:
+//
+//	len(mockedDB.UnsubscribeUserFromChannelCalls())
+func (mock *DBMock) UnsubscribeUserFromChannelCalls() []struct {
+	Ctx       context.Context
+	Username  string
+	ChannelID string
+} {
+	var calls []struct {
+		Ctx       context.Context
+		Username  string
+		ChannelID string
+	}
+	mock.lockUnsubscribeUserFromChannel.RLock()
+	calls = mock.calls.UnsubscribeUserFromChannel
+	mock.lockUnsubscribeUserFromChannel.RUnlock()
+	return calls
+}