PLT-5012 Combine updateLastViewedAt, setLastViewedAt and setActiveChannel into a single API (#4840)

* Combine updateLastViewedAt, setLastViewedAt and setActiveChannel into a single API

* Remove preference DB writes

17 files changed, 386 insertions, 276 deletions

diff --git a/api/channel.go b/api/channel.go
index 941692ac3..feebf6981 100644
--- a/api/channel.go
+++ b/api/channel.go
@@ -25,6 +25,7 @@ func InitChannel() {
 	BaseRoutes.Channels.Handle("/counts", ApiUserRequired(getChannelCounts)).Methods("GET")
 	BaseRoutes.Channels.Handle("/members", ApiUserRequired(getMyChannelMembers)).Methods("GET")
 	BaseRoutes.Channels.Handle("/create", ApiUserRequired(createChannel)).Methods("POST")
+	BaseRoutes.Channels.Handle("/view", ApiUserRequired(viewChannel)).Methods("POST")
 	BaseRoutes.Channels.Handle("/create_direct", ApiUserRequired(createDirectChannel)).Methods("POST")
 	BaseRoutes.Channels.Handle("/update", ApiUserRequired(updateChannel)).Methods("POST")
 	BaseRoutes.Channels.Handle("/update_header", ApiUserRequired(updateChannelHeader)).Methods("POST")
@@ -43,9 +44,6 @@ func InitChannel() {
 	BaseRoutes.NeedChannel.Handle("/delete", ApiUserRequired(deleteChannel)).Methods("POST")
 	BaseRoutes.NeedChannel.Handle("/add", ApiUserRequired(addMember)).Methods("POST")
 	BaseRoutes.NeedChannel.Handle("/remove", ApiUserRequired(removeMember)).Methods("POST")
-	BaseRoutes.NeedChannel.Handle("/update_last_viewed_at", ApiUserRequired(updateLastViewedAt)).Methods("POST")
-	BaseRoutes.NeedChannel.Handle("/set_last_viewed_at", ApiUserRequired(setLastViewedAt)).Methods("POST")
-
 }
 
 func createChannel(c *Context, w http.ResponseWriter, r *http.Request) {
@@ -873,103 +871,6 @@ func deleteChannel(c *Context, w http.ResponseWriter, r *http.Request) {
 	}
 }
 
-func setLastViewedAt(c *Context, w http.ResponseWriter, r *http.Request) {
-	params := mux.Vars(r)
-	id := params["channel_id"]
-
-	data := model.StringInterfaceFromJson(r.Body)
-	newLastViewedAt := int64(data["last_viewed_at"].(float64))
-
-	Srv.Store.Channel().SetLastViewedAt(id, c.Session.UserId, newLastViewedAt)
-
-	chanPref := model.Preference{
-		UserId:   c.Session.UserId,
-		Category: c.TeamId,
-		Name:     model.PREFERENCE_NAME_LAST_CHANNEL,
-		Value:    id,
-	}
-
-	teamPref := model.Preference{
-		UserId:   c.Session.UserId,
-		Category: model.PREFERENCE_CATEGORY_LAST,
-		Name:     model.PREFERENCE_NAME_LAST_TEAM,
-		Value:    c.TeamId,
-	}
-
-	Srv.Store.Preference().Save(&model.Preferences{teamPref, chanPref})
-
-	message := model.NewWebSocketEvent(model.WEBSOCKET_EVENT_CHANNEL_VIEWED, c.TeamId, "", c.Session.UserId, nil)
-	message.Add("channel_id", id)
-
-	go Publish(message)
-
-	result := make(map[string]string)
-	result["id"] = id
-	w.Write([]byte(model.MapToJson(result)))
-}
-
-func updateLastViewedAt(c *Context, w http.ResponseWriter, r *http.Request) {
-	params := mux.Vars(r)
-	id := params["channel_id"]
-
-	data := model.StringInterfaceFromJson(r.Body)
-
-	var active bool
-	var ok bool
-	if active, ok = data["active"].(bool); !ok {
-		active = true
-	}
-
-	doClearPush := false
-	if *utils.Cfg.EmailSettings.SendPushNotifications && !c.Session.IsMobileApp() && active {
-		if result := <-Srv.Store.User().GetUnreadCountForChannel(c.Session.UserId, id); result.Err != nil {
-			l4g.Error(utils.T("api.channel.update_last_viewed_at.get_unread_count_for_channel.error"), c.Session.UserId, id, result.Err.Error())
-		} else {
-			if result.Data.(int64) > 0 {
-				doClearPush = true
-			}
-		}
-	}
-
-	go func() {
-		if err := SetActiveChannel(c.Session.UserId, id); err != nil {
-			l4g.Error(err.Error())
-		}
-	}()
-
-	Srv.Store.Channel().UpdateLastViewedAt(id, c.Session.UserId)
-
-	// Must be after update so that unread count is correct
-	if doClearPush {
-		go clearPushNotification(c.Session.UserId, id)
-	}
-
-	chanPref := model.Preference{
-		UserId:   c.Session.UserId,
-		Category: c.TeamId,
-		Name:     model.PREFERENCE_NAME_LAST_CHANNEL,
-		Value:    id,
-	}
-
-	teamPref := model.Preference{
-		UserId:   c.Session.UserId,
-		Category: model.PREFERENCE_CATEGORY_LAST,
-		Name:     model.PREFERENCE_NAME_LAST_TEAM,
-		Value:    c.TeamId,
-	}
-
-	Srv.Store.Preference().Save(&model.Preferences{teamPref, chanPref})
-
-	message := model.NewWebSocketEvent(model.WEBSOCKET_EVENT_CHANNEL_VIEWED, c.TeamId, "", c.Session.UserId, nil)
-	message.Add("channel_id", id)
-
-	go Publish(message)
-
-	result := make(map[string]string)
-	result["id"] = id
-	w.Write([]byte(model.MapToJson(result)))
-}
-
 func getChannel(c *Context, w http.ResponseWriter, r *http.Request) {
 	params := mux.Vars(r)
 	id := params["channel_id"]
@@ -1001,7 +902,27 @@ func getChannel(c *Context, w http.ResponseWriter, r *http.Request) {
 			w.Write([]byte(data.ToJson()))
 		}
 	}
+}
+
+func SetActiveChannel(userId string, channelId string) *model.AppError {
+	status, err := GetStatus(userId)
+	if err != nil {
+		status = &model.Status{userId, model.STATUS_ONLINE, false, model.GetMillis(), channelId}
+	} else {
+		status.ActiveChannel = channelId
+		if !status.Manual {
+			status.Status = model.STATUS_ONLINE
+		}
+		status.LastActivityAt = model.GetMillis()
+	}
+
+	AddStatusCache(status)
+
+	if result := <-Srv.Store.Status().SaveOrUpdate(status); result.Err != nil {
+		return result.Err
+	}
 
+	return nil
 }
 
 func getChannelByName(c *Context, w http.ResponseWriter, r *http.Request) {
@@ -1332,3 +1253,50 @@ func autocompleteChannels(c *Context, w http.ResponseWriter, r *http.Request) {
 
 	w.Write([]byte(channels.ToJson()))
 }
+
+func viewChannel(c *Context, w http.ResponseWriter, r *http.Request) {
+	view := model.ChannelViewFromJson(r.Body)
+
+	go func() {
+		if err := SetActiveChannel(c.Session.UserId, view.ChannelId); err != nil {
+			l4g.Error(err.Error())
+		}
+	}()
+
+	if len(view.ChannelId) > 0 {
+
+		if view.Time == 0 {
+			if result := <-Srv.Store.Channel().UpdateLastViewedAt(view.ChannelId, c.Session.UserId); result.Err != nil {
+				c.Err = result.Err
+				return
+			}
+		} else {
+			if result := <-Srv.Store.Channel().SetLastViewedAt(view.ChannelId, c.Session.UserId, view.Time); result.Err != nil {
+				c.Err = result.Err
+				return
+			}
+		}
+
+		if len(view.PrevChannelId) > 0 {
+			Srv.Store.Channel().UpdateLastViewedAt(view.PrevChannelId, c.Session.UserId)
+
+			// Only clear push notifications if a channel switch occured
+			if *utils.Cfg.EmailSettings.SendPushNotifications && !c.Session.IsMobileApp() {
+				go func() {
+					if result := <-Srv.Store.User().GetUnreadCountForChannel(c.Session.UserId, view.ChannelId); result.Err != nil {
+						l4g.Error(utils.T("api.channel.update_last_viewed_at.get_unread_count_for_channel.error"), c.Session.UserId, view.ChannelId, result.Err.Error())
+					} else {
+						if result.Data.(int64) > 0 {
+							clearPushNotification(c.Session.UserId, view.ChannelId)
+						}
+					}
+				}()
+			}
+		}
+
+		message := model.NewWebSocketEvent(model.WEBSOCKET_EVENT_CHANNEL_VIEWED, c.TeamId, "", c.Session.UserId, nil)
+		message.Add("channel_id", view.ChannelId)
+	}
+
+	ReturnStatusOK(w)
+}
diff --git a/api/channel_test.go b/api/channel_test.go
index ae4573c9c..d24a6d603 100644
--- a/api/channel_test.go
+++ b/api/channel_test.go
@@ -724,8 +724,9 @@ func TestGetChannel(t *testing.T) {
 		t.Fatal("cache should be empty")
 	}
 
-	if _, err := Client.UpdateLastViewedAt(channel2.Id, true); err != nil {
-		t.Fatal(err)
+	view := model.ChannelView{ChannelId: channel2.Id, PrevChannelId: channel1.Id}
+	if _, resp := Client.ViewChannel(view); resp.Error != nil {
+		t.Fatal(resp.Error)
 	}
 
 	if resp, err := Client.GetChannel(channel1.Id, ""); err != nil {
@@ -1735,3 +1736,44 @@ func TestGetChannelByName(t *testing.T) {
 		t.Fatal("Should fail due to not enough permissions")
 	}
 }
+
+func TestViewChannel(t *testing.T) {
+	th := Setup().InitBasic()
+	Client := th.BasicClient
+
+	view := model.ChannelView{
+		ChannelId: th.BasicChannel.Id,
+	}
+
+	if _, resp := Client.ViewChannel(view); resp.Error != nil {
+		t.Fatal(resp.Error)
+	}
+
+	view.PrevChannelId = th.BasicChannel.Id
+
+	if _, resp := Client.ViewChannel(view); resp.Error != nil {
+		t.Fatal(resp.Error)
+	}
+
+	view.PrevChannelId = ""
+	view.Time = 1234567890
+
+	if _, resp := Client.ViewChannel(view); resp.Error != nil {
+		t.Fatal(resp.Error)
+	}
+
+	view.PrevChannelId = "junk"
+	view.Time = 0
+
+	if _, resp := Client.ViewChannel(view); resp.Error != nil {
+		t.Fatal(resp.Error)
+	}
+
+	rdata := Client.Must(Client.GetChannel(th.BasicChannel.Id, "")).Data.(*model.ChannelData)
+
+	if rdata.Channel.TotalMsgCount != rdata.Member.MsgCount {
+		t.Log(rdata.Channel.TotalMsgCount)
+		t.Log(rdata.Member.MsgCount)
+		t.Fatal("message counts don't match")
+	}
+}
diff --git a/api/deprecated.go b/api/deprecated.go
index 427abdedf..183552414 100644
--- a/api/deprecated.go
+++ b/api/deprecated.go
@@ -7,6 +7,7 @@ import (
 	"net/http"
 
 	l4g "github.com/alecthomas/log4go"
+	"github.com/gorilla/mux"
 	"github.com/mattermost/platform/model"
 	"github.com/mattermost/platform/utils"
 )
@@ -16,7 +17,15 @@ import (
 func InitDeprecated() {
 	l4g.Debug(utils.T("api.channel.init.debug"))
 
-	BaseRoutes.Channels.Handle("/more", ApiUserRequired(getMoreChannels)).Methods("GET") // SCHEDULED FOR DEPRECATION IN 3.7
+	/* start - SCHEDULED FOR DEPRECATION IN 3.7 */
+	BaseRoutes.Channels.Handle("/more", ApiUserRequired(getMoreChannels)).Methods("GET")
+	/* end - SCHEDULED FOR DEPRECATION IN 3.7 */
+
+	/* start - SCHEDULED FOR DEPRECATION IN 3.8 */
+	BaseRoutes.NeedChannel.Handle("/update_last_viewed_at", ApiUserRequired(updateLastViewedAt)).Methods("POST")
+	BaseRoutes.NeedChannel.Handle("/set_last_viewed_at", ApiUserRequired(setLastViewedAt)).Methods("POST")
+	BaseRoutes.Users.Handle("/status/set_active_channel", ApiUserRequired(setActiveChannel)).Methods("POST")
+	/* end - SCHEDULED FOR DEPRECATION IN 3.8 */
 }
 
 func getMoreChannels(c *Context, w http.ResponseWriter, r *http.Request) {
@@ -37,3 +46,118 @@ func getMoreChannels(c *Context, w http.ResponseWriter, r *http.Request) {
 		w.Write([]byte(data.ToJson()))
 	}
 }
+
+func updateLastViewedAt(c *Context, w http.ResponseWriter, r *http.Request) {
+	params := mux.Vars(r)
+	id := params["channel_id"]
+
+	data := model.StringInterfaceFromJson(r.Body)
+
+	var active bool
+	var ok bool
+	if active, ok = data["active"].(bool); !ok {
+		active = true
+	}
+
+	doClearPush := false
+	if *utils.Cfg.EmailSettings.SendPushNotifications && !c.Session.IsMobileApp() && active {
+		if result := <-Srv.Store.User().GetUnreadCountForChannel(c.Session.UserId, id); result.Err != nil {
+			l4g.Error(utils.T("api.channel.update_last_viewed_at.get_unread_count_for_channel.error"), c.Session.UserId, id, result.Err.Error())
+		} else {
+			if result.Data.(int64) > 0 {
+				doClearPush = true
+			}
+		}
+	}
+
+	go func() {
+		if err := SetActiveChannel(c.Session.UserId, id); err != nil {
+			l4g.Error(err.Error())
+		}
+	}()
+
+	Srv.Store.Channel().UpdateLastViewedAt(id, c.Session.UserId)
+
+	// Must be after update so that unread count is correct
+	if doClearPush {
+		go clearPushNotification(c.Session.UserId, id)
+	}
+
+	chanPref := model.Preference{
+		UserId:   c.Session.UserId,
+		Category: c.TeamId,
+		Name:     model.PREFERENCE_NAME_LAST_CHANNEL,
+		Value:    id,
+	}
+
+	teamPref := model.Preference{
+		UserId:   c.Session.UserId,
+		Category: model.PREFERENCE_CATEGORY_LAST,
+		Name:     model.PREFERENCE_NAME_LAST_TEAM,
+		Value:    c.TeamId,
+	}
+
+	Srv.Store.Preference().Save(&model.Preferences{teamPref, chanPref})
+
+	message := model.NewWebSocketEvent(model.WEBSOCKET_EVENT_CHANNEL_VIEWED, c.TeamId, "", c.Session.UserId, nil)
+	message.Add("channel_id", id)
+
+	go Publish(message)
+
+	result := make(map[string]string)
+	result["id"] = id
+	w.Write([]byte(model.MapToJson(result)))
+}
+
+func setLastViewedAt(c *Context, w http.ResponseWriter, r *http.Request) {
+	params := mux.Vars(r)
+	id := params["channel_id"]
+
+	data := model.StringInterfaceFromJson(r.Body)
+	newLastViewedAt := int64(data["last_viewed_at"].(float64))
+
+	Srv.Store.Channel().SetLastViewedAt(id, c.Session.UserId, newLastViewedAt)
+
+	chanPref := model.Preference{
+		UserId:   c.Session.UserId,
+		Category: c.TeamId,
+		Name:     model.PREFERENCE_NAME_LAST_CHANNEL,
+		Value:    id,
+	}
+
+	teamPref := model.Preference{
+		UserId:   c.Session.UserId,
+		Category: model.PREFERENCE_CATEGORY_LAST,
+		Name:     model.PREFERENCE_NAME_LAST_TEAM,
+		Value:    c.TeamId,
+	}
+
+	Srv.Store.Preference().Save(&model.Preferences{teamPref, chanPref})
+
+	message := model.NewWebSocketEvent(model.WEBSOCKET_EVENT_CHANNEL_VIEWED, c.TeamId, "", c.Session.UserId, nil)
+	message.Add("channel_id", id)
+
+	go Publish(message)
+
+	result := make(map[string]string)
+	result["id"] = id
+	w.Write([]byte(model.MapToJson(result)))
+}
+
+func setActiveChannel(c *Context, w http.ResponseWriter, r *http.Request) {
+	data := model.MapFromJson(r.Body)
+
+	var channelId string
+	var ok bool
+	if channelId, ok = data["channel_id"]; !ok || len(channelId) > 26 {
+		c.SetInvalidParam("setActiveChannel", "channel_id")
+		return
+	}
+
+	if err := SetActiveChannel(c.Session.UserId, channelId); err != nil {
+		c.Err = err
+		return
+	}
+
+	ReturnStatusOK(w)
+}
diff --git a/api/deprecated_test.go b/api/deprecated_test.go
index 000b3950d..ee2ce0b2c 100644
--- a/api/deprecated_test.go
+++ b/api/deprecated_test.go
@@ -41,3 +41,44 @@ func TestGetMoreChannel(t *testing.T) {
 		t.Fatal("cache should be empty")
 	}
 }
+
+/*
+func TestSetActiveChannel(t *testing.T) {
+	th := Setup().InitBasic()
+	Client := th.BasicClient
+
+	if _, err := Client.SetActiveChannel(th.BasicChannel.Id); err != nil {
+		t.Fatal(err)
+	}
+
+	status, _ := GetStatus(th.BasicUser.Id)
+	if status.ActiveChannel != th.BasicChannel.Id {
+		t.Fatal("active channel should be set")
+	}
+
+	if _, err := Client.SetActiveChannel(""); err != nil {
+		t.Fatal(err)
+	}
+
+	status, _ = GetStatus(th.BasicUser.Id)
+	if status.ActiveChannel != "" {
+		t.Fatal("active channel should be blank")
+	}
+
+	if _, err := Client.SetActiveChannel("123456789012345678901234567890"); err == nil {
+		t.Fatal("should have failed, id too long")
+	}
+
+	if _, err := Client.UpdateLastViewedAt(th.BasicChannel.Id, true); err != nil {
+		t.Fatal(err)
+	}
+
+	time.Sleep(500 * time.Millisecond)
+
+	status, _ = GetStatus(th.BasicUser.Id)
+	 need to check if offline to catch race
+	if status.Status != model.STATUS_OFFLINE && status.ActiveChannel != th.BasicChannel.Id {
+		t.Fatal("active channel should be set")
+	}
+}
+*/
diff --git a/api/status.go b/api/status.go
index a0ad4cd76..99d5bc417 100644
--- a/api/status.go
+++ b/api/status.go
@@ -37,7 +37,6 @@ func InitStatus() {
 
 	BaseRoutes.Users.Handle("/status", ApiUserRequired(getStatusesHttp)).Methods("GET")
 	BaseRoutes.Users.Handle("/status/ids", ApiUserRequired(getStatusesByIdsHttp)).Methods("POST")
-	BaseRoutes.Users.Handle("/status/set_active_channel", ApiUserRequired(setActiveChannel)).Methods("POST")
 	BaseRoutes.WebSocket.Handle("get_statuses", ApiWebSocketHandler(getStatusesWebSocket))
 	BaseRoutes.WebSocket.Handle("get_statuses_by_ids", ApiWebSocketHandler(getStatusesByIdsWebSocket))
 }
@@ -305,42 +304,3 @@ func DoesStatusAllowPushNotification(user *model.User, status *model.Status, cha
 
 	return false
 }
-
-func setActiveChannel(c *Context, w http.ResponseWriter, r *http.Request) {
-	data := model.MapFromJson(r.Body)
-
-	var channelId string
-	var ok bool
-	if channelId, ok = data["channel_id"]; !ok || len(channelId) > 26 {
-		c.SetInvalidParam("setActiveChannel", "channel_id")
-		return
-	}
-
-	if err := SetActiveChannel(c.Session.UserId, channelId); err != nil {
-		c.Err = err
-		return
-	}
-
-	ReturnStatusOK(w)
-}
-
-func SetActiveChannel(userId string, channelId string) *model.AppError {
-	status, err := GetStatus(userId)
-	if err != nil {
-		status = &model.Status{userId, model.STATUS_ONLINE, false, model.GetMillis(), channelId}
-	} else {
-		status.ActiveChannel = channelId
-		if !status.Manual {
-			status.Status = model.STATUS_ONLINE
-		}
-		status.LastActivityAt = model.GetMillis()
-	}
-
-	AddStatusCache(status)
-
-	if result := <-Srv.Store.Status().SaveOrUpdate(status); result.Err != nil {
-		return result.Err
-	}
-
-	return nil
-}
diff --git a/api/status_test.go b/api/status_test.go
index 2cf8c624b..5db5a8d7c 100644
--- a/api/status_test.go
+++ b/api/status_test.go
@@ -229,44 +229,3 @@ func TestGetStatusesByIds(t *testing.T) {
 		t.Fatal("should have errored")
 	}
 }
-
-/*
-func TestSetActiveChannel(t *testing.T) {
-	th := Setup().InitBasic()
-	Client := th.BasicClient
-
-	if _, err := Client.SetActiveChannel(th.BasicChannel.Id); err != nil {
-		t.Fatal(err)
-	}
-
-	status, _ := GetStatus(th.BasicUser.Id)
-	if status.ActiveChannel != th.BasicChannel.Id {
-		t.Fatal("active channel should be set")
-	}
-
-	if _, err := Client.SetActiveChannel(""); err != nil {
-		t.Fatal(err)
-	}
-
-	status, _ = GetStatus(th.BasicUser.Id)
-	if status.ActiveChannel != "" {
-		t.Fatal("active channel should be blank")
-	}
-
-	if _, err := Client.SetActiveChannel("123456789012345678901234567890"); err == nil {
-		t.Fatal("should have failed, id too long")
-	}
-
-	if _, err := Client.UpdateLastViewedAt(th.BasicChannel.Id, true); err != nil {
-		t.Fatal(err)
-	}
-
-	time.Sleep(500 * time.Millisecond)
-
-	status, _ = GetStatus(th.BasicUser.Id)
-	 need to check if offline to catch race
-	if status.Status != model.STATUS_OFFLINE && status.ActiveChannel != th.BasicChannel.Id {
-		t.Fatal("active channel should be set")
-	}
-}
-*/
diff --git a/model/channel_view.go b/model/channel_view.go
new file mode 100644
index 000000000..9803c4bbc
--- /dev/null
+++ b/model/channel_view.go
@@ -0,0 +1,35 @@
+// Copyright (c) 2016 Mattermost, Inc. All Rights Reserved.
+// See License.txt for license information.
+
+package model
+
+import (
+	"encoding/json"
+	"io"
+)
+
+type ChannelView struct {
+	ChannelId     string `json:"channel_id"`
+	PrevChannelId string `json:"prev_channel_id"`
+	Time          int64  `json:"time"`
+}
+
+func (o *ChannelView) ToJson() string {
+	b, err := json.Marshal(o)
+	if err != nil {
+		return ""
+	} else {
+		return string(b)
+	}
+}
+
+func ChannelViewFromJson(data io.Reader) *ChannelView {
+	decoder := json.NewDecoder(data)
+	var o ChannelView
+	err := decoder.Decode(&o)
+	if err == nil {
+		return &o
+	} else {
+		return nil
+	}
+}
diff --git a/model/client.go b/model/client.go
index e5f5fcea4..9ff34f5bf 100644
--- a/model/client.go
+++ b/model/client.go
@@ -48,6 +48,13 @@ type Result struct {
 	Data      interface{}
 }
 
+type ResponseMetadata struct {
+	StatusCode int
+	Error      *AppError
+	RequestId  string
+	Etag       string
+}
+
 type Client struct {
 	Url           string       // The location of the server like "http://localhost:8065"
 	ApiUrl        string       // The api location of the server like "http://localhost:8065/api/v3"
@@ -1329,6 +1336,7 @@ func (c *Client) RemoveChannelMember(id, user_id string) (*Result, *AppError) {
 // UpdateLastViewedAt will mark a channel as read.
 // The channelId indicates the channel to mark as read. If active is true, push notifications
 // will be cleared if there are unread messages. The default for active is true.
+// SCHEDULED FOR DEPRECATION IN 3.8 - use ViewChannel instead
 func (c *Client) UpdateLastViewedAt(channelId string, active bool) (*Result, *AppError) {
 	data := make(map[string]interface{})
 	data["active"] = active
@@ -1341,6 +1349,24 @@ func (c *Client) UpdateLastViewedAt(channelId string, active bool) (*Result, *Ap
 	}
 }
 
+// ViewChannel performs all the actions related to viewing a channel. This includes marking
+// the channel and the previous one as read, marking the channel as being actively viewed.
+// ChannelId is required but may be blank to indicate no channel is being viewed.
+// PrevChannelId is optional, populate to indicate a channel switch occurred. Optionally
+// provide a non-zero Time, in Unix milliseconds, to manually set the viewing time.
+func (c *Client) ViewChannel(params ChannelView) (bool, *ResponseMetadata) {
+	if r, err := c.DoApiPost(c.GetTeamRoute()+"/channels/view", params.ToJson()); err != nil {
+		return false, &ResponseMetadata{StatusCode: r.StatusCode, Error: err}
+	} else {
+		return c.CheckStatusOK(r),
+			&ResponseMetadata{
+				StatusCode: r.StatusCode,
+				RequestId:  r.Header.Get(HEADER_REQUEST_ID),
+				Etag:       r.Header.Get(HEADER_ETAG_SERVER),
+			}
+	}
+}
+
 func (c *Client) GetChannelStats(id string, etag string) (*Result, *AppError) {
 	if r, err := c.DoApiGet(c.GetChannelRoute(id)+"/stats", "", etag); err != nil {
 		return nil, err
@@ -1718,6 +1744,7 @@ func (c *Client) GetStatusesByIds(userIds []string) (*Result, *AppError) {
 // SetActiveChannel sets the the channel id the user is currently viewing.
 // The channelId key is required but the value can be blank. Returns standard
 // response.
+// SCHEDULED FOR DEPRECATION IN 3.8 - use ViewChannel instead
 func (c *Client) SetActiveChannel(channelId string) (*Result, *AppError) {
 	data := map[string]string{}
 	data["channel_id"] = channelId
diff --git a/webapp/actions/channel_actions.jsx b/webapp/actions/channel_actions.jsx
index ad2f315ee..952c8ada3 100644
--- a/webapp/actions/channel_actions.jsx
+++ b/webapp/actions/channel_actions.jsx
@@ -53,7 +53,7 @@ export function executeCommand(message, args, success, error) {
 
 export function setChannelAsRead(channelIdParam) {
     const channelId = channelIdParam || ChannelStore.getCurrentId();
-    AsyncClient.updateLastViewedAt();
+    AsyncClient.viewChannel();
     ChannelStore.resetCounts(channelId);
     ChannelStore.emitChange();
     if (channelId === ChannelStore.getCurrentId()) {
diff --git a/webapp/actions/global_actions.jsx b/webapp/actions/global_actions.jsx
index 9d135dd26..e1009e9c2 100644
--- a/webapp/actions/global_actions.jsx
+++ b/webapp/actions/global_actions.jsx
@@ -48,7 +48,7 @@ export function emitChannelClickEvent(channel) {
 
         getMyChannelMembersPromise.then(() => {
             AsyncClient.getChannelStats(chan.id, true);
-            AsyncClient.updateLastViewedAt(chan.id);
+            AsyncClient.viewChannel(chan.id, ChannelStore.getCurrentId());
             loadPosts(chan.id);
             trackPage();
         });
diff --git a/webapp/actions/post_actions.jsx b/webapp/actions/post_actions.jsx
index d1e69cda7..71b9e826e 100644
--- a/webapp/actions/post_actions.jsx
+++ b/webapp/actions/post_actions.jsx
@@ -22,7 +22,7 @@ export function handleNewPost(post, msg) {
 
     if (ChannelStore.getCurrentId() === post.channel_id) {
         if (window.isActive) {
-            AsyncClient.updateLastViewedAt(null, false);
+            AsyncClient.viewChannel();
         } else {
             AsyncClient.getChannel(post.channel_id);
         }
diff --git a/webapp/actions/websocket_actions.jsx b/webapp/actions/websocket_actions.jsx
index 6c81a4ac9..f24802003 100644
--- a/webapp/actions/websocket_actions.jsx
+++ b/webapp/actions/websocket_actions.jsx
@@ -205,7 +205,7 @@ function handlePostEditEvent(msg) {
     // Update channel state
     if (ChannelStore.getCurrentId() === msg.broadcast.channel_id) {
         if (window.isActive) {
-            AsyncClient.updateLastViewedAt(null, false);
+            AsyncClient.viewChannel();
         }
     }
 }
diff --git a/webapp/client/client.jsx b/webapp/client/client.jsx
index 3ec36644f..c5743ae7b 100644
--- a/webapp/client/client.jsx
+++ b/webapp/client/client.jsx
@@ -1187,6 +1187,7 @@ export default class Client {
             end(this.handleResponse.bind(this, 'getStatuses', success, error));
     }
 
+    // SCHEDULED FOR DEPRECATION IN 3.8 - use viewChannel instead
     setActiveChannel(id, success, error) {
         request.
             post(`${this.getUsersRoute()}/status/set_active_channel`).
@@ -1366,6 +1367,17 @@ export default class Client {
         this.track('api', 'api_channels_delete');
     }
 
+    viewChannel(channelId, prevChannelId = '', time = 0, success, error) {
+        request.
+            post(`${this.getChannelsRoute()}/view`).
+            set(this.defaultHeaders).
+            type('application/json').
+            accept('application/json').
+            send({channel_id: channelId, prev_channel_id: prevChannelId, time}).
+            end(this.handleResponse.bind(this, 'viewChannel', success, error));
+    }
+
+    // SCHEDULED FOR DEPRECATION IN 3.8 - use viewChannel instead
     updateLastViewedAt(channelId, active, success, error) {
         request.
             post(`${this.getChannelNeededRoute(channelId)}/update_last_viewed_at`).
@@ -1376,6 +1388,7 @@ export default class Client {
             end(this.handleResponse.bind(this, 'updateLastViewedAt', success, error));
     }
 
+    // SCHEDULED FOR DEPRECATION IN 3.8 - use viewChannel instead
     setLastViewedAt(channelId, lastViewedAt, success, error) {
         request.
         post(`${this.getChannelNeededRoute(channelId)}/set_last_viewed_at`).
diff --git a/webapp/components/needs_team.jsx b/webapp/components/needs_team.jsx
index f90297065..0b91814c3 100644
--- a/webapp/components/needs_team.jsx
+++ b/webapp/components/needs_team.jsx
@@ -94,7 +94,7 @@ export default class NeedsTeam extends React.Component {
         // Set up tracking for whether the window is active
         window.isActive = true;
         $(window).on('focus', () => {
-            AsyncClient.updateLastViewedAt();
+            AsyncClient.viewChannel();
             ChannelStore.resetCounts(ChannelStore.getCurrentId());
             ChannelStore.emitChange();
             window.isActive = true;
@@ -103,7 +103,7 @@ export default class NeedsTeam extends React.Component {
         $(window).on('blur', () => {
             window.isActive = false;
             if (UserStore.getCurrentUser()) {
-                AsyncClient.setActiveChannel('');
+                AsyncClient.viewChannel('');
             }
         });
 
diff --git a/webapp/components/post_view/post_view_cache.jsx b/webapp/components/post_view/post_view_cache.jsx
index 3b6123b09..7de11d667 100644
--- a/webapp/components/post_view/post_view_cache.jsx
+++ b/webapp/components/post_view/post_view_cache.jsx
@@ -32,7 +32,7 @@ export default class PostViewCache extends React.Component {
 
     componentWillUnmount() {
         if (UserStore.getCurrentUser()) {
-            AsyncClient.setActiveChannel('');
+            AsyncClient.viewChannel('');
         }
         ChannelStore.removeChangeListener(this.onChannelChange);
     }
diff --git a/webapp/tests/client_channel.test.jsx b/webapp/tests/client_channel.test.jsx
index 08c821f3c..77f9f9653 100644
--- a/webapp/tests/client_channel.test.jsx
+++ b/webapp/tests/client_channel.test.jsx
@@ -211,6 +211,23 @@ describe('Client.Channels', function() {
         });
     });
 
+    it('viewChannel', function(done) {
+        TestHelper.initBasic(() => {
+            var channel = TestHelper.basicChannel();
+            TestHelper.basicClient().viewChannel(
+                channel.id,
+                '',
+                0,
+                function() {
+                    done();
+                },
+                function(err) {
+                    done(new Error(err.message));
+                }
+            );
+        });
+    });
+
     it('updateLastViewedAt', function(done) {
         TestHelper.initBasic(() => {
             var channel = TestHelper.basicChannel();
diff --git a/webapp/utils/async_client.jsx b/webapp/utils/async_client.jsx
index 2d8e76fc2..66f13f04d 100644
--- a/webapp/utils/async_client.jsx
+++ b/webapp/utils/async_client.jsx
@@ -138,33 +138,20 @@ export function getMyChannelMembers() {
     });
 }
 
-export function updateLastViewedAt(id, active) {
-    let channelId;
-    if (id) {
-        channelId = id;
-    } else {
-        channelId = ChannelStore.getCurrentId();
-    }
-
+export function viewChannel(channelId = ChannelStore.getCurrentId(), prevChannelId = '', time = 0) {
     if (channelId == null) {
         return;
     }
 
-    if (isCallInProgress(`updateLastViewed${channelId}`)) {
+    if (isCallInProgress(`viewChannel${channelId}`)) {
         return;
     }
 
-    let isActive;
-    if (active == null) {
-        isActive = true;
-    } else {
-        isActive = active;
-    }
-
-    callTracker[`updateLastViewed${channelId}`] = utils.getTimestamp();
-    Client.updateLastViewedAt(
+    callTracker[`viewChannel${channelId}`] = utils.getTimestamp();
+    Client.viewChannel(
         channelId,
-        isActive,
+        prevChannelId,
+        time,
         () => {
             AppDispatcher.handleServerAction({
                 type: ActionTypes.RECEIVED_PREFERENCE,
@@ -175,59 +162,14 @@ export function updateLastViewedAt(id, active) {
                 }
             });
 
-            callTracker[`updateLastViewed${channelId}`] = 0;
+            callTracker[`viewChannel${channelId}`] = 0;
             ErrorStore.clearLastError();
         },
         (err) => {
-            callTracker[`updateLastViewed${channelId}`] = 0;
+            callTracker[`viewChannel${channelId}`] = 0;
             const count = ErrorStore.getConnectionErrorCount();
             ErrorStore.setConnectionErrorCount(count + 1);
-            dispatchError(err, 'updateLastViewedAt');
-        }
-    );
-}
-
-export function setLastViewedAt(lastViewedAt, id) {
-    let channelId;
-    if (id) {
-        channelId = id;
-    } else {
-        channelId = ChannelStore.getCurrentId();
-    }
-
-    if (channelId == null) {
-        return;
-    }
-
-    if (lastViewedAt == null) {
-        return;
-    }
-
-    if (isCallInProgress(`setLastViewedAt${channelId}${lastViewedAt}`)) {
-        return;
-    }
-
-    callTracker[`setLastViewedAt${channelId}${lastViewedAt}`] = utils.getTimestamp();
-    Client.setLastViewedAt(
-        channelId,
-        lastViewedAt,
-        () => {
-            AppDispatcher.handleServerAction({
-                type: ActionTypes.RECEIVED_PREFERENCE,
-                preference: {
-                    category: 'last',
-                    name: TeamStore.getCurrentId(),
-                    value: channelId
-                }
-            });
-            callTracker[`setLastViewedAt${channelId}${lastViewedAt}`] = 0;
-            ErrorStore.clearLastError();
-        },
-        (err) => {
-            callTracker[`setLastViewedAt${channelId}${lastViewedAt}`] = 0;
-            var count = ErrorStore.getConnectionErrorCount();
-            ErrorStore.setConnectionErrorCount(count + 1);
-            dispatchError(err, 'setLastViewedAt');
+            dispatchError(err, 'viewChannel');
         }
     );
 }
@@ -795,24 +737,6 @@ export function getStatuses() {
     );
 }
 
-export function setActiveChannel(channelId) {
-    if (isCallInProgress(`setActiveChannel${channelId}`)) {
-        return;
-    }
-
-    callTracker[`setActiveChannel${channelId}`] = utils.getTimestamp();
-    Client.setActiveChannel(
-        channelId,
-        () => {
-            callTracker[`setActiveChannel${channelId}`] = 0;
-        },
-        (err) => {
-            callTracker[`setActiveChannel${channelId}`] = 0;
-            dispatchError(err, 'setActiveChannel');
-        }
-    );
-}
-
 export function getMyTeam() {
     if (isCallInProgress('getMyTeam')) {
         return null;