post a system message after a channel is converted from public to private (#8501)

api4/channel.go

@@ -118,6 +118,7 @@ func updateChannel(c *Context, w http.ResponseWriter, r *http.Request) {
 	oldChannel.Purpose = channel.Purpose
 
 	oldChannelDisplayName := oldChannel.DisplayName
+	oldChannelType := oldChannel.Type
 
 	if len(channel.DisplayName) > 0 {
 		oldChannel.DisplayName = channel.DisplayName
@@ -140,6 +141,13 @@ func updateChannel(c *Context, w http.ResponseWriter, r *http.Request) {
 				l4g.Error(err.Error())
 			}
 		}
+
+		if oldChannelType == model.CHANNEL_OPEN && channel.Type == model.CHANNEL_PRIVATE {
+			if err := c.App.PostConvertChannelToPrivate(c.Session.UserId, channel); err != nil {
+				l4g.Error(err.Error())
+			}
+		}
+
 		c.LogAudit("name=" + channel.Name)
 		w.Write([]byte(oldChannel.ToJson()))
 	}

app/channel.go

@@ -805,6 +805,34 @@ func (a *App) PostUpdateChannelDisplayNameMessage(userId string, channel *model.
 	return nil
 }
 
+func (a *App) PostConvertChannelToPrivate(userId string, channel *model.Channel) *model.AppError {
+	uc := a.Srv.Store.User().Get(userId)
+
+	if uresult := <-uc; uresult.Err != nil {
+		return model.NewAppError("PostConvertChannelToPrivate", "api.channel.post_convert_channel_to_private.retrieve_user.error", nil, uresult.Err.Error(), http.StatusBadRequest)
+	} else {
+		user := uresult.Data.(*model.User)
+
+		message := fmt.Sprintf(utils.T("api.channel.post_convert_channel_to_private.updated_from"), user.Username)
+
+		post := &model.Post{
+			ChannelId: channel.Id,
+			Message:   message,
+			Type:      model.POST_CONVERT_CHANNEL,
+			UserId:    userId,
+			Props: model.StringInterface{
+				"username": user.Username,
+			},
+		}
+
+		if _, err := a.CreatePost(post, channel, false); err != nil {
+			return model.NewAppError("PostConvertChannelToPrivate", "api.channel.post_convert_channel_to_private.create_post.error", nil, err.Error(), http.StatusInternalServerError)
+		}
+	}
+
+	return nil
+}
+
 func (a *App) GetChannel(channelId string) (*model.Channel, *model.AppError) {
 	if result := <-a.Srv.Store.Channel().Get(channelId, true); result.Err != nil && result.Err.Id == "store.sql_channel.get.existing.app_error" {
 		result.Err.StatusCode = http.StatusNotFound

i18n/en.json

@@ -331,6 +331,18 @@
     "id": "api.channel.leave.left",
     "translation": "%v left the channel."
   },
+  {
+    "id": "api.channel.post_convert_channel_to_private.create_post.error",
+    "translation": "Failed to post channel conversion to private message"
+  },
+  {
+    "id": "api.channel.post_convert_channel_to_private.retrieve_user.error",
+    "translation": "Failed to retrieve user while converting the channel from public to private"
+  },
+  {
+    "id": "api.channel.post_convert_channel_to_private.updated_from",
+    "translation": "%s converted the channel from public to private"
+  },
   {
     "id": "api.channel.post_update_channel_displayname_message_and_forget.create_post.error",
     "translation": "Failed to post displayname update message"

model/post.go

@@ -33,6 +33,7 @@ const (
 	POST_REMOVE_FROM_TEAM       = "system_remove_from_team"
 	POST_HEADER_CHANGE          = "system_header_change"
 	POST_DISPLAYNAME_CHANGE     = "system_displayname_change"
+	POST_CONVERT_CHANNEL        = "system_convert_channel"
 	POST_PURPOSE_CHANGE         = "system_purpose_change"
 	POST_CHANNEL_DELETED        = "system_channel_deleted"
 	POST_EPHEMERAL              = "system_ephemeral"
@@ -207,6 +208,7 @@ func (o *Post) IsValid(maxPostSize int) *AppError {
 		POST_HEADER_CHANGE,
 		POST_PURPOSE_CHANGE,
 		POST_DISPLAYNAME_CHANGE,
+		POST_CONVERT_CHANNEL,
 		POST_CHANNEL_DELETED,
 		POST_CHANGE_CHANNEL_PRIVACY:
 	default: