重新连接后无法更新以前的消息

Question

我创建了一个带有命令的机器人，允许用户为他们的频道配置某种 'feed'。

此提要应该发送一条消息，保存公会、频道和消息 ID。并在独立的更新周期中，尝试用新信息更新消息。

只要在同一个会话中，这一切都很好。

假设机器人由于不和谐中断而失去连接，并在 x 时间后重新连接，机器人似乎不再能够找到，因此不再更新消息。

特别是好像无法通过id取回消息
var message = await channel.GetMessageAsync(playtimeFeed.MessageId) as SocketUserMessage;

值得注意的是，我使用了 _settings，它以 json 格式保存，并在 bot 重启时再次加载。

我也确认了该消息仍然存在于该频道的服务器中，具有相同的消息ID。并且该机器人有权查看该频道的消息历史记录。

所以我的问题是，为什么 GetMessageAsync 在重新连接后无法检索以前发布的消息？

最初调用的命令

public async Task BindPlaytimeFeedAsync(ICommandContext context)
{
    var builder = await _scumService.GetTop25PlaytimeByDate(new DateTime(), DateTime.Now);

    var message = await context.Channel.SendMessageAsync(null, false, builder.Build());
    _settings.PlaytimeFeed = new MessageInfo()
    {
        GuildId = context.Guild.Id,
        ChannelId = context.Channel.Id,
        MessageId = message.Id,
    };
    var ptFeedMessage = await context.Channel.SendMessageAsync("Playtime feed is now bound to this channel (this message self-destructs in 5 seconds)");
    await Task.Delay(5000);
    await ptFeedMessage.DeleteAsync();
}

提要的刷新间隔是使用计时器与机器人本身一起定义的，如下所示。

...
_client = new DiscordSocketClient(
    new DiscordSocketConfig
    {
        LogLevel = LogSeverity.Verbose,
        AlwaysDownloadUsers = true, // Start the cache off with updated information.
        MessageCacheSize = 1000
    }
);
_service = ConfigureServices();

_feedInterval = new Timer(async (e) =>
{
    Console.WriteLine("doing feed stuff");
    await HandleFeedsAsync();
}, null, 15000, 300000);
CmdHandler = new CommandHandler(_service, state);

...

private async Task HandleFeedsAsync()
{
    var botSettings = _service.GetService<ISettings>() as BotSettings;

    await HandleKdFeedAsync(botSettings.KdFeed);
    await HandlePlaytimeFeedAsync(botSettings.PlaytimeFeed);
    await HandleWeeklyPlaytimeFeed(botSettings.WeeklyPlaytimeFeed);
    await HandleAdminFeed(botSettings);
}

最终使用以下代码段覆盖消息。

private async Task HandlePlaytimeFeedAsync(MessageInfo playtimeFeed)
{
    if (playtimeFeed == null)
        return;

    var scumService = _service.GetService<ScumService>();
    var guild = _client.GetGuild(playtimeFeed.GuildId);
    var channel = guild.GetTextChannel(playtimeFeed.ChannelId);
    var message = await channel.GetMessageAsync(playtimeFeed.MessageId) as SocketUserMessage;
    if (message == null)
        return;
    var builder = await scumService.GetTop25PlaytimeByDate(new DateTime(), DateTime.Now);

    await message.ModifyAsync(prop =>
    {
        prop.Embed = builder.Build();
    });
}

Answer 1

var message = await channel.GetMessageAsync(playtimeFeed.MessageId) as SocketUserMessage;

GetMessageAsync 方法尝试从缓存中检索消息作为 SocketUserMessage，但是如果在缓存中找不到该消息，则会执行休息请求，这将 return RestUserMessge。通过对 GetMessageAsync 的结果执行软转换，您可以获得 null if/when a RestUserMessage 是 returned。

当您处理的消息可能是 Socket 实体或 Rest 实体时，只需使用接口与之交互 -- IUserMessage。

重新连接后无法更新以前的消息

Unable to update previous messages after reconnection

c#

discord.net