static void Main(string[] args)
{
using var host = Host.CreateDefaultBuilder(args)
.UseConfigurationWithEnvironment()
.ConfigureApp((app, context) =>
{
app.Services.AddSingleton<ITelegramBotClient>(_ =>
new TelegramBotClient(context.Configuration["BotToken"]));
app.Services.AddTransient<IUpdateConsumer, Client>();
app.UseHandlers();
app.UseStaticCommands();
})
.Build()
.RunAsync();
Console.ReadLine();
}Command is a class that implements ICommand. They are state-machines that can receive and send messages to telegram user using IClient. Commands are user-scoped which means that injected services save their state between user's inputs.
BF keeps an instance of each command to call Suitable without creating new intance, so you cannot use non-singleton injected services in your Suitable methods. We plan to migrate this to static interface methods once .NET 6 is rolled out.
When a message from user comes in bf it will:
- Scan through all commands with
SuitableFirst; - Search for already created command;
- Scan through all commands with
SuitableLast; - Execute command or return incoming message as result of awaited
GetUpdate.
Most commands you will write will implement IStaticCommand interface. They will be executed based on SuitableFirst/SuitableLast response.
public class EchoCommand : IStaticCommand
{
// It's last to prevent re-creation of a same command.
public bool SuitableLast(Update context) => true;
public async Task Execute(IClient client)
{
// gets last text message. if none are available it will wait untill one arrives.
var message = await client.GetTextMessage();
// sending response back to user. user id is optional because command are user-scoped and bf already knows to whom he is supposed to respond.
await client.SendTextMessage($"Hello, here your last message {message.Text}, type something again");
message = await client.GetTextMessage();
await client.SendTextMessage($"And this is your new message {message.Text}, and now type only message with hello");
await client.SendTextMessage("Well done!");
}
} All commands can be injected with services like this:
public class EchoCommand : IStaticCommand
{
private readonly ILogger logger;
public EchoCommand(ILogger logger)
{
this.logger = logger;
}
public async Task Execute(IClient client)
{
// do your logger.Information("It works")
}
} // todo
// todo
// todo
// todo