--- title: Getting Started --- # Making a Ping-Pong bot One of the first steps to getting started with the Discord API is to write a basic ping-pong bot. We will expand on this to create more diverse commands later, but for now, it is a good starting point. ## Creating a Discord Bot Before you can begin writing your bot, it is necessary to create a bot account on Discord. 1. Visit the [Discord Applications Portal]. 2. Create a New Application. 3. Give the application a name (this will be the bot's initial username). 4. Create the Application.  5. In the application review page, click **Create a Bot User**.  6. Confirm the popup. 7. If this bot will be public, check "Public Bot." **Do not tick any other options!** [Discord Applications Portal]: https://discordapp.com/developers/applications/me ## Adding your bot to a server Bots **cannot** use invite links, they must be explicitly invited through the OAuth2 flow. 1. Open your bot's application on the [Discord Applications Portal]. 2. Retrieve the app's **Client ID**.  3. Create an OAuth2 authorization URL `https://discordapp.com/oauth2/authorize?client_id=<CLIENT ID>&scope=bot` 4. Open the authorization URL in your browser. 5. Select a server. 6. Click on authorize. >[!NOTE] Only servers where you have the `MANAGE_SERVER` permission will be present in this list.  ## Connecting to Discord If you have not already created a project and installed Discord.Net, do that now. (see the [Installing](installing.md) section) ### Async Discord.Net uses .NET's [Task-based Asynchronous Pattern (TAP)] extensively - nearly every operation is asynchronous. It is highly recommended that these operations are awaited in a properly established async context whenever possible. Establishing an async context can be problematic, but not hard. To do so, we will be creating an async main in your console application, and rewriting the static main method to invoke the new async main. [!code-csharp[Async Context](samples/intro/async-context.cs)] As a result of this, your program will now start and immidiately jump into an async context. This will allow us to create a connection to Discord later on without needing to worry about setting up the correct async implementation. >[!TIP] If your application throws any exceptions within an async context, they will be thrown all the way back up to the first non-async method; since our first non-async method is the program's `Main` method, this means that **all** unhandled exceptions will be thrown up there, which will crash your application. Discord.Net will prevent exceptions in event handlers from crashing your program, but any exceptions in your async main **will** cause the application to crash. [Task-based Asynchronous Pattern (TAP)]: https://docs.microsoft.com/en-us/dotnet/articles/csharp/async ### Creating a logging method Before we create and configure a Discord client, we will add a method to handle Discord.Net's log events. To allow agnostic support of as many log providers as possible, we log information through a `Log` event with a proprietary `LogMessage` parameter. See the [API Documentation] for this event. If you are using your own logging framework, this is where you would invoke it. For the sake of simplicity, we will only be logging to the Console. [!code-csharp[Async Context](samples/intro/logging.cs)] [API Documentation]: xref:Discord.Rest.BaseDiscordClient#Discord_Rest_BaseDiscordClient_Log ### Creating a Discord Client Finally, we can create a connection to Discord. Since we are writing a bot, we will be using a [DiscordSocketClient] along with socket entities. See the [terminology](terminology.md) if you're unsure of the differences. To do so, create an instance of [DiscordSocketClient] in your async main, passing in a configuration object only if necessary. For most users, the default will work fine. Before connecting, we should hook the client's `Log` event to the log handler that was just created. Events in Discord.Net work similarly to other events in C#, so hook this event the way that you typically would. Next, you will need to "login to Discord" with the `LoginAsync` method. You may create a variable to hold your bot's token (this can be found on your bot's application page on the [Discord Applications Portal]).  >[!IMPORTANT] Your bot's token can be used to gain total access to your bot, so **do __NOT__ share this token with anyone else!** It may behoove you to store this token in an external file if you plan on distributing the source code for your bot. We may now invoke the client's `StartAsync` method, which will start connection/reconnection logic. It is important to note that **this method returns as soon as connection logic has been started!** Any methods that rely on the client's state should go in an event handler. Finally, we will want to block the async main method from returning until after the application is exited. To do this, we can await an infinite delay or any other blocking method, such as reading from the console. The following lines can now be added: [!code-csharp[Create client](samples/intro/client.cs)] At this point, feel free to start your program and see your bot come online in Discord. >[!TIP] Encountering a `PlatformNotSupportedException` when starting your bot? This means that you are targeting a platform where .NET's default WebSocket client is not supported. Refer to the [installation guide] for how to fix this. [DiscordSocketClient]: xref:Discord.WebSocket.DiscordSocketClient [installation guide]: installing.md#installing-on-net-standard-11 ### Handling a 'ping' >[!WARNING] Please note that this is *not* a proper way to create a command. Use the `CommandService` provided by the library instead, as explained in the [Command Guide] section. Now that we have learned how to open a connection to Discord, we can begin handling messages that users are sending. To start out, our bot will listen for any message where the content is equal to `!ping` and respond back with "Pong!". Since we want to listen for new messages, the event to hook into is [MessageReceived]. In your program, add a method that matches the signature of the `MessageReceived` event - it must be a method (`Func`) that returns the type `Task` and takes a single parameter, a [SocketMessage]. Also, since we will be sending data to Discord in this method, we will flag it as `async`. In this method, we will add an `if` block to determine if the message content fits the rules of our scenario - recall that it must be equal to `!ping`. Inside the branch of this condition, we will want to send a message back to the channel from which the message comes from - "Pong!". To find the channel, look for the `Channel` property on the message parameter. Next, we will want to send a message to this channel. Since the channel object is of type [SocketMessageChannel], we can invoke the `SendMessageAsync` instance method. For the message content, send back a string containing "Pong!". You should have now added the following lines: [!code-csharp[Message](samples/intro/message.cs)] Now your first bot is complete. You may continue to add on to this if you desire, but for any bots that will be carrying out multiple commands, it is strongly recommended to use the command framework as shown below. For your reference, you may view the [completed program]. [MessageReceived]: xref:Discord.WebSocket.DiscordSocketClient#Discord_WebSocket_DiscordSocketClient_MessageReceived [SocketMessage]: xref:Discord.WebSocket.SocketMessage [SocketMessageChannel]: xref:Discord.WebSocket.ISocketMessageChannel [completed program]: samples/intro/complete.cs [Command Guide]: ../commands/commands.md # Building a bot with commands This section will show you how to write a program that is ready for [Commands](../commands/commands.md). Note that we will not be explaining _how_ to write Commands or Services, it will only be covering the general structure. For reference, view an [annotated example] of this structure. [annotated example]: samples/intro/structure.cs It is important to know that the recommended design pattern of bots should be to separate the program (initialization and command handler), the modules (handle commands), and the services (persistent storage, pure functions, data manipulation). **todo:** diagram of bot structure