feat: Add strategy to post to Discord (#43)

Author: nzakas

README.md

@@ -26,6 +26,7 @@ The API is split into two parts:
     - `MastodonStrategy`
     - `TwitterStrategy`
     - `LinkedInStrategy`
+    - `DiscordStrategy`
 
 Each strategy requires its own parameters that are specific to the service. If you only want to post to a particular service, you can just directly use the strategy for that service.
 
@@ -35,6 +36,8 @@ import {
 	TwitterStrategy,
 	MastodonStrategy,
 	BlueskyStrategy,
+	LinkedInStrategy,
+	DiscordStrategy,
 } from "@humanwhocodes/crosspost";
 
 // Note: Use an app password, not your login password!
@@ -63,9 +66,15 @@ const linkedin = new LinkedInStrategy({
 	accessToken: "your-access-token",
 });
 
-// create a client that will post to all three
+// Note: Bot token and channel ID required
+const discord = new DiscordStrategy({
+	botToken: "your-bot-token",
+	channelId: "your-channel-id",
+});
+
+// create a client that will post to all services
 const client = new Client({
-	strategies: [bluesky, mastodon, twitter, linkedin],
+	strategies: [bluesky, mastodon, twitter, linkedin, discord],
 });
 
 // post to all three
@@ -82,6 +91,7 @@ Usage: crosspost [options] ["Message to post."]
 --mastodon, -m  Post to Mastodon.
 --bluesky, -b   Post to Bluesky.
 --linkedin, -l  Post to LinkedIn.
+--discord, -d   Post to Discord.
 --file, -f      The file to read the message from.
 --help, -h      Show this message.
 ```
@@ -124,6 +134,9 @@ Each strategy requires a set of environment variables in order to execute:
     -   `BLUESKY_PASSWORD`
 -   LinkedIn
     -   `LINKEDIN_ACCESS_TOKEN`
+-   Discord
+    -   `DISCORD_BOT_TOKEN`
+    -   `DISCORD_CHANNEL_ID`
 
 Tip: You can also load environment variables from a `.env` file in the current working directory by setting the environment variable `CROSSPOST_DOTENV` to `1`.
 
@@ -187,6 +200,38 @@ To enable posting to LinkedIn, follow these steps:
 
 **Important:** Tokens automatically expire after two months.
 
+### Discord
+
+To enable posting to Discord, you'll need to create a bot and get its token:
+
+1. Go to the [Discord Developer Portal](https://discord.com/developers/applications).
+2. Click "New Application".
+3. Give your application a name and click "Create".
+4. Click "Installation" in the left sidebar.
+5. Under "Install Link" select "None".
+6. Click "Save Changes".
+7. Click on "Bot" in the left sidebar.
+8. Uncheck "Public Bot" to ensure no one else can add this bot.
+9. Under "Text Permissions" check "Send Messages".
+10. Click "Save Changes".
+11. Click "Reset Token" and copy the bot token that appears.
+
+To add the bot to your server:
+
+1. In the Developer Portal, click on "OAuth2" in the left sidebar.
+2. Under "OAuth2 URL Generator", check "bot".
+3. Under "Bot Permissions", check "Send Messages" under "Text Permissions".
+4. Copy the generated URL and open it in your browser.
+5. Select your server and authorize the bot.
+
+To get your channel ID:
+
+1. Enable Developer Mode in Discord (User Settings > Advanced > Developer Mode).
+2. Right-click the channel you want to post to.
+3. Click "Copy Channel ID".
+
+**Note:** By default your application will only be able to send messages to public channels. To send messages to private channels, you'll have to give your application the necessary permissions.
+
 ## License
 
 Copyright 2024-2025 Nicholas C. Zakas

release-please-config.json

@@ -9,7 +9,8 @@
           "type": "json",
           "path": "jsr.json",
           "jsonpath": "$.version"
-        }
+        },
+        "src/strategies/discord.js"
       ]
     }
   }

src/bin.js

@@ -16,6 +16,7 @@ import {
 	MastodonStrategy,
 	BlueskyStrategy,
 	LinkedInStrategy,
+	DiscordStrategy,
 } from "./index.js";
 import fs from "node:fs";
 
@@ -51,6 +52,7 @@ const options = {
 	mastodon: { type: booleanType, short: "m" },
 	bluesky: { type: booleanType, short: "b" },
 	linkedin: { type: booleanType, short: "l" },
+	discord: { type: booleanType, short: "d" },
 	file: { type: stringType },
 	help: { type: booleanType, short: "h" },
 };
@@ -63,13 +65,18 @@ const { values: flags, positionals } = parseArgs({
 if (
 	flags.help ||
 	(positionals.length === 0 && !flags.file) ||
-	(!flags.twitter && !flags.mastodon && !flags.bluesky && !flags.linkedin)
+	(!flags.twitter &&
+		!flags.mastodon &&
+		!flags.bluesky &&
+		!flags.linkedin &&
+		!flags.discord)
 ) {
 	console.log('Usage: crosspost [options] ["Message to post."]');
 	console.log("--twitter, -t	Post to Twitter.");
 	console.log("--mastodon, -m	Post to Mastodon.");
 	console.log("--bluesky, -b	Post to Bluesky.");
 	console.log("--linkedin, -l	Post to LinkedIn.");
+	console.log("--discord, -d	Post to Discord.");
 	console.log("--file		The file to read the message from.");
 	console.log("--help, -h	Show this message.");
 	process.exit(1);
@@ -98,7 +105,7 @@ const env = new Env();
 // Determine which strategies to use
 //-----------------------------------------------------------------------------
 
-/** @type {Array<TwitterStrategy|MastodonStrategy|BlueskyStrategy|LinkedInStrategy>} */
+/** @type {Array<TwitterStrategy|MastodonStrategy|BlueskyStrategy|LinkedInStrategy|DiscordStrategy>} */
 const strategies = [];
 
 if (flags.twitter) {
@@ -139,6 +146,15 @@ if (flags.linkedin) {
 	);
 }
 
+if (flags.discord) {
+	strategies.push(
+		new DiscordStrategy({
+			botToken: env.require("DISCORD_BOT_TOKEN"),
+			channelId: env.require("DISCORD_CHANNEL_ID"),
+		}),
+	);
+}
+
 //-----------------------------------------------------------------------------
 // Main
 //-----------------------------------------------------------------------------

src/index.js

@@ -7,4 +7,5 @@ export * from "./strategies/bluesky.js";
 export * from "./strategies/mastodon.js";
 export * from "./strategies/twitter.js";
 export * from "./strategies/linkedin.js";
+export * from "./strategies/discord.js";
 export * from "./client.js";

src/strategies/discord.js

@@ -0,0 +1,114 @@
+/**
+ * @fileoverview Discord strategy for posting messages.
+ * @author Nicholas C. Zakas
+ */
+
+/* global fetch */
+
+//-----------------------------------------------------------------------------
+// Type Definitions
+//-----------------------------------------------------------------------------
+
+/**
+ * @typedef {Object} DiscordOptions
+ * @property {string} botToken The Discord bot token.
+ * @property {string} channelId The Discord channel ID to post to.
+ */
+
+/**
+ * @typedef {Object} DiscordMessageResponse
+ * @property {string} id The ID of the created message.
+ * @property {string} channel_id The ID of the channel the message was posted to.
+ * @property {string} content The content of the message.
+ */
+
+/**
+ * @typedef {Object} DiscordErrorResponse
+ * @property {number} code The error code.
+ * @property {string} message The error message.
+ */
+
+//-----------------------------------------------------------------------------
+// Constants
+//-----------------------------------------------------------------------------
+
+const API_BASE = "https://discord.com/api/v10";
+
+//-----------------------------------------------------------------------------
+// Exports
+//-----------------------------------------------------------------------------
+
+/**
+ * A strategy for posting messages to Discord.
+ */
+export class DiscordStrategy {
+	/**
+	 * The name of the strategy.
+	 * @type {string}
+	 * @readonly
+	 */
+	name = "discord";
+
+	/**
+	 * Options for this instance.
+	 * @type {DiscordOptions}
+	 */
+	#options;
+
+	/**
+	 * Creates a new instance.
+	 * @param {DiscordOptions} options Options for the instance.
+	 * @throws {Error} When options are missing.
+	 */
+	constructor(options) {
+		const { botToken, channelId } = options;
+
+		if (!botToken) {
+			throw new TypeError("Missing bot token.");
+		}
+
+		if (!channelId) {
+			throw new TypeError("Missing channel ID.");
+		}
+
+		this.#options = options;
+	}
+
+	/**
+	 * Posts a message to Discord.
+	 * @param {string} message The message to post.
+	 * @returns {Promise<DiscordMessageResponse>} A promise that resolves with the message data.
+	 * @throws {Error} When the message fails to post.
+	 */
+	async post(message) {
+		if (!message) {
+			throw new TypeError("Missing message to post.");
+		}
+
+		const url = `${API_BASE}/channels/${this.#options.channelId}/messages`;
+		const response = await fetch(url, {
+			method: "POST",
+			headers: {
+				Authorization: `Bot ${this.#options.botToken}`,
+				"Content-Type": "application/json",
+				"User-Agent":
+					"Crosspost CLI (https://github.com/humanwhocodes/crosspost, v0.5.0)", // x-release-please-version
+			},
+			body: JSON.stringify({
+				content: message,
+			}),
+		});
+
+		if (!response.ok) {
+			const errorResponse = /** @type {DiscordErrorResponse} */ (
+				await response.json()
+			);
+
+			throw new Error(
+				`${response.status} Failed to post message: ${response.statusText}\n${errorResponse.message} (code: ${errorResponse.code})`,
+			);
+		}
+
+		return /** @type {Promise<DiscordMessageResponse>} */ (response.json());
+	}
+}