[backend] Rewrite the config parsing system

.idea/dictionaries/project.xml

···
       <w>appview</w>
       <w>atcute</w>
       <w>atproto</w>
+      <w>atprotocol</w>
       <w>bluesky</w>
       <w>bsky</w>
       <w>clippr</w>
···
       <w>llms</w>
       <w>llmstxt</w>
       <w>multiformats</w>
+      <w>nodeinfo</w>
       <w>nsid</w>
       <w>outdir</w>
       <w>rkey</w>

backend/config.example.toml

···
 ## This is a configuration file for Clippr.
 ## Please copy to "config.example.toml" before starting the server,
 ## otherwise it will not start. Modify as necessary.
-## All keys that are listed are expected to be included in the config, even if not explicity declared as required.
 
 ## Where the server is broadcasted to.
 hostname = "localhost"
 port = 9090
-webDomain = "https://localhost"
+
+## Where the server will be deployed to.
+baseUrl = "https://localhost:9090"
 
 ## For most deployments, you will want to keep the log level at "info".
 ## If you are a developer, move it down to "debug" for more information.
···
 logLevel = "info"
 
 ## How the SQLite database is stored.
-## For experimenting, you can store the database in memory with ":memory:"
+## NOTE: Storing the database in-memory does not work as the schema is not properly loaded. Fixme!
 [database]
 ## Paths can be used here.
 name = "file:clippr.db"
···
 ## How the server interacts with the ATproto network.
 [network]
 ## What Jetstream instance to use for receiving content from the network.
+## Non-Bluesky relay: relay2.fire.hose.cam
 firehose = "jetstream1.us-east.bsky.network"
 ## What DID to use for service proxying. This should be the domain that the API is accessible from.
 ## Default: "did:web:localhost%3A9090"
 serviceDid = "did:web:localhost%3A9090"
-## A multibase public key to use for signing in the service proxy DID, formatted as "did:key:[key]". Required.
-## Do not use the default key outside of testing.
+## A multibase public key to use for DID service proxying, formatted as "did:key:[key]".
+## Do not use the default key outside of development.
 didSigningKey = "did:key:zDnaeuuRRQuYp4S76LwosLhHbpU1HJcg6S5oJAUHmdZLVdLM5"

backend/drizzle.config.ts

···
 // @ts-expect-error Read from the TypeScript file instead of assuming that it's JavaScript
 import { Config } from "./src/config.ts";
 
-const config = Config.getInstance();
+const config = Config.getInstance().getConfig();
 let dbname;
 
-dbname = config.get("database.name");
-if (typeof dbname !== "string") {
-	dbname = "file:clippr.db"; // Only way to disable linter error
-}
+dbname = config.database.name;
 
 export default defineConfig({
 	out: "./drizzle",

backend/src/config.ts

···
 import { readFileSync } from "fs";
 import * as toml from "toml";
 
+interface ConfigSchema {
+	hostname: string | "localhost";
+	port: number | 9090;
+	baseUrl: string | "http://localhost:9090";
+	logLevel: string | "debug";
+	database: {
+		name: string | "file:clippr.db";
+	};
+	network: {
+		firehose: string | "jetstream1.us-east.bsky.network";
+		serviceDid: string | "did:web:localhost%3A9090";
+		didSigningKey: string | "did:key:zDnaeuuRRQuYp4S76LwosLhHbpU1HJcg6S5oJAUHmdZLVdLM5";
+	};
+}
+
+class ConfigError extends Error {
+	constructor(message: string) {
+		super(message);
+		this.name = "ConfigError";
+	}
+}
+
 export class Config {
 	private static instance: Config;
-	private readonly configData;
+	private readonly configData: ConfigSchema;
 
 	private constructor() {
 		let tomlString;
 		try {
 			tomlString = readFileSync("config.toml", "utf-8");
 		} catch {
-			throw new Error("Config file not found");
+			throw new ConfigError("Config file not found");
 		}
-		this.configData = toml.parse(tomlString);
+
+		try {
+			this.configData = toml.parse(tomlString);
+		} catch {
+			throw new ConfigError(`Config file is not valid TOML`);
+		}
 	}
 
+	/**
+	 * Gets a singleton instance of the program configuration
+	 * @throws {ConfigError} if the config file cannot be read or parsed
+	 */
 	static getInstance(): Config {
 		if (!Config.instance) {
 			try {
···
 		return Config.instance;
 	}
 
-	get<T>(path: string): T | undefined {
-		const keys = path.split(".");
-		let value = this.configData;
-		for (const key of keys) {
-			if (value == null) return undefined;
-			value = value[key];
-		}
-		return value;
-	}
-
-	getAll() {
+	getConfig(): ConfigSchema {
 		return this.configData;
 	}
 }

backend/src/db/database.ts

···
 import { Config } from "../config.js";
 import Logger from "../logger.js";
 
-const config = Config.getInstance();
-const dbname = config.get("database.name");
+const config = Config.getInstance().getConfig();
+const dbname = config.database.name;
 
 export class Database {
 	private static instance: Database;

backend/src/logger.ts

···
  */
 
 import { createLogger, format, transports } from "winston";
+import { Config } from "./config.js";
 
-// TODO: I can't seem to actually get the config setting for the log level yet.
-const logLevel = "debug";
+const config = Config.getInstance().getConfig();
+const logLevel = config.logLevel;
 
 const Logger = createLogger({
 	level: logLevel,

backend/src/main.ts

···
 	logger.info("Clippr-BE starting...");
 
 	logger.verbose("Reading configuration...");
-	const config = Config.getInstance();
+	const config = Config.getInstance().getConfig();
 
 	logger.verbose("Initializing database...");
 	Database.getInstance();
···
 	readFromFirehose();
 
 	const server: ServerType = serve({
-		port: config.get("port"),
-		hostname: config.get("hostname"),
+		port: config.port,
+		hostname: config.hostname,
 		fetch: app.fetch,
 	});
 
 	logger.info(
-		`XRPC server launched at http://${config.get("hostname")}:${config.get("port")}`,
+		`XRPC server launched at http://${config.hostname}:${config.port}`,
 	);
 
 	process.removeAllListeners("SIGINT");

backend/src/network/jetstream.ts

···
 import { handleClip, handleProfile, handleTag } from "./commit.js";
 import Logger from "../logger.js";
 
-const config = Config.getInstance();
-const hostname = config.get("network.firehose");
+const config = Config.getInstance().getConfig();
+const hostname = config.network.firehose;
 
 const jetstream = new Jetstream({
 	endpoint: `wss://${hostname}/subscribe`,

backend/src/routes/well-known.ts

···
 import { getStats } from "../api/stats.js";
 
 const app = new Hono();
-const config = Config.getInstance();
+const config = Config.getInstance().getConfig();
 
-const serviceDid: string =
-	config.get("network.serviceDid") ||
-	`did:web:${config.get("hostname")}%3A${config.get("port")}/`;
-const signingKey: string | unknown = config.get("network.didSigningKey");
-let webDomain: string =
-	config.get("network.webDomain") ||
-	`http://${config.get("hostname")}:${config.get("port")}`;
+const serviceDid: string = config.network.serviceDid;
+const signingKey: string = config.network.didSigningKey;
+let baseUrl: string = config.baseUrl
 
-if (!webDomain.startsWith("http://") || !webDomain.startsWith("https://")) {
-	webDomain = `http://${webDomain.replace(/^https?:\/\//, "")}`;
+if (!baseUrl.startsWith("http://") || !baseUrl.startsWith("https://")) {
+	baseUrl = `http://${baseUrl.replace(/^https?:\/\//, "")}`;
 }
 
 app.get("/.well-known/nodeinfo", (c) => {
···
 		links: [
 			{
 				rel: "https://nodeinfo.diaspora.software/ns/schema/2.2",
-				href: `${webDomain}/nodeinfo/2.2`,
+				href: `${baseUrl}/nodeinfo/2.2`,
 			},
 			{
 				rel: "https://nodeinfo.diaspora.software/ns/schema/2.1",
-				href: `${webDomain}/nodeinfo/2.1`,
+				href: `${baseUrl}/nodeinfo/2.1`,
 			},
 			{
 				rel: "https://nodeinfo.diaspora.software/ns/schema/2.0",
-				href: `${webDomain}/nodeinfo/2.0`,
+				href: `${baseUrl}/nodeinfo/2.0`,
 			},
 		],
 	});
···
 		);
 	}
 
-	if (typeof signingKey !== "string") {
-		return c.json(
-			{
-				error: "Internal Server Error",
-				message: "Server is not properly configured",
-			},
-			500,
-		);
-	}
-
 	if (!signingKey.replace("did:key:", "").startsWith("z")) {
 		console.log(signingKey);
 		return c.json(
···
 			{
 				id: "#clippr_appview",
 				type: "ClipprAppView",
-				serviceEndpoint: `${webDomain}`,
+				serviceEndpoint: `${baseUrl}`,
 			},
 		],
 	});