From 6fdeee126991a7579d9a0225df0bc84a22e8f33a Mon Sep 17 00:00:00 2001
From: Nikita Karamov <me@kytta.dev>
Date: Sat, 2 Sep 2023 17:53:16 +0200
Subject: [PATCH] Better API code structure

---
 src/components/instance-select.astro |   2 +-
 src/lib/instance.ts                  |  60 +++++++++++
 src/lib/nodeinfo.ts                  |  60 +++++++++++
 src/lib/project.ts                   |  64 ++++++++++++
 src/lib/response.ts                  |  30 ++++++
 src/{scripts/util.ts => lib/url.ts}  |   0
 src/pages/api/detect/[domain].ts     | 146 +++++----------------------
 src/pages/api/instances.ts           |  72 ++-----------
 src/pages/api/share.ts               |  26 +++--
 src/scripts/constants.ts             |  28 -----
 src/stores/saved-instances.ts        |   2 +-
 tsconfig.json                        |   2 +-
 12 files changed, 265 insertions(+), 227 deletions(-)
 create mode 100644 src/lib/instance.ts
 create mode 100644 src/lib/nodeinfo.ts
 create mode 100644 src/lib/project.ts
 create mode 100644 src/lib/response.ts
 rename src/{scripts/util.ts => lib/url.ts} (100%)
 delete mode 100644 src/scripts/constants.ts

diff --git a/src/components/instance-select.astro b/src/components/instance-select.astro
index 1fb7d81..264763e 100644
--- a/src/components/instance-select.astro
+++ b/src/components/instance-select.astro
@@ -87,7 +87,7 @@ const { prefilledInstance } = Astro.props;
 </style>
 
 <script>
-	import { getUrlDomain, normalizeURL } from "@scripts/util";
+	import { getUrlDomain, normalizeURL } from "@lib/url";
 	import { $popularInstances } from "@stores/popular-instances";
 	import { $savedInstances, save } from "@stores/saved-instances";
 
diff --git a/src/lib/instance.ts b/src/lib/instance.ts
new file mode 100644
index 0000000..0430574
--- /dev/null
+++ b/src/lib/instance.ts
@@ -0,0 +1,60 @@
+/*!
+ * This file is part of Share₂Fedi
+ * https://github.com/kytta/share2fedi
+ *
+ * SPDX-FileCopyrightText: © 2023 Nikita Karamov <me@kytta.dev>
+ * SPDX-License-Identifier: AGPL-3.0-only
+ */
+
+import { supportedProjects } from "./project";
+
+interface Instance {
+	domain: string;
+	score: number;
+	active_users_monthly: number;
+	total_users: number;
+}
+
+const getInstancesForProject = async (
+	project: keyof typeof supportedProjects,
+): Promise<Instance[]> => {
+	let instances: Instance[];
+	try {
+		const response = await fetch("https://api.fediverse.observer/", {
+			headers: {
+				Accept: "*/*",
+				"Accept-Language": "en;q=1.0",
+				"Content-Type": "application/json",
+			},
+			referrer: "https://api.fediverse.observer/",
+			body: JSON.stringify({
+				query: `{nodes(status:"UP",softwarename:"${project}"){domain score active_users_monthly total_users}}`,
+			}),
+			method: "POST",
+		});
+		const json = await response.json();
+		instances = json.data.nodes;
+	} catch (error) {
+		console.error(`Could not fetch instances for "${project}"`, error);
+		return [];
+	}
+
+	return instances.filter(
+		(instance) =>
+			instance.score > 90 &&
+			// sanity check for some spammy-looking instances
+			instance.total_users >= instance.active_users_monthly,
+	);
+};
+
+export const getPopularInstanceDomains = async (): Promise<string[]> => {
+	const instancesPerProject = await Promise.all(
+		Object.keys(supportedProjects).map((project) =>
+			getInstancesForProject(project),
+		),
+	);
+	const instances = instancesPerProject.flat();
+	instances.sort((a, b) => b.active_users_monthly - a.active_users_monthly);
+
+	return instances.slice(0, 200).map((instance) => instance.domain);
+};
diff --git a/src/lib/nodeinfo.ts b/src/lib/nodeinfo.ts
new file mode 100644
index 0000000..6ce3143
--- /dev/null
+++ b/src/lib/nodeinfo.ts
@@ -0,0 +1,60 @@
+/*!
+ * This file is part of Share₂Fedi
+ * https://github.com/kytta/share2fedi
+ *
+ * SPDX-FileCopyrightText: © 2023 Nikita Karamov <me@kytta.dev>
+ * SPDX-License-Identifier: AGPL-3.0-only
+ */
+
+import { normalizeURL } from "@lib/url";
+
+interface NodeInfoList {
+	links: {
+		rel: string;
+		href: string;
+	}[];
+}
+
+interface NodeInfo {
+	software: {
+		name: string;
+		version: string;
+		[key: string]: unknown;
+	};
+	[key: string]: unknown;
+}
+
+export const getSoftwareName = async (
+	domain: string,
+): Promise<string | undefined> => {
+	const nodeInfoListUrl = new URL(
+		"/.well-known/nodeinfo",
+		normalizeURL(domain),
+	);
+
+	let nodeInfoList: NodeInfoList;
+	try {
+		const nodeInfoListResponse = await fetch(nodeInfoListUrl);
+		nodeInfoList = await nodeInfoListResponse.json();
+	} catch (error) {
+		console.error("Could not fetch '.well-known/nodeinfo':", error);
+		return undefined;
+	}
+
+	for (const link of nodeInfoList.links) {
+		if (
+			/^http:\/\/nodeinfo\.diaspora\.software\/ns\/schema\/(1\.0|1\.1|2\.0|2\.1)/.test(
+				link.rel,
+			)
+		) {
+			const nodeInfoResponse = await fetch(link.href);
+			const nodeInfo = (await nodeInfoResponse.json()) as NodeInfo;
+
+			return nodeInfo.software.name;
+		}
+	}
+
+	// not found
+	console.warn("No NodeInfo found for domain:", domain);
+	return undefined;
+};
diff --git a/src/lib/project.ts b/src/lib/project.ts
new file mode 100644
index 0000000..350fc16
--- /dev/null
+++ b/src/lib/project.ts
@@ -0,0 +1,64 @@
+/*!
+ * This file is part of Share₂Fedi
+ * https://github.com/kytta/share2fedi
+ *
+ * SPDX-FileCopyrightText: © 2023 Nikita Karamov <me@kytta.dev>
+ * SPDX-License-Identifier: AGPL-3.0-only
+ */
+
+export interface ProjectPublishConfig {
+	endpoint: string;
+	params: {
+		text: string;
+	};
+}
+
+const mastodonConfig: ProjectPublishConfig = {
+	endpoint: "share",
+	params: {
+		text: "text",
+	},
+};
+
+const misskeyConfig: ProjectPublishConfig = {
+	endpoint: "share",
+	params: {
+		text: "text",
+	},
+};
+
+/**
+ * Mapping of the supported fediverse projects.
+ *
+ * The keys of this mapping can be used as keys for the fediverse.observer API,
+ * icon names, etc.
+ */
+export const supportedProjects: Record<string, ProjectPublishConfig> = {
+	calckey: misskeyConfig,
+	fedibird: mastodonConfig,
+	firefish: misskeyConfig,
+	foundkey: misskeyConfig,
+	friendica: {
+		endpoint: "compose",
+		params: {
+			text: "body",
+		},
+	},
+	glitchcafe: mastodonConfig,
+	gnusocial: {
+		endpoint: "notice/new",
+		params: {
+			text: "status_textarea",
+		},
+	},
+	hometown: mastodonConfig,
+	hubzilla: {
+		endpoint: "rpost",
+		params: {
+			text: "body",
+		},
+	},
+	mastodon: mastodonConfig,
+	meisskey: misskeyConfig,
+	misskey: misskeyConfig,
+};
diff --git a/src/lib/response.ts b/src/lib/response.ts
new file mode 100644
index 0000000..9a52ece
--- /dev/null
+++ b/src/lib/response.ts
@@ -0,0 +1,30 @@
+/*!
+ * This file is part of Share₂Fedi
+ * https://github.com/kytta/share2fedi
+ *
+ * SPDX-FileCopyrightText: © 2023 Nikita Karamov <me@kytta.dev>
+ * SPDX-License-Identifier: AGPL-3.0-only
+ */
+
+export const json = (
+	body: unknown,
+	status: number = 200,
+	headers: Record<string, string> = {},
+) => {
+	return new Response(JSON.stringify(body), {
+		headers: {
+			"Content-Type": "application/json",
+			...headers,
+		},
+		status,
+	});
+};
+
+export const error = (message: string, status: number = 400) => {
+	return json(
+		{
+			error: message,
+		},
+		status,
+	);
+};
diff --git a/src/scripts/util.ts b/src/lib/url.ts
similarity index 100%
rename from src/scripts/util.ts
rename to src/lib/url.ts
diff --git a/src/pages/api/detect/[domain].ts b/src/pages/api/detect/[domain].ts
index b451c17..27fc349 100644
--- a/src/pages/api/detect/[domain].ts
+++ b/src/pages/api/detect/[domain].ts
@@ -6,130 +6,38 @@
  * SPDX-License-Identifier: AGPL-3.0-only
  */
 
+import { getSoftwareName } from "@lib/nodeinfo";
+import { ProjectPublishConfig, supportedProjects } from "@lib/project";
+import { error, json } from "@lib/response";
 import type { APIRoute } from "astro";
-import { FediverseProject } from "@scripts/constants";
-import { normalizeURL } from "@scripts/util";
 
-interface FediverseProjectData {
-	publishEndpoint: string;
-	params: {
-		text: string;
-	};
-}
-
-const mastodonSettings = {
-	publishEndpoint: "share",
-	params: {
-		text: "text",
-	},
-};
-
-const misskeySettings = {
-	publishEndpoint: "share",
-	params: {
-		text: "text",
-	},
-};
-
-const PROJECTS: Map<FediverseProject, FediverseProjectData> = new Map()
-	.set(FediverseProject.Mastodon, mastodonSettings)
-	.set(FediverseProject.Fedibird, mastodonSettings)
-	.set(FediverseProject.GlitchCafe, mastodonSettings)
-	.set(FediverseProject.Hometown, mastodonSettings)
-	.set(FediverseProject.Misskey, misskeySettings)
-	.set(FediverseProject.Calckey, misskeySettings)
-	.set(FediverseProject.Firefish, misskeySettings)
-	.set(FediverseProject.FoundKey, misskeySettings)
-	.set(FediverseProject.Meisskey, misskeySettings)
-	.set(FediverseProject.GNUSocial, {
-		publishEndpoint: "/notice/new",
-		params: {
-			text: "status_textarea",
-		},
-	})
-	.set(FediverseProject.Friendica, {
-		publishEndpoint: "compose",
-		params: {
-			text: "body",
-		},
-	})
-	.set(FediverseProject.Hubzilla, {
-		publishEndpoint: "rpost",
-		params: {
-			text: "body",
-		},
-	});
-
-interface NodeInfoList {
-	links: {
-		rel: string;
-		href: string;
-	}[];
-}
-
-interface NodeInfo {
-	[key: string]: unknown;
-	software: {
-		[key: string]: unknown;
-		name: string;
-	};
-}
-
-type NonEmptyArray<T> = [T, ...T[]];
-function isNotEmpty<T>(array: T[]): array is NonEmptyArray<T> {
-	return array.length > 0;
-}
-
-const checkNodeInfo = async (domain: string): Promise<FediverseProject> => {
-	const nodeInfoListUrl = new URL(
-		"/.well-known/nodeinfo",
-		normalizeURL(domain),
-	);
-	const nodeInfoListResponse = await fetch(nodeInfoListUrl);
-	const nodeInfoList = (await nodeInfoListResponse.json()) as NodeInfoList;
-
-	if (isNotEmpty(nodeInfoList.links)) {
-		const nodeInfoUrl = nodeInfoList.links[0].href;
-		const nodeInfoResponse = await fetch(nodeInfoUrl);
-		const nodeInfo = (await nodeInfoResponse.json()) as NodeInfo;
-
-		return nodeInfo.software.name as FediverseProject;
-	} else {
-		throw new Error(`No nodeinfo found for ${domain}`);
-	}
-};
+export type Detection = {
+	domain: string;
+	project: keyof typeof supportedProjects;
+} & ProjectPublishConfig;
 
 export const get: APIRoute = async ({ params }) => {
 	const domain = params.domain as string;
 
-	try {
-		const projectId = await checkNodeInfo(domain);
-
-		if (!PROJECTS.has(projectId)) {
-			throw new Error(`Unexpected project ID: ${projectId}`);
-		}
-		const projectData = PROJECTS.get(projectId) as FediverseProjectData;
-		return new Response(
-			JSON.stringify({
-				host: domain,
-				project: projectId,
-				publishEndpoint: projectData.publishEndpoint,
-				params: projectData.params,
-			}),
-			{
-				status: 200,
-				headers: {
-					"Cache-Control": "public, s-maxage=86400, max-age=604800",
-					"Content-Type": "application/json",
-				},
-			},
-		);
-	} catch {
-		return new Response(JSON.stringify({ error: "Couldn't detect instance" }), {
-			status: 404,
-			headers: {
-				"Content-Type": "application/json",
-			},
-		});
+	const softwareName = await getSoftwareName(domain);
+	if (softwareName === undefined) {
+		return error("Could not detect software; NodeInfo not present.");
 	}
+
+	if (!(softwareName in supportedProjects)) {
+		return error(`"${softwareName}" is not supported yet.`);
+	}
+
+	const publishConfig = supportedProjects[softwareName] as ProjectPublishConfig;
+	return json(
+		{
+			domain,
+			project: softwareName,
+			...publishConfig,
+		},
+		200,
+		{
+			"Cache-Control": "public, s-maxage=86400, max-age=604800",
+		},
+	);
 };
diff --git a/src/pages/api/instances.ts b/src/pages/api/instances.ts
index 131727f..2c1744e 100644
--- a/src/pages/api/instances.ts
+++ b/src/pages/api/instances.ts
@@ -7,70 +7,16 @@
  */
 
 import type { APIRoute } from "astro";
-import { FediverseProject } from "@scripts/constants";
-
-interface ProjectInstance {
-	domain: string;
-	score: number;
-	active_users_monthly: number;
-	total_users: number;
-}
-
-const PROJECTS = Object.values(FediverseProject);
-
-export const fetchInstances = async (
-	projectId: string,
-): Promise<ProjectInstance[]> => {
-	const response = await fetch("https://api.fediverse.observer/", {
-		headers: {
-			Accept: "*/*",
-			"Accept-Language": "en;q=1.0",
-			"Content-Type": "application/json",
-		},
-		referrer: "https://api.fediverse.observer/",
-		body: JSON.stringify({
-			query: `{nodes(status:"UP",softwarename:"${projectId}"){domain score active_users_monthly total_users}}`,
-		}),
-		method: "POST",
-	});
-	const json = await response.json();
-	const instances: ProjectInstance[] = json.data.nodes;
-	return instances.filter(
-		(instance) =>
-			instance.score > 90 &&
-			instance.total_users >= instance.active_users_monthly,
-	);
-};
+import { getPopularInstanceDomains } from "@lib/instance";
+import { json } from "@lib/response";
 
 export const get: APIRoute = async () => {
-	try {
-		const response = await Promise.all(
-			PROJECTS.map((projectId) => fetchInstances(projectId)),
-		);
-		const instances = response.flat();
-		instances.sort((a, b) => {
-			return b.active_users_monthly - a.active_users_monthly;
-		});
+	const popularInstanceDomains = await getPopularInstanceDomains();
 
-		return new Response(
-			JSON.stringify(
-				instances
-					.slice(0, 200)
-					.map((instance: ProjectInstance) => instance.domain),
-			),
-			{
-				headers: {
-					"Cache-Control": "public, s-maxage=86400, max-age=604800",
-					"Content-Type": "application/json",
-				},
-			},
-		);
-	} catch (error) {
-		console.error("Could not fetch instances:", error);
-		return new Response(JSON.stringify([]), {
-			headers: {
-				"Content-Type": "application/json",
-			},
-		});
-	}
+	return json(popularInstanceDomains, 200, {
+		"Cache-Control":
+			popularInstanceDomains.length > 0
+				? "public, s-maxage=86400, max-age=604800"
+				: "public, s-maxage=60, max-age=3600",
+	});
 };
diff --git a/src/pages/api/share.ts b/src/pages/api/share.ts
index cb0b3ed..c94a8a7 100644
--- a/src/pages/api/share.ts
+++ b/src/pages/api/share.ts
@@ -6,8 +6,10 @@
  * SPDX-License-Identifier: AGPL-3.0-only
  */
 
-import { getUrlDomain } from "@scripts/util";
+import { getUrlDomain } from "@lib/url";
 import type { APIRoute } from "astro";
+import type { Detection } from "./detect/[domain]";
+import { error } from "@lib/response";
 
 export const post: APIRoute = async ({ redirect, request, url }) => {
 	const formData = await request.formData();
@@ -16,18 +18,14 @@ export const post: APIRoute = async ({ redirect, request, url }) => {
 	const instanceHost =
 		getUrlDomain(formData.get("instance") as string) || "mastodon.social";
 
-	try {
-		const response = await fetch(new URL(`/api/detect/${instanceHost}`, url));
-		const { host, publishEndpoint, params } = await response.json();
-		const publishUrl = new URL(publishEndpoint, `https://${host}/`);
-		publishUrl.search = new URLSearchParams([[params.text, text]]).toString();
-		return redirect(publishUrl.toString(), 303);
-	} catch {
-		return new Response(JSON.stringify({ error: "Couldn't detect instance" }), {
-			status: 400,
-			headers: {
-				"Content-Type": "application/json",
-			},
-		});
+	const response = await fetch(new URL(`/api/detect/${instanceHost}`, url));
+	const json = await response.json();
+	if (json.error) {
+		return error(json.error);
 	}
+
+	const { domain, endpoint, params } = json as Detection;
+	const publishUrl = new URL(endpoint, `https://${domain}/`);
+	publishUrl.search = new URLSearchParams([[params.text, text]]).toString();
+	return redirect(publishUrl.toString(), 303);
 };
diff --git a/src/scripts/constants.ts b/src/scripts/constants.ts
deleted file mode 100644
index 03f4022..0000000
--- a/src/scripts/constants.ts
+++ /dev/null
@@ -1,28 +0,0 @@
-/*!
- * This file is part of Share₂Fedi
- * https://github.com/kytta/share2fedi
- *
- * SPDX-FileCopyrightText: © 2023 Nikita Karamov <me@kytta.dev>
- * SPDX-License-Identifier: AGPL-3.0-only
- */
-
-/**
- * Enumeration of the supported fediverse projects.
- *
- * The values of this enum are used as the keys for the fediverse.observer API,
- * as the icon names, etc.
- */
-export enum FediverseProject {
-	Calckey = "calckey",
-	GlitchCafe = "glitchcafe",
-	Fedibird = "fedibird",
-	Firefish = "firefish",
-	FoundKey = "foundkey",
-	Friendica = "friendica",
-	GNUSocial = "gnusocial",
-	Hometown = "hometown",
-	Hubzilla = "hubzilla",
-	Mastodon = "mastodon",
-	Meisskey = "meisskey",
-	Misskey = "misskey",
-}
diff --git a/src/stores/saved-instances.ts b/src/stores/saved-instances.ts
index 72c24f2..3a62e06 100644
--- a/src/stores/saved-instances.ts
+++ b/src/stores/saved-instances.ts
@@ -7,7 +7,7 @@
  */
 
 import { persistentAtom } from "@nanostores/persistent";
-import { getUrlDomain } from "@scripts/util";
+import { getUrlDomain } from "@lib/url";
 import { action, onMount } from "nanostores";
 
 const OLD_LOCAL_STORAGE_KEY = "recentInstances";
diff --git a/tsconfig.json b/tsconfig.json
index 0dc6b7b..0392028 100644
--- a/tsconfig.json
+++ b/tsconfig.json
@@ -14,7 +14,7 @@
 			"@i18n/*": ["src/i18n/*"],
 			"@layouts/*": ["src/layouts/*"],
 			"@pages/*": ["src/pages/*"],
-			"@scripts/*": ["src/scripts/*"],
+			"@lib/*": ["src/lib/*"],
 			"@stores/*": ["src/stores/*"],
 			"@styles/*": ["src/styles/*"]
 		}