refactor: look up fetch options per request

.gitignore

@@ -1,2 +1,2 @@
 /node_modules/
-/dl-*.fetch-options.json
+/fetch-options.*.json

README.md

@@ -1,13 +1,13 @@
 # dl-fur
 
-## `dl-*.fetch-options.json`
+## `fetch-options.*.json`
 
-Each `dl-*.js` will look for a corresponding `dl-*.fetch-options.json` and, if present, will use it as the second argument in all `fetch` calls.
+Each request will look for a corresponding `fetch-options.[hostname].json` and, if present, will use it as the second argument in all `fetch` calls.
 
 For example, if you have a `cf_clearance` cookie for the Cloudflare protection in front of FurryBooru, you can create
 
 ```json
-// dl-furrybooru.fetch-options.json
+// fetch-options.furry.booru.org.json
 {
 	"headers": {
 		"cookie": "cf_clearance=whatever",

_dl.js

@@ -25,12 +25,16 @@ const make_query = (params) => {
 	return str && `?${str}`;
 };
 
-export const dl = async ({ from, get_posts }) => {
-	const fetch_options = await fs.promises.readFile(new URL(from.slice(0, -3) + '.fetch-options.json'), 'utf8').then(JSON.parse, () => {});
+const fetch_options_lookup = {};
+const get_fetch_options = url => {
+	const { hostname } = new URL(url);
+	return fetch_options_lookup[hostname] ??= fs.promises.readFile(new URL(`./fetch-options.${hostname}.json`, import.meta.url), 'utf8').then(JSON.parse, () => {});
+};
 
+export const dl = async get_posts => {
 	for (const query of process.argv.slice(2)) {
 		const posts = [];
-		for await (const page of get_posts(query, (url, params) => fetch_200(url + make_query(params), fetch_options))) {
+		for await (const page of get_posts(query, async (url, params) => fetch_200(url + make_query(params), await get_fetch_options(url)))) {
 			posts.push(...page);
 			console.log(`\x1b[K${query}: ${posts.length} posts\x1b[A`);
 		}
@@ -42,7 +46,7 @@ export const dl = async ({ from, get_posts }) => {
 				await fs.promises.access(dest);
 			} catch {
 				console.log(`${i + 1}/${posts.length}: ${dest}`);
-				const resp = await fetch_200(url, fetch_options);
+				const resp = await fetch_200(url, await get_fetch_options(url));
 				const buffer = Buffer.from(await resp.arrayBuffer());
 				const tmp = crypto.randomUUID();
 				await fs.promises.writeFile(tmp, buffer);

dl-e621.js

@@ -2,9 +2,8 @@
 
 import { dl } from './_dl.js';
 
-await dl({
-	from: import.meta.url,
-	async *get_posts(query, get) {
+await dl(
+	async function*(query, get) {
 		for (let page = null, posts; !posts || posts.length === 320; page = `b${posts[319]?.id}`) {
 			posts = (await (await get('https://e621.net/posts.json', { limit: 320, page, tags: query })).json()).posts;
 			yield posts.map(post => ({
@@ -14,4 +13,4 @@ await dl({
 			}));
 		}
 	},
-});
+);

dl-furrybooru.js

@@ -2,9 +2,8 @@
 
 import { dl } from './_dl.js';
 
-await dl({
-	from: import.meta.url,
-	async *get_posts(query, get) {
+await dl(
+	async function*(query, get) {
 		for (let pid = 0, posts; !posts || posts.length === 100; pid++) {
 			posts = (await (await get('https://furry.booru.org/index.php', { page: 'dapi', s: 'post', q: 'index', limit: 100, pid, tags: query })).text()).match(/<post\b.*?\/>/gs) || [];
 			yield posts.map(post => {
@@ -15,4 +14,4 @@ await dl({
 			});
 		}
 	},
-});
+);