feat(create-waku): --example option

packages/create-waku/package.json

@@ -25,16 +25,18 @@
     "start": "node ./dist/index.js",
     "dev": "ncc build ./src/index.ts -w -o ./dist/",
     "compile": "rm -rf template dist *.tsbuildinfo && pnpm run template && pnpm run build",
-    "template": "cp -r ../../examples template/ && rm -rf template/*/dist && rm -rf template/*/node_modules && mv template/01_template/.gitignore template/01_template/gitignore",
+    "template": "mkdir template && cp -r ../../examples/01_template template/01_template && rm -rf template/*/dist && rm -rf template/*/node_modules && mv template/01_template/.gitignore template/01_template/gitignore",
     "build": "ncc build ./src/index.ts -o ./dist/ --minify --no-cache --no-source-map-register"
   },
   "devDependencies": {
     "@types/fs-extra": "^11.0.4",
     "@types/prompts": "^2.4.9",
+    "@types/tar": "^6.1.11",
     "@vercel/ncc": "^0.38.1",
     "fs-extra": "^11.2.0",
     "kolorist": "^1.8.0",
     "prompts": "^2.4.2",
+    "tar": "^6.2.0",
     "update-check": "^1.5.4"
   }
 }

packages/create-waku/src/helpers/example-option.ts

@@ -0,0 +1,130 @@
+import * as tar from 'tar';
+import { Readable } from 'node:stream';
+import { pipeline } from 'node:stream/promises';
+import type { ReadableStream } from 'stream/web';
+
+export type RepoInfo = {
+  username: string | undefined;
+  name: string | undefined;
+  branch: string | undefined;
+  filePath: string | undefined;
+};
+
+export async function isUrlOk(url: string): Promise<boolean> {
+  try {
+    const res = await fetch(url, { method: 'HEAD' });
+    return res.status === 200;
+  } catch {
+    return false;
+  }
+}
+
+/**
+ * this is a part of the response type for github "Get a repository" API
+ * @see {@link https://docs.github.com/en/rest/repos/repos?apiVersion=2022-11-28#get-a-repository|GitHub REST API}
+ */
+interface GetRepoInfo {
+  /** A default branch of the repository */
+  default_branch: string;
+}
+export async function getRepoInfo(url: URL): Promise<RepoInfo | undefined> {
+  const [, username, name, t, _branch, ...file] = url.pathname.split('/');
+  const filePath = file.join('/');
+
+  if (
+    // Support repos whose entire purpose is to be a waku example, e.g.
+    // https://github.com/:username/:my-cool-waku-example-repo-name.
+    t === undefined ||
+    // Support GitHub URL that ends with a trailing slash, e.g.
+    // https://github.com/:username/:my-cool-waku-example-repo-name/
+    // In this case "t" will be an empty string while the next part "_branch" will be undefined
+    (t === '' && _branch === undefined)
+  ) {
+    try {
+      const infoResponse = await fetch(
+        `https://api.github.com/repos/${username}/${name}`,
+      );
+      if (infoResponse.status !== 200) {
+        return;
+      }
+
+      const info = (await infoResponse.json()) as GetRepoInfo;
+      return { username, name, branch: info['default_branch'], filePath };
+    } catch {
+      return;
+    }
+  }
+
+  if (username && name && _branch && t === 'tree') {
+    return { username, name, branch: _branch, filePath };
+  }
+}
+
+export function hasRepo({
+  username,
+  name,
+  branch,
+  filePath,
+}: RepoInfo): Promise<boolean> {
+  const contentsUrl = `https://api.github.com/repos/${username}/${name}/contents`;
+  const packagePath = `${filePath ? `/${filePath}` : ''}/package.json`;
+
+  return isUrlOk(contentsUrl + packagePath + `?ref=${branch}`);
+}
+
+export function existsInRepo(nameOrUrl: string): Promise<boolean> {
+  try {
+    const url = new URL(nameOrUrl);
+    return isUrlOk(url.href);
+  } catch {
+    return isUrlOk(
+      `https://api.github.com/repos/dai-shi/waku/contents/examples/${encodeURIComponent(
+        nameOrUrl,
+      )}`,
+    );
+  }
+}
+
+async function downloadTarStream(url: string) {
+  const res = await fetch(url);
+
+  if (!res.body) {
+    throw new Error(`Failed to download: ${url}`);
+  }
+
+  return Readable.fromWeb(res.body as ReadableStream);
+}
+
+export async function downloadAndExtractRepo(
+  root: string,
+  { username, name, branch, filePath }: RepoInfo,
+) {
+  await pipeline(
+    await downloadTarStream(
+      `https://codeload.github.com/${username}/${name}/tar.gz/${branch}`,
+    ),
+    tar.x({
+      cwd: root,
+      strip: filePath ? filePath.split('/').length + 1 : 1,
+      filter: (p) =>
+        p.startsWith(
+          `${name}-${branch?.replace(/\//g, '-')}${
+            filePath ? `/${filePath}/` : '/'
+          }`,
+        ),
+    }),
+  );
+}
+
+export async function downloadAndExtractExample(root: string, name: string) {
+  await pipeline(
+    await downloadTarStream(
+      'https://codeload.github.com/dai-shi/waku/tar.gz/main',
+    ),
+    tar.x({
+      cwd: root,
+      strip: 2 + name.split('/').length,
+      filter: (p) => p.includes(`waku-main/examples/${name}/`),
+    }),
+  );
+}