myst-cli/dist/utils/fetchRemoteAsset.js

Command line tools for MyST

import fs from 'node:fs';
import nodePath from 'node:path';
import mime from 'mime-types';
import { EXT_REQUEST_HEADERS } from '../utils/headers.js';
function rewriteGitHubURL(url) {
    const GITHUB_BLOB = /^(?:https?:\/\/)?github\.com\/([^/]+)\/([^/]+)\/blob\//;
    return url.replace(GITHUB_BLOB, 'https://raw.githubusercontent.com/$1/$2/');
}
/**
 * Fetch remote asset and write to disk.
 *
 * @param session session object
 * @param url remote URL to fetch
 * @param path destination directory to write to
 * @param stem filename stem for the target file
 */
export async function fetchRemoteAsset(session, url, path, stem, opts) {
    const finalURL = rewriteGitHubURL(url);
    const res = await session.fetch(finalURL, { headers: EXT_REQUEST_HEADERS });
    let extension;
    let contentType;
    // Prefer provided extension
    if (opts?.extension !== undefined) {
        extension = opts.extension;
        // Determine content-type for this extension
        const extMimeType = mime.contentType(extension);
        if (extMimeType === false) {
            throw new Error(`Unknown content-type found for extension ${extension}.`);
        }
        contentType = extMimeType;
    }
    else {
        const rawContentType = res.headers.get('content-type');
        if (rawContentType === null) {
            throw new Error(`Unknown content-type found for URL ${url}.`);
        }
        contentType = rawContentType;
        const mimeExt = mime.extension(contentType);
        if (mimeExt === false) {
            throw new Error(`Unknown content-type found for extension ${mimeExt}.`);
        }
        extension = mimeExt;
    }
    //
    // Ensure that destination directory exists
    if (!fs.existsSync(path)) {
        fs.mkdirSync(path, { recursive: true });
    }
    const destName = `${stem}.${extension}`;
    const destPath = nodePath.join(path, destName);
    // Write to a file
    const fileStream = fs.createWriteStream(destPath);
    await new Promise((resolve, reject) => {
        if (!res.body) {
            reject(`no response body from ${finalURL}`);
        }
        else {
            res.body.pipe(fileStream);
            res.body.on('error', reject);
            fileStream.on('finish', resolve);
        }
    });
    await new Promise((r) => setTimeout(r, 50));
    session.log.debug(`Asset successfully saved to: ${destName}`);
    return { name: destName, contentType };
}