feat: preview from source bus

package.json

@@ -54,6 +54,7 @@
     "@adobe/helix-admin-support": "5.0.3",
     "@adobe/helix-config": "5.7.0",
     "@adobe/helix-google-support": "4.0.1",
+    "@adobe/helix-html2md": "1.1.0",
     "@adobe/helix-mediahandler": "2.9.5",
     "@adobe/helix-onedrive-support": "12.1.5",
     "@adobe/helix-shared-body-data": "2.2.3",

src/contentproxy/errors.js

@@ -58,6 +58,10 @@ const errors = [
     code: 'AEM_BACKEND_FILE_TOO_BIG',
     template: 'Unable to preview \'$1\': Documents larger than 100mb not supported: $2',
   },
+  {
+    code: 'AEM_BACKEND_TOO_MANY_IMAGES',
+    template: 'Unable to preview \'$1\': Documents has more than $2 images: $3',
+  },
   {
     code: 'AEM_BACKEND_RESOURCE_TOO_BIG',
     template: 'Files larger than 500mb are not supported: $1',

src/contentproxy/index.js

@@ -17,6 +17,7 @@ import { error } from './errors.js';
 import google from './google.js';
 import markup from './markup.js';
 import onedrive from './onedrive.js';
+import sourcebus from './sourcebus.js';
 
 /**
  * @type {import('./contentproxy').ContentSourceHandler[]}
@@ -25,6 +26,7 @@ export const HANDLERS = { // exported for testing only
   google,
   onedrive,
   markup,
+  sourcebus,
 };
 
 /**
@@ -34,7 +36,11 @@ export const HANDLERS = { // exported for testing only
  * @return {import('./contentproxy').ContentSourceHandler} handler
  */
 export function getContentSourceHandler(source) {
-  return HANDLERS[source.type];
+  let { type } = source;
+  if (source.url?.startsWith('https://api.aem.live/')) {
+    type = 'sourcebus';
+  }
+  return HANDLERS[type];
 }
 
 /**

src/contentproxy/sourcebus.js

@@ -0,0 +1,157 @@
+/*
+ * Copyright 2025 Adobe. All rights reserved.
+ * This file is licensed to you under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License. You may obtain a copy
+ * of the License at https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software distributed under
+ * the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR REPRESENTATIONS
+ * OF ANY KIND, either express or implied. See the License for the specific language
+ * governing permissions and limitations under the License.
+ */
+import { HelixStorage } from '@adobe/helix-shared-storage';
+import { MediaHandler, SizeTooLargeException } from '@adobe/helix-mediahandler';
+import { ConstraintsError, html2md, TooManyImagesError } from '@adobe/helix-html2md';
+import { Response } from '@adobe/fetch';
+import { errorResponse } from '../support/utils.js';
+import { error } from './errors.js';
+
+const DEFAULT_MAX_IMAGE_SIZE = 20 * 1024 * 1024; // 20mb
+
+const DEFAULT_MAX_IMAGES = 200;
+
+/**
+ * Retrieves a file from source bus.
+ *
+ * @param {import('../support/AdminContext').AdminContext} ctx context
+ * @param {import('../support/RequestInfo').RequestInfo} info request info
+ * @param {object} [opts] options
+ * @param {object} [opts.source] content source
+ * @param {string} [opts.lastModified] last modified
+ * @param {number} [opts.fetchTimeout] fetch timeout
+ * @returns {Promise<Response>} response
+ */
+async function handle(ctx, info, opts) {
+  const { config: { content, limits }, log } = ctx;
+
+  const source = opts?.source ?? content.source;
+  const sourceUrl = new URL(source.url);
+  // extract org and site from url.pathname, format: https://api.aem.live/<org>/sites/<site>/source
+  // e.g. /adobe/sites/foo/source
+  const pathMatch = sourceUrl.pathname.match(/^\/([^/]+)\/sites\/([^/]+)\/source$/);
+  if (!pathMatch) {
+    return errorResponse(log, 400, error(
+      'Source url must be in the format: https://api.aem.live/<org>/sites/<site>/source. Got: $1',
+      sourceUrl.href,
+    ));
+  }
+  const [, org, site] = pathMatch; // eslint-disable-line prefer-destructuring
+
+  // for now, only allow source bus from the same org and site
+  if (org !== info.org || site !== info.site) {
+    return errorResponse(log, 400, error(
+      'Source bus is not allowed for org: $1, site: $2',
+      org,
+      site,
+    ));
+  }
+  // the source is stored as .html files in the source bus
+  let sourcePath = info.resourcePath;
+  if (info.ext === '.md') {
+    sourcePath = `${sourcePath.substring(0, sourcePath.length - '.md'.length)}.html`;
+    /* c8 ignore next 7 */
+  } else {
+    // this should never happen, since all resourcePaths are properly mapped before
+    return errorResponse(log, 400, error(
+      'unexpected file extension: $1',
+      info.ext,
+    ));
+  }
+
+  // load content from source bus
+  const sourceBus = HelixStorage.fromContext(ctx).sourceBus();
+  const meta = {};
+  const body = await sourceBus.get(`${org}/${site}${sourcePath}`, meta);
+  if (!body) {
+    return new Response('', { status: 404 });
+  }
+
+  const {
+    MEDIAHANDLER_NOCACHHE: noCache,
+    CLOUDFLARE_ACCOUNT_ID: r2AccountId,
+    CLOUDFLARE_R2_ACCESS_KEY_ID: r2AccessKeyId,
+    CLOUDFLARE_R2_SECRET_ACCESS_KEY: r2SecretAccessKey,
+  } = ctx.env;
+
+  const mediaHandler = new MediaHandler({
+    r2AccountId,
+    r2AccessKeyId,
+    r2SecretAccessKey,
+    bucketId: ctx.attributes.bucketMap.media,
+    owner: org,
+    repo: site,
+    ref: 'main',
+    contentBusId: content.contentBusId,
+    log,
+    noCache,
+    fetchTimeout: 5000, // limit image fetches to 5s
+    forceHttp1: true,
+    maxSize: limits?.html2md?.maxImageSize ?? DEFAULT_MAX_IMAGE_SIZE,
+  });
+
+  const maxImages = limits?.html2md?.maxImages ?? DEFAULT_MAX_IMAGES;
+  try {
+    // convert to md
+    const md = await html2md(body, {
+      mediaHandler,
+      log,
+      url: sourceUrl.href + sourcePath, // only used for logging
+      org,
+      site,
+      unspreadLists: true,
+      maxImages,
+      externalImageUrlPrefixes: [`https://main--${site}--${org}.aem.page/`],
+    });
+
+    return new Response(md, {
+      status: 200,
+      headers: {
+        'content-type': 'text/markdown',
+        'last-modified': meta.LastModified?.toUTCString(),
+      },
+    });
+  } catch (e) {
+    if (e instanceof TooManyImagesError) {
+      return errorResponse(log, 409, error(
+        'Unable to preview \'$1\': Documents has more than $2 images: $3',
+        sourcePath,
+        maxImages,
+        e.message, // todo: include num images in error
+      ));
+    }
+    if (e instanceof SizeTooLargeException) {
+      return errorResponse(log, 409, error(
+        'Unable to preview \'$1\': $2',
+        sourcePath,
+        e.message,
+      ));
+    }
+    /* c8 ignore next 6 */
+    return errorResponse(log, 500, error(
+      'Unable to preview \'$1\': $2',
+      sourcePath,
+      e.message,
+    ));
+  }
+}
+
+/**
+ * @type {import('./contentproxy.js').ContentSourceHandler}
+ */
+export default {
+  name: 'sourcebus',
+  handle,
+  handleJSON: () => { throw new Error('not implemented'); },
+  handleFile: () => { throw new Error('not implemented'); },
+  list: () => { throw new Error('not implemented'); },
+};

test/contentproxy/fixtures/sourcebus/gallery.html

@@ -0,0 +1,14 @@
+<html>
+    <head></head>
+    <body>
+        <main>
+            <div>
+                <h1>Hello, world.</h1>
+                <p>source bus images.</p>
+                <img src="https://www.example.com/image1.jpg">
+                <img src="https://www.example.com/image2.jpg">
+                <img src="https://main--site--org.aem.page/media_2c2e2c6c049ccf4b583431e14919687f3a39cc227.png#width=300&height=300">
+            </div>
+        </main>
+    </body>
+</html>

test/contentproxy/fixtures/sourcebus/index.html

@@ -0,0 +1,11 @@
+<html>
+    <head></head>
+    <body>
+        <main>
+            <div>
+                <h1>Hello, world.</h1>
+                <p>Testing, source bus.</p>
+            </div>
+        </main>
+    </body>
+</html>

test/contentproxy/fixtures/sourcebus/welcome.html

@@ -0,0 +1,11 @@
+<html>
+    <head></head>
+    <body>
+        <main>
+            <div>
+                <h1>Hello, world.</h1>
+                <p>Testing, source bus.</p>
+            </div>
+        </main>
+    </body>
+</html>