From 3e2ef8b1ea0f0b05a08026fb4202ba185f37c28f Mon Sep 17 00:00:00 2001
From: nitro-neal <5314059+nitro-neal@users.noreply.github.com>
Date: Tue, 21 May 2024 09:21:10 -0700
Subject: [PATCH] Web Features (@cswildcat) (#567)

* Add new web features module with networking feature installation

* Update configs

* Make TS happy

* Make TS happy, part 2

* TS and linting joy

* put web5-spec on main

* update

---------

Co-authored-by: Daniel Buchner <danieljb2@gmail.com>
---
 packages/api/src/index.ts          |  1 +
 packages/api/src/service-worker.ts | 55 ++++++++++++++++++++++++++++++
 packages/api/src/web-features.ts   | 25 ++++++++++++++
 packages/api/tsconfig.json         |  4 +++
 4 files changed, 85 insertions(+)
 create mode 100644 packages/api/src/service-worker.ts
 create mode 100644 packages/api/src/web-features.ts

diff --git a/packages/api/src/index.ts b/packages/api/src/index.ts
index 9c420aba6..30e46b9c1 100644
--- a/packages/api/src/index.ts
+++ b/packages/api/src/index.ts
@@ -28,6 +28,7 @@ export * from './record.js';
 export * from './vc-api.js';
 export * from './web5.js';
 export * from './tech-preview.js';
+export * from './web-features.js';
 
 import * as utils from './utils.js';
 export { utils };
\ No newline at end of file
diff --git a/packages/api/src/service-worker.ts b/packages/api/src/service-worker.ts
new file mode 100644
index 000000000..7ca3eff6b
--- /dev/null
+++ b/packages/api/src/service-worker.ts
@@ -0,0 +1,55 @@
+import { UniversalResolver, DidDht, DidWeb } from '@web5/dids';
+
+const workerSelf = self as any;
+const DidResolver = new UniversalResolver({ didResolvers: [DidDht, DidWeb] });
+const didUrlRegex = /^https?:\/\/dweb\/(([^/]+)\/.*)?$/;
+const httpToHttpsRegex = /^http:/;
+const trailingSlashRegex = /\/$/;
+
+workerSelf.addEventListener('fetch', event => {
+  const match = event.request.url.match(didUrlRegex);
+  if (match) {
+    event.respondWith((async () => {
+      const normalizedUrl = event.request.url.replace(httpToHttpsRegex, 'https:').replace(trailingSlashRegex, '');
+      const cachedResponse = await caches.open('drl').then(cache => cache.match(normalizedUrl));
+      return cachedResponse || handleEvent(event, match[2], match[1]);
+    })());
+  }
+});
+
+async function handleEvent(event, did, route){
+  try {
+    const result = await DidResolver.resolve(did);
+    return await fetchResource(event, result.didDocument, route);
+  }
+  catch(error){
+    if (error instanceof Response) {
+      return error;
+    }
+    console.log(`Error in DID URL fetch: ${error}`);
+    return new Response('DID URL fetch error', { status: 500 });
+  }
+}
+
+async function fetchResource(event, ddo, route) {
+  let endpoints = ddo?.service?.find(service => service.type === 'DecentralizedWebNode')?.serviceEndpoint;
+  endpoints = (Array.isArray(endpoints) ? endpoints : [endpoints]).filter(url => url.startsWith('http'));
+  if (!endpoints?.length) {
+    throw new Response('DWeb Node resolution failed: no valid endpoints found.', { status: 530 });
+  }
+
+  for (const endpoint of endpoints) {
+    try {
+      const response = await fetch(`${endpoint.replace(trailingSlashRegex, '')}/${route}`, { headers: event.request.headers });
+      if (response.ok) {
+        return response;
+      }
+      console.log(`DWN endpoint error: ${response.status}`);
+      return new Response('DWeb Node request failed', { status: response.status });
+    }
+    catch (error) {
+      console.log(`DWN endpoint error: ${error}`);
+      return new Response('DWeb Node request failed: ' + error, { status: 500 });
+    }
+  }
+}
\ No newline at end of file
diff --git a/packages/api/src/web-features.ts b/packages/api/src/web-features.ts
new file mode 100644
index 000000000..e264b0b08
--- /dev/null
+++ b/packages/api/src/web-features.ts
@@ -0,0 +1,25 @@
+
+declare const ServiceWorkerGlobalScope: any;
+
+export function installNetworkingFeatures(path: string): void {
+  const workerSelf = self as any;
+
+  try {
+    if (typeof ServiceWorkerGlobalScope !== 'undefined' && workerSelf instanceof ServiceWorkerGlobalScope) {
+      // Dynamically import service worker code only if we're in a Service Worker context
+      import('./service-worker.js').catch(error => {
+        console.error('Error loading service worker module:', error);
+      });
+    }
+    else if (globalThis?.navigator?.serviceWorker) {
+      if (path) navigator.serviceWorker.register(path).catch(error => {
+        console.error('DWeb networking feature installation failed: ', error);
+      });
+    }
+    else {
+      throw new Error('DWeb networking features are not available for install in this environment');
+    }
+  } catch (error) {
+    console.error('Error in installing networking features:', error);
+  }
+}
\ No newline at end of file
diff --git a/packages/api/tsconfig.json b/packages/api/tsconfig.json
index 0701f4d02..8b5a11c1c 100644
--- a/packages/api/tsconfig.json
+++ b/packages/api/tsconfig.json
@@ -1,6 +1,10 @@
 {
   "extends": "../../tsconfig.json",
   "compilerOptions": {
+    "lib": [
+      "DOM",
+      "ES2022"
+    ],
     "strict": false,
     "declarationDir": "dist/types",
     "outDir": "dist/esm"