Implement utility function on the keyserver to upload notification pa…

…yload to blob service

Summary:
This differential introduces utility function on the keyserver that AES-encrypts notification payload and uploads it to the keyserver. Changes in eslint configuration that are necessary for native node fetch API usage are introduced as
well.

Test Plan:
1. Launch blob service locally.
2. Modify `blob-service.js` file in `facts` directory to point to local IP address
3. Modify `send.js` file to execute this method on the stringified Android notification payload and log output to the console.
4. Send notification to Android device. Examine logs from keyserver and blob service terminals.

Reviewers: bartek, tomek, kamil

Reviewed By: bartek

Subscribers: michal, ashoat

Differential Revision: https://phab.comm.dev/D8529

keyserver/.eslintrc.json

@@ -2,5 +2,8 @@
   "env": {
     "node": true,
     "jest": true
+  },
+  "globals": {
+    "Blob": false
   }
 }

keyserver/src/push/utils.js

@@ -1,17 +1,25 @@
 // @flow
 
 import type { ResponseFailure } from '@parse/node-apn';
+import crypto from 'crypto';
 import type { FirebaseApp, FirebaseError } from 'firebase-admin';
 import invariant from 'invariant';
+import nodeFetch from 'node-fetch';
+import type { Response } from 'node-fetch';
+import uuid from 'uuid';
 import webpush from 'web-push';
 
+import blobService from 'lib/facts/blob-service.js';
 import type { PlatformDetails } from 'lib/types/device-types.js';
 import type {
   WebNotification,
   WNSNotification,
 } from 'lib/types/notif-types.js';
 import { threadSubscriptions } from 'lib/types/subscription-types.js';
 import { threadPermissions } from 'lib/types/thread-permission-types.js';
+import { toBase64URL } from 'lib/utils/base64.js';
+import { makeBlobServiceEndpointURL } from 'lib/utils/blob-service.js';
+import { getMessageForException } from 'lib/utils/errors.js';
 
 import {
   getAPNPushProfileForCodeVersion,
@@ -26,6 +34,7 @@ import type {
   TargetedAndroidNotification,
 } from './types.js';
 import { dbQuery, SQL } from '../database/database.js';
+import { generateKey, encrypt } from '../utils/aes-crypto-utils.js';
 
 const fcmTokenInvalidationErrors = new Set([
   'messaging/registration-token-not-registered',
@@ -352,7 +361,7 @@ async function wnsSinglePush(token: string, notification: string, url: string) {
   }
 
   try {
-    const result = await fetch(url, {
+    const result = await nodeFetch(url, {
       method: 'POST',
       headers: {
         'Content-Type': 'application/octet-stream',
@@ -375,8 +384,91 @@ async function wnsSinglePush(token: string, notification: string, url: string) {
   }
 }
 
+async function blobServiceUpload(payload: string): Promise<
+  | {
+      +blobHash: string,
+      +encryptionKey: string,
+    }
+  | { +blobUploadError: string },
+> {
+  const encryptionKey = await generateKey();
+  const encryptedPayloadBuffer = Buffer.from(
+    await encrypt(encryptionKey, new TextEncoder().encode(payload)),
+  );
+
+  const blobHolder = uuid.v4();
+  const blobHashBase64 = await crypto
+    .createHash('sha256')
+    .update(encryptedPayloadBuffer)
+    .digest('base64');
+
+  const blobHash = toBase64URL(blobHashBase64);
+
+  const formData = new FormData();
+  const payloadBlob = new Blob([encryptedPayloadBuffer]);
+
+  formData.append('blob_hash', blobHash);
+  formData.append('blob_data', payloadBlob);
+
+  const assignHolderPromise = fetch(
+    makeBlobServiceEndpointURL(blobService.httpEndpoints.ASSIGN_HOLDER),
+    {
+      method: blobService.httpEndpoints.ASSIGN_HOLDER.method,
+      body: JSON.stringify({
+        holder: blobHolder,
+        blob_hash: blobHash,
+      }),
+      headers: {
+        'content-type': 'application/json',
+      },
+    },
+  );
+
+  const uploadHolderPromise = fetch(
+    makeBlobServiceEndpointURL(blobService.httpEndpoints.UPLOAD_BLOB),
+    {
+      method: blobService.httpEndpoints.UPLOAD_BLOB.method,
+      body: formData,
+    },
+  );
+
+  try {
+    const [assignHolderResponse, uploadBlobResponse] = await Promise.all([
+      assignHolderPromise,
+      uploadHolderPromise,
+    ]);
+
+    if (!assignHolderResponse.ok) {
+      const { status, statusText } = assignHolderResponse;
+      return {
+        blobUploadError: `Holder assignment failed with HTTP ${status}: ${statusText}`,
+      };
+    }
+
+    if (!uploadBlobResponse.ok) {
+      const { status, statusText } = uploadBlobResponse;
+      return {
+        blobUploadError: `Payload upload failed with HTTP ${status}: ${statusText}`,
+      };
+    }
+  } catch (e) {
+    return {
+      blobUploadError: `Payload upload failed with: ${
+        getMessageForException(e) ?? 'unknown error'
+      }`,
+    };
+  }
+
+  const encryptionKeyString = Buffer.from(encryptionKey).toString('base64');
+  return {
+    blobHash,
+    encryptionKey: encryptionKeyString,
+  };
+}
+
 export {
   apnPush,
+  blobServiceUpload,
   fcmPush,
   webPush,
   wnsPush,