(core) move home server into core

Summary: This moves enough server material into core to run a home server.  The data engine is not yet incorporated (though in manual testing it works when ported).

Test Plan: existing tests pass

Reviewers: dsagal

Reviewed By: dsagal

Differential Revision: https://phab.getgrist.com/D2552

app/common/EncActionBundle.ts

@@ -0,0 +1,73 @@
+/**
+ * Types for encrypted ActionBundles that get sent between instances and hub.
+ */
+
+import {ActionInfo, Envelope} from 'app/common/ActionBundle';
+import {DocAction} from 'app/common/DocActions';
+
+// Type representing a point in time as milliseconds since Epoch.
+export type Timestamp = number;
+
+// Type representing binary data encoded as a base64 string.
+export type Base64String = string;
+
+// Metadata about a symmetric encryption key.
+export interface KeyInfo {
+  firstActionNum: number;     // ActionNum of first action for which this key was used.
+  firstUsedTime: Timestamp;   // Timestamp of first action for which this key was used.
+}
+
+// Encrypted symmetric key with metadata, sent from hub to instance with each envelope.
+export interface EncKeyInfo extends KeyInfo {
+  encryptedKey: Base64String; // Symmetric key encrypted with the recipient's public key.
+}
+
+// Bundle of encryptions of the symmetric key. Note that the hub will store EncKeyBundles for
+// lookup, indexed by the combination {recipients: string[], firstActionNum: number}.
+export interface EncKeyBundle extends KeyInfo {
+  encryptedKeys: {
+    // Map of instanceId to the symmetric key encrypted with that instance's public key.
+    // A single symmetric key is used for all, and only present here in encrypted form.
+    [instanceId: string]: Base64String;
+  };
+}
+
+// This allows reorganizing ActionBundle by envelope while preserving order information for
+// actions. E.g. if ActionBundle contains {stored: [(0,A), (1,B), (2,C), (0,D)], then we'll have:
+//    - in envelopes 0: {stored: [[0, A], [3, D]]}
+//    - in envelopes 1: {stored: [[1, B]]}
+//    - in envelopes 2: {stored: [[2, C]]}
+// Then recipients of multiple envelopes can sort actions by index to get their correct order.
+export interface DecryptedEnvelopeContent {
+  info?: ActionInfo;
+  // number is the index into the bundle-wide array of 'stored' or 'calc' DocActions.
+  stored: Array<[number, DocAction]>;
+  calc: Array<[number, DocAction]>;
+}
+
+export type DecryptedEnvelope = Envelope & DecryptedEnvelopeContent;
+
+// Sent from instance to hub.
+export interface EncEnvelopeToHub extends Envelope {
+  encKeyReused?: number;        // If reusing a key, firstActionNum of the key being reused.
+  encKeyBundle?: EncKeyBundle;  // If created a new key, its encryption for all recipients.
+  content: Base64String;        // Marshalled and encrypted DecryptedEnvelopeContent as a base64 string.
+}
+
+// Sent from hub to instance.
+export interface EncEnvelopeFromHub extends Envelope {
+  encKeyInfo: EncKeyInfo;
+  content: Base64String;        // Marshalled and encrypted DecryptedEnvelopeContent as a base64 string.
+}
+
+// EncActionBundle is an encrypted version of ActionBundle. It comes in two varieties, one for
+// sending ActionBundle to the hub, and one for receiving from the hub.
+export interface EncActionBundle<EncEnvelope> {
+  actionNum: number;
+  actionHash: string|null;
+  parentActionHash: string|null;
+  envelopes: EncEnvelope[];
+}
+
+export type EncActionBundleToHub = EncActionBundle<EncEnvelopeToHub>;
+export type EncActionBundleFromHub = EncActionBundle<EncEnvelopeFromHub>;