Add bounded memory and IndexedDB storage

package.json

@@ -22,7 +22,6 @@
     "@contextvm/sdk": "0.12.0",
     "@noble/ciphers": "2.2.0",
     "@noble/secp256k1": "3.1.0",
-    "@sqlite.org/sqlite-wasm": "3.53.0-build1",
     "nostr-tools": "2.23.5",
     "svelte": "5.56.3",
     "ts-mls": "2.0.0-rc.12",

src/components/RelayConfigPanel.svelte

@@ -61,6 +61,16 @@
     const input = event.currentTarget as HTMLInputElement;
     config.setMaxUsers(input.valueAsNumber);
   }
+
+  function updateStorageBackend(event: Event): void {
+    const input = event.currentTarget as HTMLSelectElement;
+    config.setStorageBackend(input.value);
+  }
+
+  function updateMessageBufferLimit(event: Event): void {
+    const input = event.currentTarget as HTMLInputElement;
+    config.setMessageBufferLimit(input.valueAsNumber);
+  }
 </script>
 
 <section class="mx-auto max-w-3xl py-8">
@@ -152,7 +162,7 @@
     <div class="mb-4 flex items-center justify-between gap-4">
       <h3 class="text-xs uppercase tracking-[0.18em] text-[#87ff9f]">Runtime options</h3>
       <span class="border border-[#21482b] px-3 py-1 text-xs uppercase text-[#a7b0aa]" data-testid="max-users-state">
-        {config.maxUsers} key packages / identity
+        {config.storageBackend} storage · {config.messageBufferLimit} buffered · {config.maxUsers} key packages / identity
       </span>
     </div>
 
@@ -184,6 +194,37 @@
           onchange={updateMaxUsers}
         />
       </label>
+
+      <label class="grid gap-2 border border-[#16331f] bg-[#050805] p-3 text-sm text-[#d1ffd9]">
+        <span class="uppercase tracking-[0.12em] text-[#6d746f]">storage</span>
+        <select
+          class="border border-[#21482b] bg-black px-3 py-2 text-[#87ff9f] outline-none focus:border-[#87ff9f] disabled:cursor-not-allowed disabled:text-[#4b554e]"
+          value={config.storageBackend}
+          disabled={!editingAllowed}
+          aria-label="Storage backend"
+          data-testid="storage-backend-select"
+          onchange={updateStorageBackend}
+        >
+          <option value="memory">memory</option>
+          <option value="indexeddb">IndexedDB</option>
+        </select>
+      </label>
+
+      <label class="grid gap-2 border border-[#16331f] bg-[#050805] p-3 text-sm text-[#d1ffd9]">
+        <span class="uppercase tracking-[0.12em] text-[#6d746f]">message buffer</span>
+        <input
+          class="border border-[#21482b] bg-black px-3 py-2 text-[#87ff9f] outline-none focus:border-[#87ff9f] disabled:cursor-not-allowed disabled:text-[#4b554e]"
+          type="number"
+          min="1"
+          max="50000"
+          step="1"
+          value={config.messageBufferLimit}
+          disabled={!editingAllowed}
+          aria-label="Message buffer"
+          data-testid="message-buffer-input"
+          onchange={updateMessageBufferLimit}
+        />
+      </label>
     </div>
 
     {#if config.limitError}

src/config/config-validator.ts

@@ -1,3 +1,9 @@
+import {
+  MAX_MEMORY_MESSAGE_BUFFER_LIMIT,
+  MIN_MEMORY_MESSAGE_BUFFER_LIMIT,
+} from "../cordn/coordinator/storage/inMemoryStorage";
+import type { BrowserCoordinatorStorageBackend } from "../cordn/coordinator/storage/browserCoordinatorStorage";
+
 export function validateRelayUrl(value: string): string | null {
   const trimmed = value.trim();
   if (trimmed.length === 0) {
@@ -25,6 +31,7 @@ export function validateRelayUrl(value: string): string | null {
 export const MIN_MAX_USERS = 1;
 export const DEFAULT_MAX_USERS = 64;
 export const BROWSER_MAX_USERS_CAP = 256;
+export const DEFAULT_STORAGE_BACKEND: BrowserCoordinatorStorageBackend = "memory";
 
 export function validateMaxUsers(value: number): string | null {
   if (!Number.isSafeInteger(value)) {
@@ -41,3 +48,25 @@ export function validateMaxUsers(value: number): string | null {
 
   return null;
 }
+
+export function validateStorageBackend(
+  value: string,
+): value is BrowserCoordinatorStorageBackend {
+  return value === "memory" || value === "indexeddb";
+}
+
+export function validateMessageBufferLimit(value: number): string | null {
+  if (!Number.isSafeInteger(value)) {
+    return "Message buffer must be a whole number";
+  }
+
+  if (value < MIN_MEMORY_MESSAGE_BUFFER_LIMIT) {
+    return `Message buffer must be at least ${MIN_MEMORY_MESSAGE_BUFFER_LIMIT}`;
+  }
+
+  if (value > MAX_MEMORY_MESSAGE_BUFFER_LIMIT) {
+    return `Browser limit is ${MAX_MEMORY_MESSAGE_BUFFER_LIMIT} buffered messages`;
+  }
+
+  return null;
+}

src/config/config.svelte.ts

@@ -1,4 +1,13 @@
-import { DEFAULT_MAX_USERS, validateMaxUsers, validateRelayUrl } from "./config-validator";
+import {
+  DEFAULT_MAX_USERS,
+  DEFAULT_STORAGE_BACKEND,
+  validateMaxUsers,
+  validateMessageBufferLimit,
+  validateRelayUrl,
+  validateStorageBackend,
+} from "./config-validator";
+import type { BrowserCoordinatorStorageBackend } from "../cordn/coordinator/storage/browserCoordinatorStorage";
+import { DEFAULT_MEMORY_MESSAGE_BUFFER_LIMIT } from "../cordn/coordinator/storage/inMemoryStorage";
 
 const CONFIG_STORAGE_KEY = "cordn:v1:config";
 const CONFIG_STORAGE_VERSION = 1;
@@ -15,13 +24,17 @@ export interface RelayConfig {
 export interface BrowserCoordinatorOptions {
   announce: boolean;
   maxUsers: number;
+  storageBackend: BrowserCoordinatorStorageBackend;
+  messageBufferLimit: number;
 }
 
 interface PersistedConfig {
   version: typeof CONFIG_STORAGE_VERSION;
   relays: Array<Pick<RelayConfig, "url" | "enabled">>;
   announce: boolean;
   maxUsers: number;
+  storageBackend?: BrowserCoordinatorStorageBackend;
+  messageBufferLimit?: number;
 }
 
 export class ConfigStore {
@@ -31,6 +44,8 @@ export class ConfigStore {
   limitError = $state<string | null>(null);
   announce = $state(false);
   maxUsers = $state(DEFAULT_MAX_USERS);
+  storageBackend = $state<BrowserCoordinatorStorageBackend>(DEFAULT_STORAGE_BACKEND);
+  messageBufferLimit = $state(DEFAULT_MEMORY_MESSAGE_BUFFER_LIMIT);
 
   constructor() {
     this.loadPersistedConfig();
@@ -44,6 +59,8 @@ export class ConfigStore {
     return {
       announce: this.announce,
       maxUsers: this.maxUsers,
+      storageBackend: this.storageBackend,
+      messageBufferLimit: this.messageBufferLimit,
     };
   }
 
@@ -112,6 +129,31 @@ export class ConfigStore {
     return true;
   }
 
+  setStorageBackend(value: string): boolean {
+    if (!validateStorageBackend(value)) {
+      this.limitError = "Storage backend must be memory or IndexedDB";
+      return false;
+    }
+
+    this.storageBackend = value;
+    this.limitError = null;
+    this.persistConfig();
+    return true;
+  }
+
+  setMessageBufferLimit(value: number): boolean {
+    const error = validateMessageBufferLimit(value);
+    if (error) {
+      this.limitError = error;
+      return false;
+    }
+
+    this.messageBufferLimit = value;
+    this.limitError = null;
+    this.persistConfig();
+    return true;
+  }
+
   resetToDefaults(): void {
     clearPersistedConfig();
     this.relays = cloneDefaultRelays();
@@ -120,6 +162,8 @@ export class ConfigStore {
     this.limitError = null;
     this.announce = false;
     this.maxUsers = DEFAULT_MAX_USERS;
+    this.storageBackend = DEFAULT_STORAGE_BACKEND;
+    this.messageBufferLimit = DEFAULT_MEMORY_MESSAGE_BUFFER_LIMIT;
   }
 
   private persistConfig(): void {
@@ -132,6 +176,8 @@ export class ConfigStore {
       relays: this.relays.map((relay) => ({ url: relay.url, enabled: relay.enabled })),
       announce: this.announce,
       maxUsers: this.maxUsers,
+      storageBackend: this.storageBackend,
+      messageBufferLimit: this.messageBufferLimit,
     };
     localStorage.setItem(CONFIG_STORAGE_KEY, JSON.stringify(config));
   }
@@ -149,6 +195,8 @@ export class ConfigStore {
     }));
     this.announce = persisted.announce;
     this.maxUsers = persisted.maxUsers;
+    this.storageBackend = persisted.storageBackend ?? DEFAULT_STORAGE_BACKEND;
+    this.messageBufferLimit = persisted.messageBufferLimit ?? DEFAULT_MEMORY_MESSAGE_BUFFER_LIMIT;
   }
 }
 
@@ -186,12 +234,24 @@ function readPersistedConfig(): PersistedConfig | null {
 
     const maxUsers = typeof parsed.maxUsers === "number" ? Math.trunc(parsed.maxUsers) : DEFAULT_MAX_USERS;
     const limitError = validateMaxUsers(maxUsers);
+    const storageBackend =
+      typeof parsed.storageBackend === "string" && validateStorageBackend(parsed.storageBackend)
+        ? parsed.storageBackend
+        : DEFAULT_STORAGE_BACKEND;
+    const messageBufferLimit =
+      typeof parsed.messageBufferLimit === "number"
+        ? Math.trunc(parsed.messageBufferLimit)
+        : DEFAULT_MEMORY_MESSAGE_BUFFER_LIMIT;
 
     return {
       version: CONFIG_STORAGE_VERSION,
       relays,
       announce: parsed.announce === true,
       maxUsers: limitError ? DEFAULT_MAX_USERS : maxUsers,
+      storageBackend,
+      messageBufferLimit: validateMessageBufferLimit(messageBufferLimit)
+        ? DEFAULT_MEMORY_MESSAGE_BUFFER_LIMIT
+        : messageBufferLimit,
     };
   } catch {
     return null;

src/coordinator/coordinator.svelte.ts

@@ -1,5 +1,5 @@
 import { configStore } from "../config/config.svelte";
-import { clearPersistedCoordinatorState } from "../cordn/coordinator/storage/browserSqliteStorage";
+import { clearPersistedCoordinatorState } from "../cordn/coordinator/storage/browserCoordinatorStorage";
 import { KeyManager } from "../crypto/key-manager";
 import { keyStorage, WrongPassphraseError } from "../crypto/key-storage";
 import { transportFactory, type RunningTransport } from "../lib/transport";
@@ -132,7 +132,6 @@ export class CoordinatorStore {
         keyManager.getSecretKeyBytes(),
         configStore.enabledRelayUrls,
         configStore.coordinatorOptions,
-        this.persistenceEnabled,
         {
           onStarted: ({ publicKeyHex, relayUrls }) => {
             this.addDebugLog(