e62b72b5be
1. GO_BACK warning & stuck screens
When a deep link or direct push put the user on /feed/[id],
/profile/[address], /compose, or /settings without any prior stack
entry, tapping the header chevron emitted:
"ERROR The action 'GO_BACK' was not handled by any navigator"
and did nothing — user was stuck.
New helper lib/utils.safeBack(fallback = '/(app)/chats') wraps
router.canGoBack() — when there's history it pops; otherwise it
replace-navigates to a sensible fallback (chats list by default,
'/' for auth screens so we land back at the onboarding).
Applied to every header chevron and back-from-detail flow:
app/(app)/chats/[id], app/(app)/compose, app/(app)/feed/[id]
(header + onDeleted), app/(app)/feed/tag/[tag],
app/(app)/profile/[address], app/(app)/new-contact (header + OK
button on request-sent alert), app/(app)/settings,
app/(auth)/create, app/(auth)/import.
2. Prevent self-contact-request
new-contact.tsx now compares the resolved address against
keyFile.pub_key at two points:
- right after resolveUsername + getIdentity in search() — before
the profile card even renders, so the user doesn't see the
"Send request" CTA for themselves.
- inside sendRequest() as a belt-and-braces guard in case the
check was somehow bypassed.
The search path shows an inline error ("That's you. You can't
send a contact request to yourself."); sendRequest falls back to
an Alert with the same meaning. Both compare case-insensitively
against the pubkey hex so mixed-case pastes work.
Technically the server would still accept a self-request (the
chain stores it under contact_in:<self>:<self>), but it's a dead-
end UX-wise — the user can't chat with themselves — so the client
blocks it preemptively instead of letting users pay the fee for
nothing.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
DChain Messenger — React Native Client
E2E-encrypted mobile/desktop messenger built on the DChain blockchain stack.
Stack: React Native · Expo · NativeWind (Tailwind) · TweetNaCl · Zustand
Quick Start
cd client-app
npm install
npx expo start # opens Expo Dev Tools
# Press 'i' for iOS simulator, 'a' for Android, 'w' for web
Requirements
- Node.js 18+
- Expo Go on your phone (for Expo tunnel), or iOS/Android emulator
- A running DChain node (see root README for
docker compose up --build -d)
Project Structure
client-app/
├── app/
│ ├── _layout.tsx # Root layout — loads keys, sets up nav
│ ├── index.tsx # Welcome / onboarding
│ ├── (auth)/
│ │ ├── create.tsx # Generate new Ed25519 + X25519 keys
│ │ ├── created.tsx # Key created — export reminder
│ │ └── import.tsx # Import existing key.json
│ └── (app)/
│ ├── _layout.tsx # Tab bar — Chats · Wallet · Settings
│ ├── chats/
│ │ ├── index.tsx # Chat list with contacts
│ │ └── [id].tsx # Individual chat with E2E encryption
│ ├── requests.tsx # Incoming contact requests
│ ├── new-contact.tsx # Add contact by @username or address
│ ├── wallet.tsx # Balance + TX history + send
│ └── settings.tsx # Node URL, key export, profile
├── components/ui/ # shadcn-style components (Button, Card, Input…)
├── hooks/
│ ├── useMessages.ts # Poll relay inbox, decrypt messages
│ ├── useBalance.ts # Poll token balance
│ └── useContacts.ts # Load contacts + poll contact requests
└── lib/
├── api.ts # REST client for all DChain endpoints
├── crypto.ts # NaCl box encrypt/decrypt, Ed25519 sign
├── storage.ts # SecureStore (keys) + AsyncStorage (data)
├── store.ts # Zustand global state
├── types.ts # TypeScript interfaces
└── utils.ts # cn(), formatAmount(), relativeTime()
Cryptography
| Operation | Algorithm | Library |
|---|---|---|
| Transaction signing | Ed25519 | TweetNaCl sign |
| Key exchange | X25519 (Curve25519) | TweetNaCl box |
| Message encryption | NaCl box (XSalsa20-Poly1305) | TweetNaCl box |
| Key storage | Device secure enclave | expo-secure-store |
Messages are encrypted as:
Envelope {
sender_pub: <X25519 hex> // sender's public key
recipient_pub: <X25519 hex> // recipient's public key
nonce: <24-byte hex> // random per message
ciphertext: <hex> // NaCl box(plaintext, nonce, sender_priv, recipient_pub)
}
Connect to your node
- Start the DChain node:
docker compose up --build -d - Open the app → Settings → Node URL →
http://YOUR_IP:8081 - If using Expo Go on physical device: your PC and phone must be on the same network, or use
npx expo start --tunnel
Key File Format
The key.json exported/imported by the app:
{
"pub_key": "26018d40...", // Ed25519 public key (64 hex chars)
"priv_key": "...", // Ed25519 private key (128 hex chars)
"x25519_pub": "...", // X25519 public key (64 hex chars)
"x25519_priv": "..." // X25519 private key (64 hex chars)
}
This is the same format as the Go node's --key flag.