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Smartdevs17 merged 2 commits into from
Mar 30, 2026
Merged

docs(api): align examples with client-side signing flow #155

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docs(api): align examples with client-side signing flow
OperaCode Mar 28, 2026
951db58
Merge branch 'main' into fix/issue-88-validation
OperaCode Mar 28, 2026
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39 changes: 19 additions & 20 deletions api/README.md
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -4,7 +4,8 @@ REST API for StellarLend core lending operations (deposit, borrow, repay, withdr

## Features

- REST endpoints for deposit, borrow, repay, withdraw operations
- Unsigned transaction preparation for deposit, borrow, repay, withdraw operations
- Signed transaction submission endpoint
- Request validation and error handling
- Transaction submission and monitoring
- Rate limiting and security middleware
Expand Down Expand Up @@ -38,48 +39,46 @@ JWT_SECRET=<your_secret_key>
### Health Check
`GET /api/health` - Check service status

### Deposit Collateral
`POST /api/lending/deposit`
### Prepare Transaction
`GET /api/lending/prepare/:operation`
```json
{
"userAddress": "G...",
"amount": "10000000",
"userSecret": "S..."
"amount": "10000000"
}
```

### Borrow Assets
`POST /api/lending/borrow`
Response:
```json
{
"userAddress": "G...",
"amount": "5000000",
"userSecret": "S..."
"unsignedXdr": "AAAA...",
"operation": "deposit",
"expiresAt": "2026-03-28T12:34:56.000Z"
}
```

### Repay Debt
`POST /api/lending/repay`
### Submit Signed Transaction
`POST /api/lending/submit`
```json
{
"userAddress": "G...",
"amount": "5500000",
"userSecret": "S..."
"signedXdr": "AAAA..."
}
```

### Withdraw Collateral
`POST /api/lending/withdraw`
Response:
```json
{
"userAddress": "G...",
"amount": "2000000",
"userSecret": "S..."
"success": true,
"transactionHash": "abc123...",
"status": "success",
"ledger": 12345
}
```

All amounts in stroops (1 XLM = 10,000,000 stroops)

Clients must sign the returned XDR locally. The API does not accept Stellar secret keys.

## Testing

```bash
Expand Down
213 changes: 69 additions & 144 deletions api/examples/usage.ts
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Open in desktop
Original file line number Diff line number Diff line change
@@ -1,6 +1,6 @@
/**
* StellarLend API Usage Examples
*
*
* This file demonstrates how to interact with the StellarLend API
* for common lending operations.
*/
Expand All @@ -9,6 +9,14 @@ import axios, { AxiosError } from 'axios';

const API_BASE_URL = process.env.API_BASE_URL || 'http://localhost:3000/api';

type LendingOperation = 'deposit' | 'borrow' | 'repay' | 'withdraw';

interface PrepareResponse {
unsignedXdr: string;
operation: LendingOperation;
expiresAt: string;
}

interface TransactionResponse {
success: boolean;
transactionHash?: string;
Expand Down Expand Up @@ -37,149 +45,67 @@ async function checkHealth(): Promise<void> {
}

/**
* Deposit collateral into the lending protocol
* Request an unsigned XDR from the API
*/
async function depositCollateral(
async function prepareTransaction(
operation: LendingOperation,
userAddress: string,
amount: string,
userSecret: string,
assetAddress?: string
): Promise<TransactionResponse> {
): Promise<PrepareResponse> {
try {
console.log(`\n📥 Depositing ${amount} stroops...`);

const response = await axios.post<TransactionResponse>(
`${API_BASE_URL}/lending/deposit`,
{
userAddress,
assetAddress,
amount,
userSecret,
}
);

if (response.data.success) {
console.log('✅ Deposit successful!');
console.log(` Transaction Hash: ${response.data.transactionHash}`);
console.log(` Ledger: ${response.data.ledger}`);
} else {
console.log('❌ Deposit failed:', response.data.error);
}

return response.data;
} catch (error) {
handleError('Deposit', error);
throw error;
}
}
console.log(`\n📝 Preparing ${operation} transaction for ${amount} stroops...`);

/**
* Borrow assets against deposited collateral
*/
async function borrowAssets(
userAddress: string,
amount: string,
userSecret: string,
assetAddress?: string
): Promise<TransactionResponse> {
try {
console.log(`\n💰 Borrowing ${amount} stroops...`);

const response = await axios.post<TransactionResponse>(
`${API_BASE_URL}/lending/borrow`,
const response = await axios.get<PrepareResponse>(
`${API_BASE_URL}/lending/prepare/${operation}`,
{
userAddress,
assetAddress,
amount,
userSecret,
params: {
userAddress,
assetAddress,
amount,
},
}
);

if (response.data.success) {
console.log('✅ Borrow successful!');
console.log(` Transaction Hash: ${response.data.transactionHash}`);
console.log(` Ledger: ${response.data.ledger}`);
} else {
console.log('❌ Borrow failed:', response.data.error);
}
console.log('✅ Unsigned transaction prepared');
console.log(` Operation: ${response.data.operation}`);
console.log(` Expires At: ${response.data.expiresAt}`);
console.log(` XDR Preview: ${response.data.unsignedXdr.slice(0, 20)}...`);

return response.data;
} catch (error) {
handleError('Borrow', error);
handleError(`Prepare ${operation}`, error);
throw error;
}
}

/**
* Repay borrowed assets with interest
* Submit a client-signed XDR back to the API
*/
async function repayDebt(
userAddress: string,
amount: string,
userSecret: string,
assetAddress?: string
async function submitSignedTransaction(
signedXdr: string
): Promise<TransactionResponse> {
try {
console.log(`\n💳 Repaying ${amount} stroops...`);

const response = await axios.post<TransactionResponse>(
`${API_BASE_URL}/lending/repay`,
{
userAddress,
assetAddress,
amount,
userSecret,
}
);
console.log('\n🚀 Submitting signed transaction...');

if (response.data.success) {
console.log('✅ Repayment successful!');
console.log(` Transaction Hash: ${response.data.transactionHash}`);
console.log(` Ledger: ${response.data.ledger}`);
} else {
console.log('❌ Repayment failed:', response.data.error);
}

return response.data;
} catch (error) {
handleError('Repay', error);
throw error;
}
}

/**
* Withdraw collateral from the protocol
*/
async function withdrawCollateral(
userAddress: string,
amount: string,
userSecret: string,
assetAddress?: string
): Promise<TransactionResponse> {
try {
console.log(`\n📤 Withdrawing ${amount} stroops...`);

const response = await axios.post<TransactionResponse>(
`${API_BASE_URL}/lending/withdraw`,
`${API_BASE_URL}/lending/submit`,
{
userAddress,
assetAddress,
amount,
userSecret,
signedXdr,
}
);

if (response.data.success) {
console.log('✅ Withdrawal successful!');
console.log('✅ Transaction successful!');
console.log(` Transaction Hash: ${response.data.transactionHash}`);
console.log(` Ledger: ${response.data.ledger}`);
} else {
console.log('❌ Withdrawal failed:', response.data.error);
console.log('❌ Transaction failed:', response.data.error);
}

return response.data;
} catch (error) {
handleError('Withdraw', error);
handleError('Submit', error);
throw error;
}
}
Expand All @@ -203,6 +129,16 @@ function handleError(operation: string, error: unknown): void {
}
}

/**
* Placeholder signing hook for local wallet integration.
* Replace this with Freighter, WalletKit, or another signer in real usage.
*/
async function signTransactionLocally(unsignedXdr: string): Promise<string> {
console.log('\n🔐 Sign the XDR locally in your wallet before submitting it');
console.log(` Unsigned XDR: ${unsignedXdr}`);
throw new Error('Implement local signing before using this example');
}

/**
* Complete lending lifecycle example
*/
Expand All @@ -211,34 +147,27 @@ async function completeLendingCycle(): Promise<void> {
console.log('StellarLend API - Complete Lending Cycle Example');
console.log('='.repeat(60));

// Replace with your actual testnet credentials
// Replace with your actual testnet public address
const USER_ADDRESS = 'GXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX';
const USER_SECRET = 'SXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX';

const OPERATIONS: Array<{ operation: LendingOperation; amount: string }> = [
{ operation: 'deposit', amount: '100000000' },
{ operation: 'borrow', amount: '50000000' },
{ operation: 'repay', amount: '55000000' },
{ operation: 'withdraw', amount: '50000000' },
];

try {
// 1. Check health
await checkHealth();

// 2. Deposit collateral (10 XLM)
await depositCollateral(USER_ADDRESS, '100000000', USER_SECRET);

// Wait a bit for transaction to settle
await new Promise(resolve => setTimeout(resolve, 5000));

// 3. Borrow assets (5 XLM)
await borrowAssets(USER_ADDRESS, '50000000', USER_SECRET);
for (const { operation, amount } of OPERATIONS) {
const prepared = await prepareTransaction(operation, USER_ADDRESS, amount);
const signedXdr = await signTransactionLocally(prepared.unsignedXdr);
await submitSignedTransaction(signedXdr);

// Wait a bit for transaction to settle
await new Promise(resolve => setTimeout(resolve, 5000));

// 4. Repay debt (5.5 XLM with interest)
await repayDebt(USER_ADDRESS, '55000000', USER_SECRET);

// Wait a bit for transaction to settle
await new Promise(resolve => setTimeout(resolve, 5000));

// 5. Withdraw collateral (5 XLM)
await withdrawCollateral(USER_ADDRESS, '50000000', USER_SECRET);
// Wait a bit for transaction to settle before the next step
await new Promise((resolve) => setTimeout(resolve, 5000));
}

console.log('\n' + '='.repeat(60));
console.log('✅ Complete lending cycle finished successfully!');
Expand All @@ -259,31 +188,28 @@ async function errorHandlingExamples(): Promise<void> {
console.log('='.repeat(60));

const USER_ADDRESS = 'GXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX';
const USER_SECRET = 'SXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX';

// Example 1: Invalid amount (zero)
try {
console.log('\n1. Testing zero amount (should fail)...');
await depositCollateral(USER_ADDRESS, '0', USER_SECRET);
await prepareTransaction('deposit', USER_ADDRESS, '0');
} catch (error) {
console.log(' Expected error caught ✓');
}

// Example 2: Invalid address
try {
console.log('\n2. Testing invalid address (should fail)...');
await depositCollateral('invalid_address', '1000000', USER_SECRET);
await prepareTransaction('deposit', 'invalid_address', '1000000');
} catch (error) {
console.log(' Expected error caught ✓');
}

// Example 3: Missing required field
// Example 3: Missing signed XDR
try {
console.log('\n3. Testing missing secret (should fail)...');
await axios.post(`${API_BASE_URL}/lending/deposit`, {
userAddress: USER_ADDRESS,
amount: '1000000',
// userSecret missing
console.log('\n3. Testing missing signed XDR (should fail)...');
await axios.post(`${API_BASE_URL}/lending/submit`, {
// signedXdr missing
});
} catch (error) {
console.log(' Expected error caught ✓');
Expand Down Expand Up @@ -312,10 +238,9 @@ if (require.main === module) {

export {
checkHealth,
depositCollateral,
borrowAssets,
repayDebt,
withdrawCollateral,
prepareTransaction,
submitSignedTransaction,
signTransactionLocally,
completeLendingCycle,
errorHandlingExamples,
};
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