In this example we will update the authorized flag of an existing trustline. This can only be called by the issuer of a trustline’s asset, and only when AUTHORIZATION REQUIRED (at the minimum) has been set on the issuer’s account.
The issuer can only clear the authorized flag if the issuer has the AUTH_REVOCABLE_FLAG set. Otherwise, the issuer can only set the authorized flag.
If the issuer clears the authorized flag, all offers owned by the trustor that are either selling type or buying type will be deleted.
// Create two random key pairs, we will need them later for signing.
$issuerKeypair = KeyPair::random();
$trustorKeypair = KeyPair::random();
// Account Ids.
$issuerAccountId = $issuerKeypair->getAccountId();
$trustorAccountId = $trustorKeypair->getAccountId();
// Create trustor account.
FriendBot::fundTestAccount($trustorAccountId);
// Load the trustor account so that we can later create the trustline.
$trustorAccount = $sdk->requestAccount($trustorAccountId);
// Create the issuer account.
$cao = (new CreateAccountOperationBuilder($issuerAccountId, "10"))->build();
$transaction = (new TransactionBuilder($trustorAccount))->addOperation($cao)->build();
// Sign the transaction.
$transaction->sign($trustorKeypair, Network::testnet());
// Submit the transaction to stellar.
$sdk->submitTransaction($transaction);
// Load the issuer account.
$issuerAccount = $sdk->requestAccount($issuerAccountId);
// Set up the flags on the isser account.
$sopb = new SetOptionsOperationBuilder();
$sopb->setSetFlags(3); // Auth required, auth revocable
// Build the transaction.
$transaction = (new TransactionBuilder($issuerAccount))->addOperation($sopb->build())->build();
// Sign the transaction.
$transaction->sign($issuerKeypair, Network::testnet());
// Submit the transaction to stellar.
$sdk->submitTransaction($transaction);
// Reload the issuer account to check the flags.
$issuerAccount = $sdk->requestAccount($issuerAccountId);
if ($issuerAccount->getFlags()->isAuthRequired()
&& $issuerAccount->getFlags()->isAuthRevocable()
&& !$issuerAccount->getFlags()->isAuthImmutable()) {
print(PHP_EOL."issuer account flags correctly set");
}
// Define our custom asset.
$assetCode = "ASTRO";
$astroDollar = new AssetTypeCreditAlphaNum12($assetCode, $issuerAccountId);
// Build the trustline.
$limit = "10000";
// Build the operation.
$cto = (new ChangeTrustOperationBuilder($astroDollar, $limit))->build();
// Build the transaction.
$transaction = (new TransactionBuilder($trustorAccount))->addOperation($cto)->build();
// Sign the transaction.
$transaction->sign($trustorKeypair, Network::testnet());
// Submit the transaction to stellar.
$sdk->submitTransaction($transaction);
// Reload the trustor account to see if the trustline has been created.
$trustorAccount = $sdk->requestAccount($trustorAccountId);
foreach ($trustorAccount->getBalances() as $balance) {
if ($balance->getAssetCode() == $assetCode) {
print(PHP_EOL."trustline awailable");
break;
}
}
// Now lets try to send some custom asset funds to the trustor account.
// This should not work, because the issuer must authorize the trustline first.
$po = (new PaymentOperationBuilder($trustorAccountId, $astroDollar, "100"))->build();
$transaction = (new TransactionBuilder($issuerAccount))->addOperation($po)->build();
// Sign the transaction.
$transaction->sign($issuerKeypair, Network::testnet());
// Submit the transaction to stellar.
try {
$response = $sdk->submitTransaction($transaction);
} catch (HorizonRequestException $e) {
print(PHP_EOL."trustline is not authorized.");
}
// Now let's authorize the trustline.
// Build the allow trust operation. Set the authorized flag to 1.
$aop = (new AllowTrustOperationBuilder($trustorAccountId, $assetCode, 1, 0))->build(); // authorize
$transaction = (new TransactionBuilder($issuerAccount))->addOperation($aop)->build();
// Sign the transaction.
$transaction->sign($issuerKeypair, Network::testnet());
// Submit the transaction to stellar.
$response = $sdk->submitTransaction($transaction);
// Try again to send the payment. Should work now.
$po = (new PaymentOperationBuilder($trustorAccountId, $astroDollar, "100"))->build();
$transaction = (new TransactionBuilder($issuerAccount))->addOperation($po)->build();
// Sign the transaction.
$transaction->sign($issuerKeypair, Network::testnet());
// Submit the transaction to stellar.
$response = $sdk->submitTransaction($transaction);
if ($response->isSuccessful()) { // authorized.
print(PHP_EOL."success - trustline is now authorized.");
}
// Now create an offer, to see if it will be deleted after we will remove the authorized flag.
$amountSelling = "100";
$price = "0.5";
$cpso = (new CreatePassiveSellOfferOperationBuilder($astroDollar, Asset::native(), $amountSelling, Price::fromString($price)))->build();
$transaction = (new TransactionBuilder($trustorAccount))->addOperation($cpso)->build();
// Sign the transaction.
$transaction->sign($trustorKeypair, Network::testnet());
// Submit the transaction to stellar.
$response = $sdk->submitTransaction($transaction);
// Check if the offer has been added.
$offersPage = $sdk->offers()->forAccount($trustorAccountId)->execute();
$offer = $offersPage->getOffers()->toArray()[0];
if ($offer->getBuying() == Asset::native()
&& $offer->getSelling() == $astroDollar) {
print(PHP_EOL."offer found");
}
// Now lets remove the authorization. To do so, we set the authorized flag to 0.
// This should also delete the offer.
$aop = (new AllowTrustOperationBuilder($trustorAccountId, $assetCode, 0, 0))->build(); // not authorized
$transaction = (new TransactionBuilder($issuerAccount))->addOperation($aop)->build();
// Sign the transaction.
$transaction->sign($issuerKeypair, Network::testnet());
// Submit the transaction to stellar.
$sdk->submitTransaction($transaction);
// Check if the offer has been deleted.
$offersPage = $sdk->offers()->forAccount($trustorAccountId)->execute();
if ($offersPage->getOffers()->count() == 0) {
print(PHP_EOL."success, offer has been deleted");
}
// Now, let's authorize the trustline again and then authorize it only to maintain liabilities.
$aop = (new AllowTrustOperationBuilder($trustorAccountId, $assetCode, 1, 0))->build(); // authorize
$transaction = (new TransactionBuilder($issuerAccount))->addOperation($aop)->build();
// Sign the transaction.
$transaction->sign($issuerKeypair, Network::testnet());
// Submit the transaction to stellar.
$sdk->submitTransaction($transaction);
// Create the offer again.
$cpso = (new CreatePassiveSellOfferOperationBuilder($astroDollar, Asset::native(), $amountSelling, Price::fromString($price)))->build();
$transaction = (new TransactionBuilder($trustorAccount))->addOperation($cpso)->build();
// Sign the transaction.
$transaction->sign($trustorKeypair, Network::testnet());
// Submit the transaction to stellar.
$sdk->submitTransaction($transaction);
// Check that the offer has been created.
$offersPage = $sdk->offers()->forAccount($trustorAccountId)->execute();
if ($offersPage->getOffers()->count() == 1) {
print(PHP_EOL."offer has been created");
}
// Now let's deautorize the trustline but allow the trustor to maintain his offer.
// For this, we set the authorized flag to 2.
$aop = (new AllowTrustOperationBuilder($trustorAccountId, $assetCode, 0, 1))->build(); // authorized to maintain liabilities.
$transaction = (new TransactionBuilder($issuerAccount))->addOperation($aop)->build();
// Sign the transaction.
$transaction->sign($issuerKeypair, Network::testnet());
// Submit the transaction to stellar.
$sdk->submitTransaction($transaction);
// Load the offers to see if our offer is still there.
// Check that the offer has been created.
$offersPage = $sdk->offers()->forAccount($trustorAccountId)->execute();
if ($offersPage->getOffers()->count() == 1) {
print(PHP_EOL."offer exists");
}
// Next, let's try to send some ASTRO to the trustor account.
// This should not work, since the trustline has been deauthorized before.
$po = (new PaymentOperationBuilder($trustorAccountId, $astroDollar, "100"))->build();
$transaction = (new TransactionBuilder($issuerAccount))->addOperation($po)->build();
// Sign the transaction.
$transaction->sign($issuerKeypair, Network::testnet());
try {
// Submit the transaction to stellar.
$sdk->submitTransaction($transaction);
} catch (HorizonRequestException $e) {
print(PHP_EOL."payment correctly blocked.");
}