This section describes the API offered by the Taler wire gateway. The API is used by the exchange to trigger transactions and query incoming transactions, as well as by the auditor to query incoming and outgoing transactions.
This API is currently implemented by the Taler Demo Bank, as well as by LibEuFin (work in progress).
The bank library authenticates requests to the wire gateway via HTTP basic auth.
POST ${BASE_URL}/transfer¶This API allows the exchange to make a transaction, typically to a merchant. The bank account of the exchange is not included in the request, but instead derived from the user name in the authentication header and/or the request base URL.
To make the API idempotent, the client must include a nonce. Requests with the same nonce are rejected unless the request is the same.
Request: The body of this request must have the format of a TransferRequest.
Response:
transaction_uid but different transaction details
has been submitted before.Details:
interface TransferResponse {
// Timestamp that indicates when the wire transfer will be executed.
// In cases where the wire transfer gateway is unable to know when
// the wire transfer will be executed, the time at which the request
// has been received and stored will be returned.
// The purpose of this field is for debugging (humans trying to find
// the transaction) as well as for taxation (determining which
// time period a transaction belongs to).
timestamp: Timestamp;
// Opaque ID of the transaction that the bank has made.
row_id: SafeUint64;
}
interface TransferRequest {
// Nonce to make the request idempotent. Requests with the same
// transaction_uid that differ in any of the other fields
// are rejected.
request_uid: HashCode;
// Amount to transfer.
amount: Amount;
// Base URL of the exchange. Shall be included by the bank gateway
// in the appropriate section of the wire transfer details.
exchange_base_url: string;
// Wire transfer identifier chosen by the exchange,
// used by the merchant to identify the Taler order(s)
// associated with this wire transfer.
wtid: ShortHashCode;
// The recipient's account identifier as a payto URI.
credit_account: string;
}
GET ${BASE_URL}/history/incoming¶Return a list of transactions made from or to the exchange.
Incoming transactions must contain a valid reserve public key. If a bank transaction does not conform to the right syntax, the wire gateway must not report it to the exchange, and send funds back to the sender if possible.
The bank account of the exchange is determined via the base URL and/or the
user name in the Authorization header. In fact the transaction history
might come from a “virtual” account, where multiple real bank accounts are
merged into one history.
Transactions are identified by an opaque numeric identifier, referred to here as row ID. The semantics of the row ID (including its sorting order) are determined by the bank server and completely opaque to the client.
The list of returned transactions is determined by a row ID starting point and a signed non-zero integer delta:
If starting point is not explicitly given, it defaults to:
Request:
long_poll_ms
milliseconds for new transactions that match the query to arrive and only
then send the HTTP response. A client must never rely on this behavior, as
the bank may return a response immediately or after waiting only a fraction
of long_poll_ms.Response:
interface IncomingHistory {
// Array of incoming transactions.
incoming_transactions : IncomingBankTransaction[];
}
// Union discriminated by the "type" field.
type IncomingBankTransaction =
| IncomingReserveTransaction
| IncomingWadTransaction;
interface IncomingReserveTransaction {
type: "RESERVE";
// Opaque identifier of the returned record.
row_id: SafeUint64;
// Date of the transaction.
date: Timestamp;
// Amount transferred.
amount: Amount;
// Payto URI to identify the receiver of funds.
// This must be one of the exchange's bank accounts.
credit_account: string;
// Payto URI to identify the sender of funds.
debit_account: string;
// The reserve public key extracted from the transaction details.
reserve_pub: EddsaPublicKey;
}
interface IncomingWadTransaction {
type: "WAD";
// Opaque identifier of the returned record.
row_id: SafeUint64;
// Date of the transaction.
date: Timestamp;
// Amount transferred.
amount: Amount;
// Payto URI to identify the receiver of funds.
// This must be one of the exchange's bank accounts.
credit_account: string;
// Payto URI to identify the sender of funds.
debit_account: string;
// Base URL of the exchange that originated the wad.
origin_exchange_url: string;
// The reserve public key extracted from the transaction details.
wad_id: WadId;
}
GET ${BASE_URL}/history/outgoing¶Return a list of transactions made by the exchange, typically to a merchant.
The bank account of the exchange is determined via the base URL and/or the
user name in the Authorization header. In fact the transaction history
might come from a “virtual” account, where multiple real bank accounts are
merged into one history.
Transactions are identified by an opaque integer, referred to here as row ID. The semantics of the row ID (including its sorting order) are determined by the bank server and completely opaque to the client.
The list of returned transactions is determined by a row ID starting point and a signed non-zero integer delta:
If starting point is not explicitly given, it defaults to:
Request:
long_poll_ms
milliseconds for new transactions that match the query to arrive and only
then send the HTTP response. A client must never rely on this behavior, as
the bank may return a response immediately or after waiting only a fraction
of long_poll_ms.Response:
interface OutgoingHistory {
// Array of outgoing transactions.
outgoing_transactions : OutgoingBankTransaction[];
}
interface OutgoingBankTransaction {
// Opaque identifier of the returned record.
row_id: SafeUint64;
// Date of the transaction.
date: Timestamp;
// Amount transferred.
amount: Amount;
// Payto URI to identify the receiver of funds.
credit_account: string;
// Payto URI to identify the sender of funds.
// This must be one of the exchange's bank accounts.
debit_account: string;
// The wire transfer ID in the outgoing transaction.
wtid: ShortHashCode;
// Base URL of the exchange.
exchange_base_url: string;
}
Endpoints in this section are only used for integration tests and never exposed by bank gateways in production.
POST ${BASE_URL}/admin/add-incoming¶Simulate a transfer from a customer to the exchange. This API is not idempotent since it’s only used in testing.
Request: The body of this request must have the format of a AddIncomingRequest.
Response:
interface AddIncomingRequest {
// Amount to transfer.
amount: Amount;
// Reserve public key that is included in the wire transfer details
// to identify the reserve that is being topped up.
reserve_pub: EddsaPublicKey;
// Account (as payto URI) that makes the wire transfer to the exchange.
// Usually this account must be created by the test harness before this API is
// used. An exception is the "exchange-fakebank", where any debit account can be
// specified, as it is automatically created.
debit_account: string;
}
interface AddIncomingResponse {
// Timestamp that indicates when the wire transfer will be executed.
// In cases where the wire transfer gateway is unable to know when
// the wire transfer will be executed, the time at which the request
// has been received and stored will be returned.
// The purpose of this field is for debugging (humans trying to find
// the transaction) as well as for taxation (determining which
// time period a transaction belongs to).
timestamp: Timestamp;
// Opaque ID of the transaction that the bank has made.
row_id: SafeUint64;
}