Hyperledger Fabric SDK for Node.js

Interface: Contract

fabric-network. Contract

Represents a smart contract (chaincode) instance in a network. Applications should get a Contract instance using the networks's getContract method.

The Contract allows applications to:

  • Submit transactions that store state to the ledger using submitTransaction.
  • Evaluate transactions that query state from the ledger using evaluateTransaction.
  • Listen for new chaincode events and replay previous chaincode events emitted by the smart contract using addContractListener.

If more control over transaction invocation is required, such as including transient data, createTransaction can be used to build a transaction request that is submitted to or evaluated by the smart contract.

Methods

addContractListener(listener [, options])

Add a listener to receive all chaincode events emitted by the smart contract as part of successfully committed transactions. The default is to listen for full contract events from the current block position.
Parameters:
Name Type Argument Description
listener module:fabric-network.ContractListener A contract listener callback function.
options module:fabric-network.ListenerOptions <optional>
 Listener options.
Returns:
The added listener.
Type
Promise.<module:fabric-network.ContractListener>
Example
const listener: ContractListener = async (event) => {
    if (event.eventName === 'newOrder') {
        const details = event.payload.toString('utf8');
        // Run business process to handle orders
    }
};
contract.addContractListener(listener);

addDiscoveryInterest(interest)

Provide a Discovery Interest settings to help the peer's discovery service build an endorsement plan. This chaincode Id will be include by default in the list of discovery interests. If this contract's chaincode is in one or more collections then use this method with this chaincode Id to change the default discovery interest to include those collection names.
Parameters:
Name Type Description
interest DiscoveryInterest These will be added to the existing discovery interests and used when module:fabric-network.Transaction#submit is called.
Returns:
This Contract instance
Type
Contract

createTransaction(name)

Create an object representing a specific invocation of a transaction function implemented by this contract, and provides more control over the transaction invocation. A new transaction object must be created for each transaction invocation.
Parameters:
Name Type Description
name string Transaction function name.
Returns:
A transaction object.
Type
module:fabric-network.Transaction

deserializeTransaction(data)

Deserialize a transaction from previously saved state.
Parameters:
Name Type Description
data Buffer Serialized transaction data.
Returns:
A transaction object.
Type
module:fabric-network.Transaction

evaluateTransaction(name [, args])

Evaluate a transaction function and return its results. The transaction function name will be evaluated on the endorsing peers but the responses will not be sent to the ordering service and hence will not be committed to the ledger. This is used for querying the world state. This function is equivalent to calling createTransaction(name).evaluate().
Parameters:
Name Type Argument Description
name string Transaction function name.
args string <optional>
<repeatable>
 Transaction function arguments.
Returns:
Payload response from the transaction function.
Type
Buffer

getDiscoveryInterests()

Retrieve the Discovery Interest settings that will help the peer's discovery service build an endorsement plan.
Returns:
- An array of DiscoveryInterest
Type
Array.<DiscoveryInterest>

removeContractListener(listener)

Remove a previously added contract listener.
Parameters:
Name Type Description
listener module:fabric-network.ContractListener A contract listener callback function.

resetDiscoveryInterests()

reset Discovery interest to default of this contracts chaincode name and no collection names and no other chaincode names.
Returns:
This Contract instance
Type
Contract

submitTransaction(name [, args])

Submit a transaction to the ledger. The transaction function name will be evaluated on the endorsing peers and then submitted to the ordering service for committing to the ledger. This function is equivalent to calling createTransaction(name).submit().
Parameters:
Name Type Argument Description
name string Transaction function name.
args string <optional>
<repeatable>
 Transaction function arguments.
Throws:
If the transaction was successfully submitted to the orderer but timed out before a commit event was received from peers.
Type
module:fabric-network.TimeoutError
Returns:
Payload response from the transaction function.
Type
Buffer