Custom RPC Method Bindings

Custom RPC method bindings can be created by implementing the w3types.RPCCaller interface. By convention, the w3types.RPCCaller is setup using an unexported factory, which implements the w3types.RPCCallerFactory interface, to keep the package API small and readable. The factory stores the method parameters and the reference to the return value.

Example: RPC binding for the Otterscan ots_getTransactionBySenderAndNonce method (Playground)

// TxBySenderAndNonceFactory requests the senders transaction hash by the nonce.
func TxBySenderAndNonceFactory(sender common.Address, nonce uint64) w3types.RPCCallerFactory[common.Hash] {
    return &getTransactionBySenderAndNonceFactory{
        sender: sender,
        nonce:  nonce,
    }
}
 
// getTransactionBySenderAndNonceFactory implements the w3types.RPCCaller and
// w3types.RPCCallerFactory interfaces. It stores the method parameters and
// the reference to the return value.
type getTransactionBySenderAndNonceFactory struct {
    // params
    sender common.Address
    nonce  uint64
 
    // returns
    returns *common.Hash
}
 
// Returns sets the reference to the return value.
func (f *getTransactionBySenderAndNonceFactory) Returns(txHash *common.Hash) w3types.RPCCaller {
    f.returns = txHash
    return f
}
 
// CreateRequest creates a batch request element for the Otterscan getTransactionBySenderAndNonce method.
func (f *getTransactionBySenderAndNonceFactory) CreateRequest() (rpc.BatchElem, error) {
    return rpc.BatchElem{
        Method: "ots_getTransactionBySenderAndNonce",
        Args:   []any{f.sender, f.nonce},
        Result: f.returns,
    }, nil
}
 
// HandleResponse handles the response of the Otterscan getTransactionBySenderAndNonce method.
func (f *getTransactionBySenderAndNonceFactory) HandleResponse(elem rpc.BatchElem) error {
    if err := elem.Error; err != nil {
        return err
    }
    return nil
}
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