neo-go/pkg/rpc/response/events.go
Roman Khimov e1408b6525 rpc/server: add notification subscription
Note that the protocol differs a bit from #895 in its notifications format,
to avoid additional server-side processing we're omitting some metadata like:
 * block size and confirmations
 * transaction fees, confirmations, block hash and timestamp
 * application execution doesn't have ScriptHash populated

Some block fields may also differ in encoding compared to `getblock` results
(like nonce field).

I think these differences are unnoticieable for most use cases, so we can
leave them as is, but it can be changed in the future.
2020-05-13 17:17:41 +03:00

79 lines
1.8 KiB
Go

package response
import (
"encoding/json"
"github.com/pkg/errors"
)
type (
// EventID represents an event type happening on the chain.
EventID byte
)
const (
// InvalidEventID is an invalid event id that is the default value of
// EventID. It's only used as an initial value similar to nil.
InvalidEventID EventID = iota
// BlockEventID is a `block_added` event.
BlockEventID
// TransactionEventID corresponds to `transaction_added` event.
TransactionEventID
// NotificationEventID represents `notification_from_execution` events.
NotificationEventID
// ExecutionEventID is used for `transaction_executed` events.
ExecutionEventID
)
// String is a good old Stringer implementation.
func (e EventID) String() string {
switch e {
case BlockEventID:
return "block_added"
case TransactionEventID:
return "transaction_added"
case NotificationEventID:
return "notification_from_execution"
case ExecutionEventID:
return "transaction_executed"
default:
return "unknown"
}
}
// GetEventIDFromString converts input string into an EventID if it's possible.
func GetEventIDFromString(s string) (EventID, error) {
switch s {
case "block_added":
return BlockEventID, nil
case "transaction_added":
return TransactionEventID, nil
case "notification_from_execution":
return NotificationEventID, nil
case "transaction_executed":
return ExecutionEventID, nil
default:
return 255, errors.New("invalid stream name")
}
}
// MarshalJSON implements json.Marshaler interface.
func (e EventID) MarshalJSON() ([]byte, error) {
return json.Marshal(e.String())
}
// UnmarshalJSON implements json.Unmarshaler interface.
func (e *EventID) UnmarshalJSON(b []byte) error {
var s string
err := json.Unmarshal(b, &s)
if err != nil {
return err
}
id, err := GetEventIDFromString(s)
if err != nil {
return err
}
*e = id
return nil
}