92 lines
2.9 KiB
Go
92 lines
2.9 KiB
Go
// Copyright 2019 The go-ethereum Authors
|
|
// This file is part of the go-ethereum library.
|
|
//
|
|
// The go-ethereum library is free software: you can redistribute it and/or modify
|
|
// it under the terms of the GNU Lesser General Public License as published by
|
|
// the Free Software Foundation, either version 3 of the License, or
|
|
// (at your option) any later version.
|
|
//
|
|
// The go-ethereum library is distributed in the hope that it will be useful,
|
|
// but WITHOUT ANY WARRANTY; without even the implied warranty of
|
|
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
|
|
// GNU Lesser General Public License for more details.
|
|
//
|
|
// You should have received a copy of the GNU Lesser General Public License
|
|
// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
|
|
|
|
package statediff
|
|
|
|
import (
|
|
"context"
|
|
"sync"
|
|
"time"
|
|
|
|
"github.com/ethereum/go-ethereum/log"
|
|
"github.com/ethereum/go-ethereum/rpc"
|
|
)
|
|
|
|
// APIName is the namespace used for the state diffing service API
|
|
const APIName = "statediff"
|
|
|
|
// APIVersion is the version of the state diffing service API
|
|
const APIVersion = "0.0.1"
|
|
|
|
// PublicStateDiffAPI provides the a websocket service
|
|
// that can be used to stream out state diffs as they
|
|
// are produced by a full node
|
|
type PublicStateDiffAPI struct {
|
|
sds IService
|
|
|
|
mu sync.Mutex
|
|
lastUsed map[string]time.Time // keeps track when a filter was polled for the last time.
|
|
}
|
|
|
|
// NewPublicStateDiffAPI create a new state diff websocket streaming service.
|
|
func NewPublicStateDiffAPI(sds IService) *PublicStateDiffAPI {
|
|
return &PublicStateDiffAPI{
|
|
sds: sds,
|
|
lastUsed: make(map[string]time.Time),
|
|
mu: sync.Mutex{},
|
|
}
|
|
}
|
|
|
|
// Subscribe is the public method to setup a subscription that fires off state-diff payloads as they are created
|
|
func (api *PublicStateDiffAPI) Subscribe(ctx context.Context) (*rpc.Subscription, error) {
|
|
// ensure that the RPC connection supports subscriptions
|
|
notifier, supported := rpc.NotifierFromContext(ctx)
|
|
if !supported {
|
|
return nil, rpc.ErrNotificationsUnsupported
|
|
}
|
|
|
|
// create subscription and start waiting for statediff events
|
|
rpcSub := notifier.CreateSubscription()
|
|
|
|
go func() {
|
|
// subscribe to events from the state diff service
|
|
payloadChannel := make(chan Payload)
|
|
quitChan := make(chan bool)
|
|
api.sds.Subscribe(rpcSub.ID, payloadChannel, quitChan)
|
|
|
|
// loop and await state diff payloads and relay them to the subscriber with then notifier
|
|
for {
|
|
select {
|
|
case packet := <-payloadChannel:
|
|
if err := notifier.Notify(rpcSub.ID, packet); err != nil {
|
|
log.Error("Failed to send state diff packet", "err", err)
|
|
}
|
|
case <-rpcSub.Err():
|
|
err := api.sds.Unsubscribe(rpcSub.ID)
|
|
if err != nil {
|
|
log.Error("Failed to unsubscribe from the state diff service", err)
|
|
}
|
|
return
|
|
case <-quitChan:
|
|
// don't need to unsubscribe, statediff service does so before sending the quit signal
|
|
return
|
|
}
|
|
}
|
|
}()
|
|
|
|
return rpcSub, nil
|
|
}
|