90 lines
2.8 KiB
Go
90 lines
2.8 KiB
Go
// VulcanizeDB
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// Copyright © 2019 Vulcanize
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// This program is free software: you can redistribute it and/or modify
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// it under the terms of the GNU Affero General Public License as published by
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// the Free Software Foundation, either version 3 of the License, or
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// (at your option) any later version.
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// This program is distributed in the hope that it will be useful,
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// but WITHOUT ANY WARRANTY; without even the implied warranty of
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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// GNU Affero General Public License for more details.
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// You should have received a copy of the GNU Affero General Public License
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// along with this program. If not, see <http://www.gnu.org/licenses/>.
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package serve
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import (
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"context"
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"github.com/ethereum/go-ethereum/rpc"
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"github.com/ethereum/go-ethereum/statediff/indexer/shared"
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log "github.com/sirupsen/logrus"
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"github.com/vulcanize/ipld-eth-server/pkg/eth"
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)
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// APIName is the namespace used for the state diffing service API
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const APIName = "vdb"
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// APIVersion is the version of the state diffing service API
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const APIVersion = "0.0.1"
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// PublicServerAPI is the public api for the watcher
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type PublicServerAPI struct {
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w Server
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}
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// NewPublicServerAPI creates a new PublicServerAPI with the provided underlying Server process
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func NewPublicServerAPI(w Server) *PublicServerAPI {
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return &PublicServerAPI{
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w: w,
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}
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}
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// Stream is the public method to setup a subscription that fires off IPLD payloads as they are processed
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func (api *PublicServerAPI) Stream(ctx context.Context, params eth.SubscriptionSettings) (*rpc.Subscription, error) {
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// ensure that the RPC connection supports subscriptions
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notifier, supported := rpc.NotifierFromContext(ctx)
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if !supported {
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return nil, rpc.ErrNotificationsUnsupported
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}
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// create subscription and start waiting for stream events
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rpcSub := notifier.CreateSubscription()
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go func() {
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// subscribe to events from the SyncPublishScreenAndServe service
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payloadChannel := make(chan SubscriptionPayload, PayloadChanBufferSize)
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quitChan := make(chan bool, 1)
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go api.w.Subscribe(rpcSub.ID, payloadChannel, quitChan, params)
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// loop and await payloads and relay them to the subscriber using notifier
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for {
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select {
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case packet := <-payloadChannel:
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if err := notifier.Notify(rpcSub.ID, packet); err != nil {
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log.Error("Failed to send watcher data packet", "err", err)
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api.w.Unsubscribe(rpcSub.ID)
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return
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}
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case <-rpcSub.Err():
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api.w.Unsubscribe(rpcSub.ID)
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return
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case <-quitChan:
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// don't need to unsubscribe from the watcher, the service does so before sending the quit signal this way
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return
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}
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}
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}()
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return rpcSub, nil
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}
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// Chain returns the chain type that this watcher instance supports
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func (api *PublicServerAPI) Chain() shared.ChainType {
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return shared.Ethereum
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}
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