ipld-eth-server/pkg/eth/client/rpc_client.go
2019-10-28 12:30:24 +01:00

92 lines
2.9 KiB
Go

// VulcanizeDB
// Copyright © 2019 Vulcanize
// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU Affero General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
// This program 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 Affero General Public License for more details.
// You should have received a copy of the GNU Affero General Public License
// along with this program. If not, see <http://www.gnu.org/licenses/>.
package client
import (
"context"
"errors"
"reflect"
"github.com/ethereum/go-ethereum/rpc"
)
type RpcClient struct {
client *rpc.Client
ipcPath string
}
type BatchElem struct {
Method string
Args []interface{}
Result interface{}
Error error
}
func NewRpcClient(client *rpc.Client, ipcPath string) RpcClient {
return RpcClient{
client: client,
ipcPath: ipcPath,
}
}
func (client RpcClient) CallContext(ctx context.Context, result interface{}, method string, args ...interface{}) error {
//If an empty interface (or other nil object) is passed to CallContext, when the JSONRPC message is created the params will
//be interpreted as [null]. This seems to work fine for most of the ethereum clients (which presumably ignore a null parameter.
//Ganache however does not ignore it, and throws an 'Incorrect number of arguments' error.
if args == nil {
return client.client.CallContext(ctx, result, method)
} else {
return client.client.CallContext(ctx, result, method, args...)
}
}
func (client RpcClient) IpcPath() string {
return client.ipcPath
}
func (client RpcClient) SupportedModules() (map[string]string, error) {
return client.client.SupportedModules()
}
func (client RpcClient) BatchCall(batch []BatchElem) error {
var rpcBatch []rpc.BatchElem
for _, batchElem := range batch {
var newBatchElem = rpc.BatchElem{
Result: batchElem.Result,
Method: batchElem.Method,
Args: batchElem.Args,
Error: batchElem.Error,
}
rpcBatch = append(rpcBatch, newBatchElem)
}
return client.client.BatchCall(rpcBatch)
}
// Subscribe subscribes to an rpc "namespace_subscribe" subscription with the given channel
// The first argument needs to be the method we wish to invoke
func (client RpcClient) Subscribe(namespace string, payloadChan interface{}, args ...interface{}) (*rpc.ClientSubscription, error) {
chanVal := reflect.ValueOf(payloadChan)
if chanVal.Kind() != reflect.Chan || chanVal.Type().ChanDir()&reflect.SendDir == 0 {
return nil, errors.New("second argument to Subscribe must be a writable channel")
}
if chanVal.IsNil() {
return nil, errors.New("channel given to Subscribe must not be nil")
}
return client.client.Subscribe(context.Background(), namespace, payloadChan, args...)
}