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rpc: add new client, use it everywhere

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The new client implementation supports concurrent requests,
subscriptions and replaces the various ad hoc RPC clients
throughout go-ethereum.
This commit is contained in:
Felix Lange
2016-07-12 17:47:15 +02:00
parent bb01bea4e2
commit 91b7690428
30 changed files with 2007 additions and 756 deletions
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160
accounts/abi/bind/backends/remote.go
View File

@ -17,11 +17,7 @@
package backends
import (
"encoding/json"
"fmt"
"math/big"
"sync"
"sync/atomic"
"github.com/ethereum/go-ethereum/accounts/abi/bind"
"github.com/ethereum/go-ethereum/common"
@ -37,119 +33,34 @@ var _ bind.ContractBackend = (*rpcBackend)(nil)
// rpcBackend implements bind.ContractBackend, and acts as the data provider to
// Ethereum contracts bound to Go structs. It uses an RPC connection to delegate
// all its functionality.
//
// Note: The current implementation is a blocking one. This should be replaced
// by a proper async version when a real RPC client is created.
type rpcBackend struct {
client rpc.Client // RPC client connection to interact with an API server
autoid uint32 // ID number to use for the next API request
lock sync.Mutex // Singleton access until we get to request multiplexing
client *rpc.Client // RPC client connection to interact with an API server
}
// NewRPCBackend creates a new binding backend to an RPC provider that can be
// used to interact with remote contracts.
func NewRPCBackend(client rpc.Client) bind.ContractBackend {
return &rpcBackend{
client: client,
}
}
// request is a JSON RPC request package assembled internally from the client
// method calls.
type request struct {
JSONRPC string `json:"jsonrpc"` // Version of the JSON RPC protocol, always set to 2.0
ID int `json:"id"` // Auto incrementing ID number for this request
Method string `json:"method"` // Remote procedure name to invoke on the server
Params []interface{} `json:"params"` // List of parameters to pass through (keep types simple)
}
// response is a JSON RPC response package sent back from the API server.
type response struct {
JSONRPC string `json:"jsonrpc"` // Version of the JSON RPC protocol, always set to 2.0
ID int `json:"id"` // Auto incrementing ID number for this request
Error *failure `json:"error"` // Any error returned by the remote side
Result json.RawMessage `json:"result"` // Whatever the remote side sends us in reply
}
// failure is a JSON RPC response error field sent back from the API server.
type failure struct {
Code int `json:"code"` // JSON RPC error code associated with the failure
Message string `json:"message"` // Specific error message of the failure
}
// request forwards an API request to the RPC server, and parses the response.
//
// This is currently painfully non-concurrent, but it will have to do until we
// find the time for niceties like this :P
func (b *rpcBackend) request(ctx context.Context, method string, params []interface{}) (json.RawMessage, error) {
b.lock.Lock()
defer b.lock.Unlock()
if ctx == nil {
ctx = context.Background()
}
// Ugly hack to serialize an empty list properly
if params == nil {
params = []interface{}{}
}
// Assemble the request object
reqID := int(atomic.AddUint32(&b.autoid, 1))
req := &request{
JSONRPC: "2.0",
ID: reqID,
Method: method,
Params: params,
}
if err := b.client.Send(req); err != nil {
return nil, err
}
res := new(response)
errc := make(chan error, 1)
go func() {
errc <- b.client.Recv(res)
}()
select {
case err := <-errc:
if err != nil {
return nil, err
}
case <-ctx.Done():
return nil, ctx.Err()
}
if res.Error != nil {
if res.Error.Message == bind.ErrNoCode.Error() {
return nil, bind.ErrNoCode
}
return nil, fmt.Errorf("remote error: %s", res.Error.Message)
}
return res.Result, nil
func NewRPCBackend(client *rpc.Client) bind.ContractBackend {
return &rpcBackend{client: client}
}
// HasCode implements ContractVerifier.HasCode by retrieving any code associated
// with the contract from the remote node, and checking its size.
func (b *rpcBackend) HasCode(ctx context.Context, contract common.Address, pending bool) (bool, error) {
// Execute the RPC code retrieval
block := "latest"
if pending {
block = "pending"
}
res, err := b.request(ctx, "eth_getCode", []interface{}{contract.Hex(), block})
var hex string
err := b.client.CallContext(ctx, &hex, "eth_getCode", contract, block)
if err != nil {
return false, err
}
var hex string
if err := json.Unmarshal(res, &hex); err != nil {
return false, err
}
// Convert the response back to a Go byte slice and return
return len(common.FromHex(hex)) > 0, nil
}
// ContractCall implements ContractCaller.ContractCall, delegating the execution of
// a contract call to the remote node, returning the reply to for local processing.
func (b *rpcBackend) ContractCall(ctx context.Context, contract common.Address, data []byte, pending bool) ([]byte, error) {
// Pack up the request into an RPC argument
args := struct {
To common.Address `json:"to"`
Data string `json:"data"`
@ -157,63 +68,43 @@ func (b *rpcBackend) ContractCall(ctx context.Context, contract common.Address,
To: contract,
Data: common.ToHex(data),
}
// Execute the RPC call and retrieve the response
block := "latest"
if pending {
block = "pending"
}
res, err := b.request(ctx, "eth_call", []interface{}{args, block})
var hex string
err := b.client.CallContext(ctx, &hex, "eth_call", args, block)
if err != nil {
return nil, err
}
var hex string
if err := json.Unmarshal(res, &hex); err != nil {
return nil, err
}
// Convert the response back to a Go byte slice and return
return common.FromHex(hex), nil
}
// PendingAccountNonce implements ContractTransactor.PendingAccountNonce, delegating
// the current account nonce retrieval to the remote node.
func (b *rpcBackend) PendingAccountNonce(ctx context.Context, account common.Address) (uint64, error) {
res, err := b.request(ctx, "eth_getTransactionCount", []interface{}{account.Hex(), "pending"})
var hex rpc.HexNumber
err := b.client.CallContext(ctx, &hex, "eth_getTransactionCount", account.Hex(), "pending")
if err != nil {
return 0, err
}
var hex string
if err := json.Unmarshal(res, &hex); err != nil {
return 0, err
}
nonce, ok := new(big.Int).SetString(hex, 0)
if !ok {
return 0, fmt.Errorf("invalid nonce hex: %s", hex)
}
return nonce.Uint64(), nil
return hex.Uint64(), nil
}
// SuggestGasPrice implements ContractTransactor.SuggestGasPrice, delegating the
// gas price oracle request to the remote node.
func (b *rpcBackend) SuggestGasPrice(ctx context.Context) (*big.Int, error) {
res, err := b.request(ctx, "eth_gasPrice", nil)
if err != nil {
var hex rpc.HexNumber
if err := b.client.CallContext(ctx, &hex, "eth_gasPrice"); err != nil {
return nil, err
}
var hex string
if err := json.Unmarshal(res, &hex); err != nil {
return nil, err
}
price, ok := new(big.Int).SetString(hex, 0)
if !ok {
return nil, fmt.Errorf("invalid price hex: %s", hex)
}
return price, nil
return (*big.Int)(&hex), nil
}
// EstimateGasLimit implements ContractTransactor.EstimateGasLimit, delegating
// the gas estimation to the remote node.
func (b *rpcBackend) EstimateGasLimit(ctx context.Context, sender common.Address, contract *common.Address, value *big.Int, data []byte) (*big.Int, error) {
// Pack up the request into an RPC argument
args := struct {
From common.Address `json:"from"`
To *common.Address `json:"to"`
@ -226,19 +117,12 @@ func (b *rpcBackend) EstimateGasLimit(ctx context.Context, sender common.Address
Value: rpc.NewHexNumber(value),
}
// Execute the RPC call and retrieve the response
res, err := b.request(ctx, "eth_estimateGas", []interface{}{args})
var hex rpc.HexNumber
err := b.client.CallContext(ctx, &hex, "eth_estimateGas", args)
if err != nil {
return nil, err
}
var hex string
if err := json.Unmarshal(res, &hex); err != nil {
return nil, err
}
estimate, ok := new(big.Int).SetString(hex, 0)
if !ok {
return nil, fmt.Errorf("invalid estimate hex: %s", hex)
}
return estimate, nil
return (*big.Int)(&hex), nil
}
// SendTransaction implements ContractTransactor.SendTransaction, delegating the
@ -248,13 +132,5 @@ func (b *rpcBackend) SendTransaction(ctx context.Context, tx *types.Transaction)
if err != nil {
return err
}
res, err := b.request(ctx, "eth_sendRawTransaction", []interface{}{common.ToHex(data)})
if err != nil {
return err
}
var hex string
if err := json.Unmarshal(res, &hex); err != nil {
return err
}
return nil
return b.client.CallContext(ctx, nil, "eth_sendRawTransaction", common.ToHex(data))
}