neo-go/pkg/rpc/client/client.go
2022-05-06 14:15:59 +03:00

235 lines
6 KiB
Go

package client
import (
"bytes"
"context"
"encoding/json"
"errors"
"fmt"
"net"
"net/http"
"net/url"
"sync"
"time"
"github.com/nspcc-dev/neo-go/pkg/config/netmode"
"github.com/nspcc-dev/neo-go/pkg/rpc/request"
"github.com/nspcc-dev/neo-go/pkg/rpc/response"
"github.com/nspcc-dev/neo-go/pkg/util"
"go.uber.org/atomic"
)
const (
defaultDialTimeout = 4 * time.Second
defaultRequestTimeout = 4 * time.Second
// Number of blocks after which cache is expired.
cacheTimeout = 100
)
// Client represents the middleman for executing JSON RPC calls
// to remote NEO RPC nodes. Client is thread-safe and can be used from
// multiple goroutines.
type Client struct {
cli *http.Client
endpoint *url.URL
ctx context.Context
opts Options
requestF func(*request.Raw) (*response.Raw, error)
cacheLock sync.RWMutex
// cache stores RPC node related information the client is bound to.
// cache is mostly filled in during Init(), but can also be updated
// during regular Client lifecycle.
cache cache
latestReqID *atomic.Uint64
// getNextRequestID returns an ID to be used for the subsequent request creation.
// It is defined on Client, so that our testing code can override this method
// for the sake of more predictable request IDs generation behavior.
getNextRequestID func() uint64
}
// Options defines options for the RPC client.
// All values are optional. If any duration is not specified,
// a default of 4 seconds will be used.
type Options struct {
// Cert is a client-side certificate, it doesn't work at the moment along
// with the other two options below.
Cert string
Key string
CACert string
DialTimeout time.Duration
RequestTimeout time.Duration
// Limit total number of connections per host. No limit by default.
MaxConnsPerHost int
}
// cache stores cache values for the RPC client methods.
type cache struct {
initDone bool
network netmode.Magic
stateRootInHeader bool
calculateValidUntilBlock calculateValidUntilBlockCache
nativeHashes map[string]util.Uint160
}
// calculateValidUntilBlockCache stores a cached number of validators and
// cache expiration value in blocks.
type calculateValidUntilBlockCache struct {
validatorsCount uint32
expiresAt uint32
}
// New returns a new Client ready to use. You should call Init method to
// initialize network magic the client is operating on.
func New(ctx context.Context, endpoint string, opts Options) (*Client, error) {
cl := new(Client)
err := initClient(ctx, cl, endpoint, opts)
if err != nil {
return nil, err
}
return cl, nil
}
func initClient(ctx context.Context, cl *Client, endpoint string, opts Options) error {
url, err := url.Parse(endpoint)
if err != nil {
return err
}
if opts.DialTimeout <= 0 {
opts.DialTimeout = defaultDialTimeout
}
if opts.RequestTimeout <= 0 {
opts.RequestTimeout = defaultRequestTimeout
}
httpClient := &http.Client{
Transport: &http.Transport{
DialContext: (&net.Dialer{
Timeout: opts.DialTimeout,
}).DialContext,
MaxConnsPerHost: opts.MaxConnsPerHost,
},
Timeout: opts.RequestTimeout,
}
// TODO(@antdm): Enable SSL.
// if opts.Cert != "" && opts.Key != "" {
// }
cl.ctx = ctx
cl.cli = httpClient
cl.endpoint = url
cl.cache = cache{
nativeHashes: make(map[string]util.Uint160),
}
cl.latestReqID = atomic.NewUint64(0)
cl.getNextRequestID = (cl).getRequestID
cl.opts = opts
cl.requestF = cl.makeHTTPRequest
return nil
}
func (c *Client) getRequestID() uint64 {
return c.latestReqID.Inc()
}
// Init sets magic of the network client connected to, stateRootInHeader option
// and native NEO, GAS and Policy contracts scripthashes. This method should be
// called before any header- or block-related requests in order to deserialize
// responses properly.
func (c *Client) Init() error {
version, err := c.GetVersion()
if err != nil {
return fmt.Errorf("failed to get network magic: %w", err)
}
natives, err := c.GetNativeContracts()
if err != nil {
return fmt.Errorf("failed to get native contracts: %w", err)
}
c.cacheLock.Lock()
defer c.cacheLock.Unlock()
c.cache.network = version.Protocol.Network
c.cache.stateRootInHeader = version.Protocol.StateRootInHeader
if version.Protocol.MillisecondsPerBlock == 0 {
c.cache.network = version.Magic
c.cache.stateRootInHeader = version.StateRootInHeader
}
for _, ctr := range natives {
c.cache.nativeHashes[ctr.Manifest.Name] = ctr.Hash
}
c.cache.initDone = true
return nil
}
func (c *Client) performRequest(method string, p request.RawParams, v interface{}) error {
var r = request.Raw{
JSONRPC: request.JSONRPCVersion,
Method: method,
RawParams: p.Values,
ID: c.getNextRequestID(),
}
raw, err := c.requestF(&r)
if raw != nil && raw.Error != nil {
return raw.Error
} else if err != nil {
return err
} else if raw == nil || raw.Result == nil {
return errors.New("no result returned")
}
return json.Unmarshal(raw.Result, v)
}
func (c *Client) makeHTTPRequest(r *request.Raw) (*response.Raw, error) {
var (
buf = new(bytes.Buffer)
raw = new(response.Raw)
)
if err := json.NewEncoder(buf).Encode(r); err != nil {
return nil, err
}
req, err := http.NewRequest("POST", c.endpoint.String(), buf)
if err != nil {
return nil, err
}
resp, err := c.cli.Do(req)
if err != nil {
return nil, err
}
defer resp.Body.Close()
// The node might send us a proper JSON anyway, so look there first and if
// it parses, it has more relevant data than HTTP error code.
err = json.NewDecoder(resp.Body).Decode(raw)
if err != nil {
if resp.StatusCode != http.StatusOK {
err = fmt.Errorf("HTTP %d/%s", resp.StatusCode, http.StatusText(resp.StatusCode))
} else {
err = fmt.Errorf("JSON decoding: %w", err)
}
}
if err != nil {
return nil, err
}
return raw, nil
}
// Ping attempts to create a connection to the endpoint
// and returns an error if there is any.
func (c *Client) Ping() error {
conn, err := net.DialTimeout("tcp", c.endpoint.Host, defaultDialTimeout)
if err != nil {
return err
}
_ = conn.Close()
return nil
}