package rpc import ( "bytes" "context" "encoding/json" "fmt" "net" "net/http" "net/url" "sync" "time" "github.com/CityOfZion/neo-go/pkg/core" "github.com/CityOfZion/neo-go/pkg/core/transaction" "github.com/CityOfZion/neo-go/pkg/crypto/keys" "github.com/CityOfZion/neo-go/pkg/util" "github.com/pkg/errors" ) const ( defaultDialTimeout = 4 * time.Second defaultRequestTimeout = 4 * time.Second defaultClientVersion = "2.0" ) // Client represents the middleman for executing JSON RPC calls // to remote NEO RPC nodes. type Client struct { // The underlying http client. It's never a good practice to use // the http.DefaultClient, therefore we will role our own. cliMu *sync.Mutex cli *http.Client endpoint *url.URL ctx context.Context version string wifMu *sync.Mutex wif *keys.WIF balancerMu *sync.Mutex balancer BalanceGetter } // ClientOptions defines options for the RPC client. // All Values are optional. If any duration is not specified // a default of 3 seconds will be used. type ClientOptions struct { Cert string Key string CACert string DialTimeout time.Duration Client *http.Client // Version is the version of the client that will be send // along with the request body. If no version is specified // the default version (currently 2.0) will be used. Version string } // NewClient returns a new Client ready to use. func NewClient(ctx context.Context, endpoint string, opts ClientOptions) (*Client, error) { url, err := url.Parse(endpoint) if err != nil { return nil, err } if opts.Version == "" { opts.Version = defaultClientVersion } if opts.Client == nil { opts.Client = &http.Client{ Transport: &http.Transport{ DialContext: (&net.Dialer{ Timeout: opts.DialTimeout, }).DialContext, }, } } // TODO(@antdm): Enable SSL. if opts.Cert != "" && opts.Key != "" { } if opts.Client.Timeout == 0 { opts.Client.Timeout = defaultRequestTimeout } return &Client{ ctx: ctx, cli: opts.Client, cliMu: new(sync.Mutex), balancerMu: new(sync.Mutex), wifMu: new(sync.Mutex), endpoint: url, version: opts.Version, }, nil } // WIF returns WIF structure associated with the client. func (c *Client) WIF() keys.WIF { c.wifMu.Lock() defer c.wifMu.Unlock() return keys.WIF{ Version: c.wif.Version, Compressed: c.wif.Compressed, PrivateKey: c.wif.PrivateKey, S: c.wif.S, } } // SetWIF decodes given WIF and adds some wallet // data to client. Useful for RPC calls that require an open wallet. func (c *Client) SetWIF(wif string) error { c.wifMu.Lock() defer c.wifMu.Unlock() decodedWif, err := keys.WIFDecode(wif, 0x00) if err != nil { return errors.Wrap(err, "Failed to decode WIF; failed to add WIF to client ") } c.wif = decodedWif return nil } // Balancer is a getter for balance field. func (c *Client) Balancer() BalanceGetter { c.balancerMu.Lock() defer c.balancerMu.Unlock() return c.balancer } // SetBalancer is a setter for balance field. func (c *Client) SetBalancer(b BalanceGetter) { c.balancerMu.Lock() defer c.balancerMu.Unlock() if b != nil { c.balancer = b } } // Client is a getter for client field. func (c *Client) Client() *http.Client { c.cliMu.Lock() defer c.cliMu.Unlock() return c.cli } // SetClient is a setter for client field. func (c *Client) SetClient(cli *http.Client) { c.cliMu.Lock() defer c.cliMu.Unlock() if cli != nil { c.cli = cli } } // CalculateInputs creates input transactions for the specified amount of given // asset belonging to specified address. This implementation uses GetUnspents // JSON-RPC call internally, so make sure your RPC server suppors that. func (c *Client) CalculateInputs(address string, asset util.Uint256, cost util.Fixed8) ([]transaction.Input, util.Fixed8, error) { var utxos core.UnspentBalances resp, err := c.GetUnspents(address) if err != nil || resp.Error != nil { if err == nil { err = fmt.Errorf("remote returned %d: %s", resp.Error.Code, resp.Error.Message) } return nil, util.Fixed8(0), errors.Wrapf(err, "cannot get balance for address %v", address) } for _, ubi := range resp.Result.Balance { if asset.Equals(ubi.AssetHash) { utxos = ubi.Unspents break } } return unspentsToInputs(utxos, cost) } func (c *Client) performRequest(method string, p params, v interface{}) error { var ( r = request{ JSONRPC: c.version, Method: method, Params: p.values, ID: 1, } buf = new(bytes.Buffer) ) if err := json.NewEncoder(buf).Encode(r); err != nil { return err } req, err := http.NewRequest("POST", c.endpoint.String(), buf) if err != nil { return err } resp, err := c.Client().Do(req) if err != nil { return err } defer resp.Body.Close() if resp.StatusCode != http.StatusOK { return fmt.Errorf("remote responded with a non 200 response: %d", resp.StatusCode) } return json.NewDecoder(resp.Body).Decode(v) } // Ping attempts to create a connection to the endpoint. // and returns an error if there is one. func (c *Client) Ping() error { conn, err := net.DialTimeout("tcp", c.endpoint.Host, defaultDialTimeout) if err != nil { return err } _ = conn.Close() return nil }