Method CallContext

api/rpc/client.go:291–318

CallContext performs a JSON-RPC call with the given arguments. If the context is canceled before the call has successfully returned, CallContext returns immediately. The result must be a pointer so that package json can unmarshal into it. You can also pass nil, in which case the result is ignored.

(ctx context.Context, result interface{}, method string, args ...interface{})

// The result must be a pointer so that package json can unmarshal into it. You
// can also pass nil, in which case the result is ignored.
func (c *Client) CallContext(ctx context.Context, result interface{}, method string, args ...interface{}) error {
	msg, err := c.newMessage(method, args...)
	if err != nil {
		return err
	}
	op := &requestOp{ids: []json.RawMessage{msg.ID}, resp: make(chan *jsonrpcMessage, 1)}

	if c.isHTTP {
		err = c.sendHTTP(ctx, op, msg)
	} else {
		err = c.send(ctx, op, msg)
	}
	if err != nil {
		return err
	}

	// dispatch has accepted the request and will close the channel it when it quits.
	switch resp, err := op.wait(ctx); {
	case err != nil:
		return err
	case resp.Error != nil:
		return resp.Error
	case len(resp.Result) == 0:
		return ErrNoResult
	default:
		return json.Unmarshal(resp.Result, &result)
	}
}

// BatchCall sends all given requests as a single batch and waits for the server
// to return a response for all of them.