path: root/rpc/subscription_test.go

// Copyright 2016 The go-ethereum Authors
// This file is part of the go-ethereum library.
//
// The go-ethereum library is free software: you can redistribute it and/or modify
// it under the terms of the GNU Lesser General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// The go-ethereum library 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 Lesser General Public License for more details.
//
// You should have received a copy of the GNU Lesser General Public License
// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.

package rpc

import (
    "encoding/json"
    "net"
    "sync"
    "testing"
    "time"

    "golang.org/x/net/context"
)

type NotificationTestService struct {
    mu           sync.Mutex
    unsubscribed bool

    gotHangSubscriptionReq  chan struct{}
    unblockHangSubscription chan struct{}
}

func (s *NotificationTestService) Echo(i int) int {
    return i
}

func (s *NotificationTestService) wasUnsubCallbackCalled() bool {
    s.mu.Lock()
    defer s.mu.Unlock()
    return s.unsubscribed
}

func (s *NotificationTestService) Unsubscribe(subid string) {
    s.mu.Lock()
    s.unsubscribed = true
    s.mu.Unlock()
}

func (s *NotificationTestService) SomeSubscription(ctx context.Context, n, val int) (*Subscription, error) {
    notifier, supported := NotifierFromContext(ctx)
    if !supported {
        return nil, ErrNotificationsUnsupported
    }

    // by explicitly creating an subscription we make sure that the subscription id is send back to the client
    // before the first subscription.Notify is called. Otherwise the events might be send before the response
    // for the eth_subscribe method.
    subscription := notifier.CreateSubscription()

    go func() {
        // test expects n events, if we begin sending event immediately some events
        // will probably be dropped since the subscription ID might not be send to
        // the client.
        time.Sleep(5 * time.Second)
        for i := 0; i < n; i++ {
            if err := notifier.Notify(subscription.ID, val+i); err != nil {
                return
            }
        }

        select {
        case <-notifier.Closed():
            s.mu.Lock()
            s.unsubscribed = true
            s.mu.Unlock()
        case <-subscription.Err():
            s.mu.Lock()
            s.unsubscribed = true
            s.mu.Unlock()
        }
    }()

    return subscription, nil
}

// HangSubscription blocks on s.unblockHangSubscription before
// sending anything.
func (s *NotificationTestService) HangSubscription(ctx context.Context, val int) (*Subscription, error) {
    notifier, supported := NotifierFromContext(ctx)
    if !supported {
        return nil, ErrNotificationsUnsupported
    }

    s.gotHangSubscriptionReq <- struct{}{}
    <-s.unblockHangSubscription
    subscription := notifier.CreateSubscription()

    go func() {
        notifier.Notify(subscription.ID, val)
    }()
    return subscription, nil
}

func TestNotifications(t *testing.T) {
    server := NewServer()
    service := &NotificationTestService{}

    if err := server.RegisterName("eth", service); err != nil {
        t.Fatalf("unable to register test service %v", err)
    }

    clientConn, serverConn := net.Pipe()

    go server.ServeCodec(NewJSONCodec(serverConn), OptionMethodInvocation|OptionSubscriptions)

    out := json.NewEncoder(clientConn)
    in := json.NewDecoder(clientConn)

    n := 5
    val := 12345
    request := map[string]interface{}{
        "id":      1,
        "method":  "eth_subscribe",
        "version": "2.0",
        "params":  []interface{}{"someSubscription", n, val},
    }

    // create subscription
    if err := out.Encode(request); err != nil {
        t.Fatal(err)
    }

    var subid string
    response := jsonSuccessResponse{Result: subid}
    if err := in.Decode(&response); err != nil {
        t.Fatal(err)
    }

    var ok bool
    if _, ok = response.Result.(string); !ok {
        t.Fatalf("expected subscription id, got %T", response.Result)
    }

    for i := 0; i < n; i++ {
        var notification jsonNotification
        if err := in.Decode(&notification); err != nil {
            t.Fatalf("%v", err)
        }

        if int(notification.Params.Result.(float64)) != val+i {
            t.Fatalf("expected %d, got %d", val+i, notification.Params.Result)
        }
    }

    clientConn.Close() // causes notification unsubscribe callback to be called
    time.Sleep(1 * time.Second)

    if !service.wasUnsubCallbackCalled() {
        t.Error("unsubscribe callback not called after closing connection")
    }
}