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package core
import (
"context"
"fmt"
"github.com/pkg/errors"
tmpubsub "github.com/tendermint/tendermint/libs/pubsub"
tmquery "github.com/tendermint/tendermint/libs/pubsub/query"
ctypes "github.com/tendermint/tendermint/rpc/core/types"
rpctypes "github.com/tendermint/tendermint/rpc/lib/types"
)
// Subscribe for events via WebSocket.
// More: https://tendermint.com/rpc/#/Websocket/subscribe
func Subscribe(ctx *rpctypes.Context, query string) (*ctypes.ResultSubscribe, error) {
addr := ctx.RemoteAddr()
if eventBus.NumClients() >= config.MaxSubscriptionClients {
return nil, fmt.Errorf("max_subscription_clients %d reached", config.MaxSubscriptionClients)
} else if eventBus.NumClientSubscriptions(addr) >= config.MaxSubscriptionsPerClient {
return nil, fmt.Errorf("max_subscriptions_per_client %d reached", config.MaxSubscriptionsPerClient)
}
logger.Info("Subscribe to query", "remote", addr, "query", query)
q, err := tmquery.New(query)
if err != nil {
return nil, errors.Wrap(err, "failed to parse query")
}
subCtx, cancel := context.WithTimeout(ctx.Context(), SubscribeTimeout)
defer cancel()
sub, err := eventBus.Subscribe(subCtx, addr, q)
if err != nil {
return nil, err
}
go func() {
for {
select {
case msg := <-sub.Out():
resultEvent := &ctypes.ResultEvent{Query: query, Data: msg.Data(), Events: msg.Events()}
ctx.WSConn.TryWriteRPCResponse(
rpctypes.NewRPCSuccessResponse(
ctx.WSConn.Codec(),
ctx.JSONReq.ID,
resultEvent,
))
case <-sub.Cancelled():
if sub.Err() != tmpubsub.ErrUnsubscribed {
var reason string
if sub.Err() == nil {
reason = "Tendermint exited"
} else {
reason = sub.Err().Error()
}
ctx.WSConn.TryWriteRPCResponse(
rpctypes.RPCServerError(
ctx.JSONReq.ID,
fmt.Errorf("subscription was cancelled (reason: %s)", reason),
))
}
return
}
}
}()
return &ctypes.ResultSubscribe{}, nil
}
// Unsubscribe from events via WebSocket.
// More: https://tendermint.com/rpc/#/Websocket/unsubscribe
func Unsubscribe(ctx *rpctypes.Context, query string) (*ctypes.ResultUnsubscribe, error) {
addr := ctx.RemoteAddr()
logger.Info("Unsubscribe from query", "remote", addr, "query", query)
q, err := tmquery.New(query)
if err != nil {
return nil, errors.Wrap(err, "failed to parse query")
}
err = eventBus.Unsubscribe(context.Background(), addr, q)
if err != nil {
return nil, err
}
return &ctypes.ResultUnsubscribe{}, nil
}
// UnsubscribeAll from all events via WebSocket.
// More: https://tendermint.com/rpc/#/Websocket/unsubscribe_all
func UnsubscribeAll(ctx *rpctypes.Context) (*ctypes.ResultUnsubscribe, error) {
addr := ctx.RemoteAddr()
logger.Info("Unsubscribe from all", "remote", addr)
err := eventBus.UnsubscribeAll(context.Background(), addr)
if err != nil {
return nil, err
}
return &ctypes.ResultUnsubscribe{}, nil
}