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291 lines
8.7 KiB
291 lines
8.7 KiB
package core
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import (
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"context"
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"fmt"
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"github.com/pkg/errors"
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tmpubsub "github.com/tendermint/tendermint/libs/pubsub"
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tmquery "github.com/tendermint/tendermint/libs/pubsub/query"
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ctypes "github.com/tendermint/tendermint/rpc/core/types"
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rpctypes "github.com/tendermint/tendermint/rpc/lib/types"
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)
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// Subscribe for events via WebSocket.
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//
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// To tell which events you want, you need to provide a query. query is a
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// string, which has a form: "condition AND condition ..." (no OR at the
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// moment). condition has a form: "key operation operand". key is a string with
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// a restricted set of possible symbols ( \t\n\r\\()"'=>< are not allowed).
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// operation can be "=", "<", "<=", ">", ">=", "CONTAINS". operand can be a
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// string (escaped with single quotes), number, date or time.
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//
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// Examples:
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// tm.event = 'NewBlock' # new blocks
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// tm.event = 'CompleteProposal' # node got a complete proposal
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// tm.event = 'Tx' AND tx.hash = 'XYZ' # single transaction
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// tm.event = 'Tx' AND tx.height = 5 # all txs of the fifth block
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// tx.height = 5 # all txs of the fifth block
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//
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// Tendermint provides a few predefined keys: tm.event, tx.hash and tx.height.
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// Note for transactions, you can define additional keys by providing events with
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// DeliverTx response.
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//
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// import (
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// abci "github.com/tendermint/tendermint/abci/types"
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// "github.com/tendermint/tendermint/libs/pubsub/query"
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// )
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//
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// abci.ResponseDeliverTx{
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// Events: []abci.Event{
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// {
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// Type: "rewards.withdraw",
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// Attributes: cmn.KVPairs{
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// cmn.KVPair{Key: []byte("address"), Value: []byte("AddrA")},
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// cmn.KVPair{Key: []byte("source"), Value: []byte("SrcX")},
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// cmn.KVPair{Key: []byte("amount"), Value: []byte("...")},
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// cmn.KVPair{Key: []byte("balance"), Value: []byte("...")},
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// },
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// },
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// {
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// Type: "rewards.withdraw",
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// Attributes: cmn.KVPairs{
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// cmn.KVPair{Key: []byte("address"), Value: []byte("AddrB")},
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// cmn.KVPair{Key: []byte("source"), Value: []byte("SrcY")},
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// cmn.KVPair{Key: []byte("amount"), Value: []byte("...")},
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// cmn.KVPair{Key: []byte("balance"), Value: []byte("...")},
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// },
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// },
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// {
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// Type: "transfer",
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// Attributes: cmn.KVPairs{
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// cmn.KVPair{Key: []byte("sender"), Value: []byte("AddrC")},
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// cmn.KVPair{Key: []byte("recipient"), Value: []byte("AddrD")},
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// cmn.KVPair{Key: []byte("amount"), Value: []byte("...")},
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// },
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// },
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// },
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// }
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//
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// All events are indexed by a composite key of the form {eventType}.{evenAttrKey}.
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// In the above examples, the following keys would be indexed:
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// - rewards.withdraw.address
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// - rewards.withdraw.source
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// - rewards.withdraw.amount
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// - rewards.withdraw.balance
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// - transfer.sender
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// - transfer.recipient
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// - transfer.amount
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//
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// Multiple event types with duplicate keys are allowed and are meant to
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// categorize unique and distinct events. In the above example, all events
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// indexed under the key `rewards.withdraw.address` will have the following
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// values stored and queryable:
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//
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// - AddrA
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// - AddrB
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//
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// To create a query for txs where address AddrA withdrew rewards:
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// query.MustParse("tm.event = 'Tx' AND rewards.withdraw.address = 'AddrA'")
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//
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// To create a query for txs where address AddrA withdrew rewards from source Y:
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// query.MustParse("tm.event = 'Tx' AND rewards.withdraw.address = 'AddrA' AND rewards.withdraw.source = 'Y'")
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//
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// To create a query for txs where AddrA transferred funds:
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// query.MustParse("tm.event = 'Tx' AND transfer.sender = 'AddrA'")
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//
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// The following queries would return no results:
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// query.MustParse("tm.event = 'Tx' AND transfer.sender = 'AddrZ'")
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// query.MustParse("tm.event = 'Tx' AND rewards.withdraw.address = 'AddrZ'")
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// query.MustParse("tm.event = 'Tx' AND rewards.withdraw.source = 'W'")
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//
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// See list of all possible events here
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// https://godoc.org/github.com/tendermint/tendermint/types#pkg-constants
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//
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// For complete query syntax, check out
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// https://godoc.org/github.com/tendermint/tendermint/libs/pubsub/query.
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//
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// ```go
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// import "github.com/tendermint/tendermint/types"
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//
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// client := client.NewHTTP("tcp://0.0.0.0:26657", "/websocket")
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// err := client.Start()
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// if err != nil {
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// // handle error
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// }
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// defer client.Stop()
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// ctx, cancel := context.WithTimeout(context.Background(), 1 * time.Second)
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// defer cancel()
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// query := "tm.event = 'Tx' AND tx.height = 3"
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// txs, err := client.Subscribe(ctx, "test-client", query)
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// if err != nil {
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// // handle error
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// }
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//
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// go func() {
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// for e := range txs {
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// fmt.Println("got ", e.Data.(types.EventDataTx))
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// }
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// }()
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// ```
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//
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// > The above command returns JSON structured like this:
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//
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// ```json
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// {
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// "error": "",
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// "result": {},
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// "id": "",
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// "jsonrpc": "2.0"
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// }
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// ```
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//
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// ### Query Parameters
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//
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// | Parameter | Type | Default | Required | Description |
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// |-----------+--------+---------+----------+-------------|
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// | query | string | "" | true | Query |
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//
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// <aside class="notice">WebSocket only</aside>
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func Subscribe(ctx *rpctypes.Context, query string) (*ctypes.ResultSubscribe, error) {
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addr := ctx.RemoteAddr()
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if eventBus.NumClients() >= config.MaxSubscriptionClients {
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return nil, fmt.Errorf("max_subscription_clients %d reached", config.MaxSubscriptionClients)
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} else if eventBus.NumClientSubscriptions(addr) >= config.MaxSubscriptionsPerClient {
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return nil, fmt.Errorf("max_subscriptions_per_client %d reached", config.MaxSubscriptionsPerClient)
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}
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logger.Info("Subscribe to query", "remote", addr, "query", query)
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q, err := tmquery.New(query)
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if err != nil {
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return nil, errors.Wrap(err, "failed to parse query")
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}
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subCtx, cancel := context.WithTimeout(ctx.Context(), SubscribeTimeout)
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defer cancel()
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sub, err := eventBus.Subscribe(subCtx, addr, q)
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if err != nil {
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return nil, err
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}
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go func() {
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for {
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select {
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case msg := <-sub.Out():
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resultEvent := &ctypes.ResultEvent{Query: query, Data: msg.Data(), Events: msg.Events()}
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ctx.WSConn.TryWriteRPCResponse(
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rpctypes.NewRPCSuccessResponse(
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ctx.WSConn.Codec(),
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rpctypes.JSONRPCStringID(fmt.Sprintf("%v#event", ctx.JSONReq.ID)),
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resultEvent,
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))
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case <-sub.Cancelled():
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if sub.Err() != tmpubsub.ErrUnsubscribed {
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var reason string
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if sub.Err() == nil {
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reason = "Tendermint exited"
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} else {
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reason = sub.Err().Error()
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}
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ctx.WSConn.TryWriteRPCResponse(
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rpctypes.RPCServerError(rpctypes.JSONRPCStringID(
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fmt.Sprintf("%v#event", ctx.JSONReq.ID)),
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fmt.Errorf("subscription was cancelled (reason: %s)", reason),
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))
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}
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return
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}
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}
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}()
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return &ctypes.ResultSubscribe{}, nil
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}
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// Unsubscribe from events via WebSocket.
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//
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// ```go
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// client := client.NewHTTP("tcp://0.0.0.0:26657", "/websocket")
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// err := client.Start()
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// if err != nil {
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// // handle error
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// }
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// defer client.Stop()
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// query := "tm.event = 'Tx' AND tx.height = 3"
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// err = client.Unsubscribe(context.Background(), "test-client", query)
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// if err != nil {
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// // handle error
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// }
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// ```
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//
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// > The above command returns JSON structured like this:
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//
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// ```json
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// {
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// "error": "",
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// "result": {},
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// "id": "",
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// "jsonrpc": "2.0"
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// }
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// ```
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//
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// ### Query Parameters
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//
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// | Parameter | Type | Default | Required | Description |
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// |-----------+--------+---------+----------+-------------|
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// | query | string | "" | true | Query |
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//
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// <aside class="notice">WebSocket only</aside>
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func Unsubscribe(ctx *rpctypes.Context, query string) (*ctypes.ResultUnsubscribe, error) {
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addr := ctx.RemoteAddr()
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logger.Info("Unsubscribe from query", "remote", addr, "query", query)
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q, err := tmquery.New(query)
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if err != nil {
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return nil, errors.Wrap(err, "failed to parse query")
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}
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err = eventBus.Unsubscribe(context.Background(), addr, q)
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if err != nil {
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return nil, err
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}
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return &ctypes.ResultUnsubscribe{}, nil
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}
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// Unsubscribe from all events via WebSocket.
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//
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// ```go
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// client := client.NewHTTP("tcp://0.0.0.0:26657", "/websocket")
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// err := client.Start()
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// if err != nil {
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// // handle error
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// }
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// defer client.Stop()
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// err = client.UnsubscribeAll(context.Background(), "test-client")
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// if err != nil {
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// // handle error
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// }
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// ```
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//
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// > The above command returns JSON structured like this:
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//
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// ```json
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// {
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// "error": "",
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// "result": {},
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// "id": "",
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// "jsonrpc": "2.0"
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// }
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// ```
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//
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// <aside class="notice">WebSocket only</aside>
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func UnsubscribeAll(ctx *rpctypes.Context) (*ctypes.ResultUnsubscribe, error) {
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addr := ctx.RemoteAddr()
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logger.Info("Unsubscribe from all", "remote", addr)
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err := eventBus.UnsubscribeAll(context.Background(), addr)
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if err != nil {
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return nil, err
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}
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return &ctypes.ResultUnsubscribe{}, nil
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}
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