package core import ( "context" "fmt" "github.com/pkg/errors" tmquery "github.com/tendermint/tendermint/libs/pubsub/query" ctypes "github.com/tendermint/tendermint/rpc/core/types" rpctypes "github.com/tendermint/tendermint/rpc/lib/types" tmtypes "github.com/tendermint/tendermint/types" ) // Subscribe for events via WebSocket. // // To tell which events you want, you need to provide a query. query is a // string, which has a form: "condition AND condition ..." (no OR at the // moment). condition has a form: "key operation operand". key is a string with // a restricted set of possible symbols ( \t\n\r\\()"'=>< are not allowed). // operation can be "=", "<", "<=", ">", ">=", "CONTAINS". operand can be a // string (escaped with single quotes), number, date or time. // // Examples: // tm.event = 'NewBlock' # new blocks // tm.event = 'CompleteProposal' # node got a complete proposal // tm.event = 'Tx' AND tx.hash = 'XYZ' # single transaction // tm.event = 'Tx' AND tx.height = 5 # all txs of the fifth block // tx.height = 5 # all txs of the fifth block // // Tendermint provides a few predefined keys: tm.event, tx.hash and tx.height. // Note for transactions, you can define additional keys by providing tags with // DeliverTx response. // // DeliverTx{ // Tags: []*KVPair{ // "agent.name": "K", // } // } // // tm.event = 'Tx' AND agent.name = 'K' // tm.event = 'Tx' AND account.created_at >= TIME 2013-05-03T14:45:00Z // tm.event = 'Tx' AND contract.sign_date = DATE 2017-01-01 // tm.event = 'Tx' AND account.owner CONTAINS 'Igor' // // See list of all possible events here // https://godoc.org/github.com/tendermint/tendermint/types#pkg-constants // // For complete query syntax, check out // https://godoc.org/github.com/tendermint/tendermint/libs/pubsub/query. // // ```go // import "github.com/tendermint/tendermint/libs/pubsub/query" // import "github.com/tendermint/tendermint/types" // // client := client.NewHTTP("tcp://0.0.0.0:26657", "/websocket") // err := client.Start() // if err != nil { // // handle error // } // defer client.Stop() // ctx, cancel := context.WithTimeout(context.Background(), timeout) // defer cancel() // query := query.MustParse("tm.event = 'Tx' AND tx.height = 3") // txs := make(chan interface{}) // err = client.Subscribe(ctx, "test-client", query, txs) // // go func() { // for e := range txs { // fmt.Println("got ", e.(types.EventDataTx)) // } // }() // ``` // // > The above command returns JSON structured like this: // // ```json // { // "error": "", // "result": {}, // "id": "", // "jsonrpc": "2.0" // } // ``` // // ### Query Parameters // // | Parameter | Type | Default | Required | Description | // |-----------+--------+---------+----------+-------------| // | query | string | "" | true | Query | // // func Subscribe(wsCtx rpctypes.WSRPCContext, query string) (*ctypes.ResultSubscribe, error) { addr := wsCtx.GetRemoteAddr() 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") } ctx, cancel := context.WithTimeout(context.Background(), subscribeTimeout) defer cancel() ch := make(chan interface{}) err = eventBusFor(wsCtx).Subscribe(ctx, addr, q, ch) if err != nil { return nil, err } go func() { for event := range ch { tmResult := &ctypes.ResultEvent{query, event.(tmtypes.TMEventData)} wsCtx.TryWriteRPCResponse(rpctypes.NewRPCSuccessResponse(wsCtx.Codec(), rpctypes.JSONRPCStringID(fmt.Sprintf("%v#event", wsCtx.Request.ID)), tmResult)) } }() return &ctypes.ResultSubscribe{}, nil } // Unsubscribe from events via WebSocket. // // ```go // client := client.NewHTTP("tcp://0.0.0.0:26657", "/websocket") // err := client.Start() // if err != nil { // // handle error // } // defer client.Stop() // err = client.Unsubscribe("test-client", query) // ``` // // > The above command returns JSON structured like this: // // ```json // { // "error": "", // "result": {}, // "id": "", // "jsonrpc": "2.0" // } // ``` // // ### Query Parameters // // | Parameter | Type | Default | Required | Description | // |-----------+--------+---------+----------+-------------| // | query | string | "" | true | Query | // // func Unsubscribe(wsCtx rpctypes.WSRPCContext, query string) (*ctypes.ResultUnsubscribe, error) { addr := wsCtx.GetRemoteAddr() 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 = eventBusFor(wsCtx).Unsubscribe(context.Background(), addr, q) if err != nil { return nil, err } return &ctypes.ResultUnsubscribe{}, nil } // Unsubscribe from all events via WebSocket. // // ```go // client := client.NewHTTP("tcp://0.0.0.0:26657", "/websocket") // err := client.Start() // if err != nil { // // handle error // } // defer client.Stop() // err = client.UnsubscribeAll("test-client") // ``` // // > The above command returns JSON structured like this: // // ```json // { // "error": "", // "result": {}, // "id": "", // "jsonrpc": "2.0" // } // ``` // // func UnsubscribeAll(wsCtx rpctypes.WSRPCContext) (*ctypes.ResultUnsubscribe, error) { addr := wsCtx.GetRemoteAddr() logger.Info("Unsubscribe from all", "remote", addr) err := eventBusFor(wsCtx).UnsubscribeAll(context.Background(), addr) if err != nil { return nil, err } return &ctypes.ResultUnsubscribe{}, nil } func eventBusFor(wsCtx rpctypes.WSRPCContext) tmtypes.EventBusSubscriber { es := wsCtx.GetEventSubscriber() if es == nil { es = eventBus } return es }