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Go - Websocket.Send()

Send a message from the websocket to a connection.

import (
  "context"
  "fmt"

  "github.com/nitrictech/go-sdk/nitric"
)

func main() {
  ws, err := nitric.NewWebsocket("public")
  if err != nil {
    return
  }

  ws.Send(context.TODO(), "D28BA458-BFF4-404A", []byte("Hello World"))

  if err := nitric.Run(); err != nil {
    fmt.Println(err)
  }
}

Parameters

Name
ctx
Required
Required
Type
context
Description
The context of the call, used for tracing.
Name
connectionId
Required
Required
Type
string
Description
The ID of the connection which should receive the message.
Name
message
Required
Required
Type
[]byte
Description
The message that should be sent to the connection.

Examples

Broadcasting a message to all connections.

Do not send messages to a connection during it's connect callback, if you need to acknowledge connection, do so by using a topic

import (
	"context"
	"fmt"

	"github.com/nitrictech/go-sdk/handler"
	"github.com/nitrictech/go-sdk/nitric"
)

func main() {
	ws, err := nitric.NewWebsocket("public")
	if err != nil {
		return
	}

	connections, err := nitric.NewKv("connections").Allow(nitric.KvStoreGet, nitric.KvStoreSet, nitric.KvStoreDelete)
	if err != nil {
		return
	}

	// Register a new connection on connect
	ws.On(handler.WebsocketConnect, func(ctx *handler.WebsocketContext, next handler.WebsocketHandler) (*handler.WebsocketContext, error) {
		err := connections.Set(context.TODO(), ctx.Request.ConnectionID(), map[string]interface{}{
			"connectionId": ctx.Request.ConnectionID(),
		})
		if err != nil {
			return ctx, err
		}

		return next(ctx)
	})

	// Remove a registered connection on disconnect
	ws.On(handler.WebsocketDisconnect, func(ctx *handler.WebsocketContext, next handler.WebsocketHandler) (*handler.WebsocketContext, error) {
		err := connections.Delete(context.TODO(), ctx.Request.ConnectionID())
		if err != nil {
			return ctx, err
		}

		return next(ctx)
	})

	// Broadcast message to all the registered websocket connections
	ws.On(handler.WebsocketMessage, func(ctx *handler.WebsocketContext, next handler.WebsocketHandler) (*handler.WebsocketContext, error) {
		connectionStream, err := connections.Keys(context.TODO())
		if err != nil {
			return ctx, err
		}

		for {
			connectionId, err := connectionStream.Recv()
			if err != nil {
				break // reached the end of the documents
			}

			err = ws.Send(context.TODO(), connectionId, []byte(ctx.Request.Message()))
			if err != nil {
				return ctx, err
			}
		}

		return next(ctx)
	})

	if err := nitric.Run(); err != nil {
		fmt.Println(err)
	}
}