Server-Sent Events in Go

Memory usage

◼︎ Heap bytes
◼︎ Stack bytes

Allocations per second

◼︎ Mallocs / sec
◼︎ Frees / sec

Server-side (Go)

func streamRoom(c *gin.Context) {
    roomid := c.ParamValue("roomid")
    listener := openListener(roomid)
    statsTicker := time.NewTicker(1 * time.Second)
    defer closeListener(roomid, listener)
    defer statsTicker.Stop()

    c.Stream(func(w io.Writer) bool {
        select {
        case msg := <-listener:
            c.SSEvent("message", msg)
        case <-statsTicker.C:
            c.SSEvent("stats", Stats())
        }
        return true
    })
}

Client-side (JS)

function StartSSE(roomid) {
    var source = new EventSource('/stream/'+roomid);
    source.addEventListener('message', newChatMessage, false);
    source.addEventListener('stats', stats, false);
}

SSE package

import "github.com/manucorporat/sse"

func httpHandler(w http.ResponseWriter, req *http.Request) {
    // data can be a primitive like a string, an integer or a float
    sse.Encode(w, sse.Event{
        Event: "message",
        Data:  "some data\nmore data",
    })

    // also a complex type, like a map, a struct or a slice
    sse.Encode(w, sse.Event{
        Id:    "124",
        Event: "message",
        Data: map[string]interface{}{
            "user":    "manu",
            "date":    time.Now().Unix(),
            "content": "hi!",
        },
    })
}

event: message
data: some data\\nmore data

id: 124
event: message
data: {"content":"hi!","date":1431540810,"user":"manu"}