go服务器与vue客户端的sse实现

go server

1	data: something happend!\n\n

第二个 \n 表示这个 event 结束，可以发给客户端了。第一个 \n 主要是为了有时要传输多行数据时，例如传个 json：

1
2
3

data: {\n
data: "foo": "bar"\n
data: }\n\n

上面都属于 message 这个类型，如果想发送别的类型可以通过 event 字段自定义：

1 2	event: close\n data: play enough\n\n

注意仍然需要带上 data 字段。

package main

import (
	"fmt"
	"log"
	"net/http"
	"time"
)

func handleSSE(w http.ResponseWriter, r *http.Request) {

	appId := r.URL.Query()["appId"]
	page := r.URL.Query()["page"]
	pageSize := r.URL.Query()["pageSize"]

	w.Header().Set("Content-Type", "text/event-stream")
	w.Header().Set("Cache-Control", "no-cache")
	w.Header().Set("Connection", "keep-alive")
	w.Header().Set("Access-Control-Allow-Origin", "*")

	flusher, ok := w.(http.Flusher)
	if !ok {
		log.Panic("server not support")
	}
	for i := 0; i < 10; i++ {
		time.Sleep(5 * time.Second)
		fmt.Fprintf(w, "data: %d%s%s%s\n\n", i, appId[0], page[0], pageSize[0])
		flusher.Flush()
	}
	fmt.Fprintf(w, "event: close\ndata: close\n\n") // 一定要带上data，否则无效
}

func main() {
	http.Handle("/event", http.HandlerFunc(handleSSE))
	http.ListenAndServe(":8000", nil)
}

vue client

客户端可以在 url 加上一些参数，但是如果想传大量参数，那就没什么直接的方法了，像 post 那样。只能另想方法，例如先发个 post 请求把数据发到服务器，再 SSE ，并通过 session 或别的将这两者关联。

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <meta http-equiv="X-UA-Compatible" content="ie=edge">
    <title>Server-Send Event</title>
</head>
<body>
    <div id="app">
        <button @click="create">Server-Send Event</button>
    </div>
    <script src="https://cdn.jsdelivr.net/npm/vue/dist/vue.js"></script>
    <script>
        var app = new Vue({
            el: "#app",
            data: {
                page: 1,
                pageSize: 30,
                appId: 10003,
            },
            methods: {
                create: function() {
                    let url = 'http://localhost:8000/event?page='+this.page+'&pageSize='+this.pageSize+'&appId='+this.appId
                    let es = new EventSource(url);
                    es.addEventListener('message', event => {
                        console.log(event.data);
                    });
                    es.addEventListener('error', event => {
                        if (event.readyState == EventSource.CLOSED) {
                            console.log('event was closed');
                        };
                    });
                    es.addEventListener('close', event => {
                        console.log(event.type);
                        es.close();
                    });
                }
            },
        })
    </script>
</body>
<script>

</script>
</html>

vue client post

利用addEventListener监听事件。

// https://github.com/mpetazzoni/sse.js
startConv: function () {
let url = 'http://localhost:8000/conv'
let body = {
    "content": this.question,
    "parent_message_id": this.parentMessageID,
    "conversation_id": this.conversationId
}
console.log(body)
var source = new SSE(url, {
    headers: { 'Content-Type': 'application/json', 'Accept': 'text/event-stream' },
    payload: JSON.stringify(body)
});
this.answer = ''
source.addEventListener('message', e => {
    if (e.data != '[DONE]' && e.data != '[DONE]event: closeclose') {
        var payload = JSON.parse(e.data);
        if (payload !== undefined) {
            this.conversationId = payload.conversation_id
            this.parentMessageID = payload.message.id
            this.answer = payload.message.content.parts[0]
        }
    }
});
source.stream();
}