openresty proxy sse 服务

实际上如果单纯的进行nginx sse 处理很简单，但是我们实际的场景存在数据访问控制以及数据处理
对于此问题，我们可以使用sse client 包装，然后同时将我们的请求endpoint 暴露为一个sse 服务

参考处理图

代码说明

• sse 服务
  基于nodejs 开发的一个测试，基于express

const express = require('express');

const  { sseMiddleware } = require('express-sse-middleware');

const app = express()

app.use(sseMiddleware);

app.get('/sse', (req, res) => {

const sse = res.sse(); // `adding Response.sse()` funciton

let count = 0;

setInterval(() => {

sse.send(String(count++));

}, 1000);

});

app.get('/ssev2', (req, res) => {

res.writeHead(200,{

'Content-Type':'text/event-stream'

});

setInterval(() => {

res.write(`event:xxxx\ndata:${new Date().toLocaleTimeString()}\n\n`)

}, 1000);

});

app.listen(3000);

• nginx 处理
  基于openresty 包含了一个token处理以及基于sse client 获取sse 服务的数据
  nginx.conf

user root;

master_process off;

worker_processes 1;

events {

worker_connections  1024;

}

http {

include       mime.types;

default_type  text/html;

lua_code_cache off;

lua_package_path '/opt/lua/?.lua;;';

real_ip_header     X-Forwarded-For;

resolver 127.0.0.11;

server {

listen 80;

charset utf-8;

proxy_set_header X-Forwarded-For $remote_addr;

proxy_buffering off;

proxy_cache off;

proxy_set_header Connection '';

proxy_http_version 1.1;

chunked_transfer_encoding off;

default_type text/html;

location /ssev2 {

# 代理标准请求

proxy_pass http://sse:3000;

}

location / {

default_type text/event-stream;

# 访问控制

access_by_lua_block {

local token, err = ngx.req.get_headers()["token"]

if token == nil then

ngx.exit(ngx.HTTP_FORBIDDEN)

end

}

// 内容处理，基于了sse client

content_by_lua_block {

local sse = require "resty.sse"

local cjson = require "cjson"

local conn, err = sse.new()

if not conn then

ngx.say("failed to get connection: ", err)

end

local res, err = conn:request_uri("http://sse:3000/ssev2")

if not res then

ngx.say("failed to request: ", err)

return

end

while true

do

local event, err = conn:receive()

if err then

ngx.say(err)

end

if event then

ngx.say(cjson.encode(event))

end

ngx.flush(true)

end

}

}

}

}

运行

nodejs 基于了ncc，整体基于docker-compose
openresty

FROM openresty/openresty:1.21.4.1-0-alpine-fat

RUN apk add --no-cache git &&  /usr/local/openresty/luajit/bin/luarocks install lua-resty-sse

node

FROM node:14.19.3-slim

COPY app/index.js /app/index.js

CMD [ "node","/app/index.js" ]

docker-compose

version: '3'

services:

sse:

build:

context: ./

dockerfile: Dockerfile-node

ports:

- 3000:3000

app:

build: ./

ports:

- "80:80"

volumes:

- "./app/:/opt/app"

- "./nginx.conf:/usr/local/openresty/nginx/conf/nginx.conf"

运行效果

• 默认

• 包含token的

说明

以上是一个简单的测试，可以参考使用

参考资料

​​https://github.com/openresty/lua-nginx-module​​​
​​​https://github.com/wojons/lua-resty-sse​​​
​​​https://github.com/rongfengliang/openresty-sse-proxy​​