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