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3.2. Openresty 开发
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3.2. Openresty 开发

3.2.1. Hello world!!!

            
[root@netkiller openresty]# vim /srv/openresty/nginx/conf/nginx.conf

    server {
        listen 8080;
        location / {
            default_type text/html;
            content_by_lua_block {
                ngx.say("<p>Hello world!!!</p>")
            }
        }
    }

重载配置文件

            
[root@netkiller openresty]# bin/openresty -s reload

测试效果

            
[root@netkiller openresty]# curl http://www.netkiller.cn
<p>Hello world!!!</p>

3.2.2. 日期和时间

当前时间

            
[root@netkiller lua]# cat time.lua 
print(os.time())

[root@netkiller lua]# lua time.lua 
1670496310

日期

             
[root@netkiller lua]# cat date.lua 
local d1 = os.date("%Y-%m-%d %H:%M:%S")
print(d1)

[root@netkiller lua]# lua date.lua 
2022-12-08 19:07:45        
        
        
             
[root@netkiller lua]# cat date.lua 
local d1 = os.date("%Y-%m-%d %H:%M:%S")
print(d1)

local d2 = os.date("%Y-%m-%d %H:%M:%S", os.time())
print(d2)
[root@netkiller lua]# lua date.lua 
2022-12-08 19:12:11
2022-12-08 19:12:11

3.2.3. 数据结构

3.2.3.1. list 列表

                 
[root@netkiller lua]# cat list.lua
local fruits = { "apple", "orange", "pear", "banana" }
for _, fruit in pairs(fruits) do
    if fruit == "pear" then
        print("We Found it!")
    else
        print("Oh no, keep traversing!")
    end
end

[root@netkiller lua]# lua list.lua
Oh no, keep traversing!
Oh no, keep traversing!
We Found it!
Oh no, keep traversing!

3.2.4. echo 输出

            
location /a {
	echo "A";
}        

location /b {
        echo "B";
}

3.2.5. 参数处理

3.2.5.1. 获取 GET/POST 参数

                
	location /param {
       content_by_lua_block {
           local arg = ngx.req.get_uri_args()
           for k,v in pairs(arg) do
               ngx.say("[GET ] key:", k, " value:", v)
           end

           ngx.req.read_body()
           local arg = ngx.req.get_post_args()
           for k,v in pairs(arg) do
               ngx.say("[POST] key:", k, " value:", v)
           end
       }
   }			
			
            
                
[root@netkiller nginx]# curl 'http://www.netkiller.cn/param?id=111&name=neo&nickname=netkiller'
[GET ] key:nickname value:netkiller
[GET ] key:name value:neo
[GET ] key:id value:111
			
            

                
[root@netkiller nginx]# curl http://www.netkiller.cn/param -d 'name=Neo&nickname=netkiller'
[POST] key:nickname value:netkiller
[POST] key:name value:Neo

3.2.5.2. 获取 body 数据

                
		lua_need_request_body on;
        location /body {
            content_by_lua_block {
                local data = ngx.req.get_body_data()
                ngx.say("body: ", data)
            }
        }		
		
            

                
[root@netkiller openresty]# bin/openresty -s reload

[root@netkiller openresty]# curl http://www.netkiller.cn/body -d Hello
body: Hello

[root@netkiller openresty]# curl http://www.netkiller.cn/body -d name=neo
body: name=neo

[root@netkiller openresty]# curl http://www.netkiller.cn/body -d "{\"status\":true}"
body: {"status":true}

3.2.5.3. 删除不需要的 GET 参数

需求如下，我们需要删除两个参数 password 跟 accesskey 

                
location = /test {
	rewrite_by_lua '
		local args = ngx.req.get_uri_args()
		args.password= nil
		args.accesskey = nil
		ngx.req.set_uri_args(args)
	';

	echo $args;
}

测试效果

                
[root@netkiller ~]# curl 'http://localhost/test?username=netkiller&password=123456&accesskey=112233&name=Neo&city=Shenzhen'a
username=netkiller&name=Neo&city=Shenzhena

我们可以看到两个参数已经被干掉。

3.2.6. Nginx 变量

3.2.6.1. 访问变量

ngx.var.[variable]

                
        location /test {
            set $name 'chen';

            content_by_lua_block {
                ngx.say("Name: ",ngx.var.name)
            }
        }

3.2.6.2. set_by_lua 拼接字符串变量

                
localtion ^~ /static/ { 

   set_by_lua $domain 'return "https://"..os.getenv("ENV")..".netkiller.cn"'; 
   proxy_pass $domain/resource$request_uri;

}

3.2.6.3. 从 lua 文件设置变量

set_by_lua_file

                
        location /proxy {
            set_by_lua_file $name lua/test.lua;

            content_by_lua_block {
                ngx.say("Name: ", ngx.var.name)
            }
        }			
			
            
                
[root@netkiller openresty]# cat nginx/lua/test.lua 
#!/usr/bin/env lua

return "Netkiller";

3.2.7. Json

3.2.7.1. 解码 json

                
location /json {
	content_by_lua_block {
		local cjson = require("cjson");
        local json_text = '{"foo":"bar"}'
        local data = cjson.decode(json_text)
        ngx.say("foo: ", data["foo"])
	}

}

剥离一层数组，注意第一个元素下标是1，不是0

                
local cjson = require("cjson");
local json_text = '[{"foo":"bar"}]'
local data = cjson.decode(json_text)
ngx.say("foo: ", data[1]["foo"])

3.2.8. Redis

            
local redisClient = require("resty.redis");
local redis = redisClient:new();
local ip = "127.0.0.1";
local port = 6379;
local ok,err = redis:connect(ip,port);		
if not ok then
    log.local_println("redis","Cannot connect, host: " .. ip .. ", port: " .. port)
    return nil, err
end;

local ok,err = redis:get("key");
if not ok then
   ngx.say("get key err",err);
   return;
else
	ngx.say(ok);
end;
		
        
            
location /redis {
	content_by_lua_block {
		local redisClient = require("resty.redis");
		local redis = redisClient:new();
		local ip = "127.0.0.1";
		local port = 6379;
		local ok,err = redis:connect(ip,port);
		if not ok then
		    log.local_println("redis","Cannot connect, host: " .. ip .. ", port: " .. port)
		    return nil, err
		end;
		
		local ok,err = redis:get("key");
		if not ok then
		   ngx.say("get key err",err);
		   return;
		else
		        ngx.say(ok);
		end;
	}
}

测试

            
[root@netkiller openresty]# redis-cli 
127.0.0.1:6379> set key Helloworld!!!
OK
127.0.0.1:6379> exit

[root@netkiller openresty]# curl http://www.netkiller.cn/redis
Helloworld!!!

3.2.9. Nginx 缓存

            
lua_shared_dict my_cache 128m;
server {
	listen 8080;
	location /cache {
	
		content_by_lua_block {
			local cache = ngx.shared.my_cache
			local key = 'nickname'
			local value ='netkiller'
			local exptime  = 0

			local result = cache:get(key)
			if not result then
			        local succ, err, forcible = cache:set(key, value, exptime)
			        ngx.say("set", succ)
			else
			        ngx.say("Value: ".. result)
			end;
		}
	}		
}

3.2.10. logs

在 server 下面增加 error_log 配置，这里只记录 notice

            
server {
    listen 8080;
	error_log logs/lua.log notice;

打印日志

            
ngx.log(ngx.NOTICE, "det: ", json_string)

日志输出

            
2022/08/04 13:58:52 [notice] 830752#0: *247 [lua] content_by_lua(nginx.conf:159):18: get: {"key":"platfrom","status":false,"value":""}, client: 127.0.0.1, server: , request: "GET /grey/get?key=platfrom HTTP/1.1", host: "localhost:8080"
2022/08/04 13:58:55 [notice] 830752#0: *248 [lua] content_by_lua(nginx.conf:185):22: set: {"exptime":0,"key":"platfrom","status":true,"value":"111"}, client: 127.0.0.1, server: , request: "GET /grey/set?key=platfrom&value=111 HTTP/1.1", host: "localhost:8080"
2022/08/04 13:58:59 [notice] 830752#0: *249 [lua] content_by_lua(nginx.conf:203):13: det: {"status":true,"key":"platfrom"}, client: 127.0.0.1, server: , request: "GET /grey/del?key=platfrom HTTP/1.1", host: "localhost:8080"		
		
        
            
日志级别： 
ngx.STDERR 标准输出 
ngx.EMERG 紧急报错 
ngx.ALERT 报警 
ngx.CRIT 严重，系统故障， 触发运维告警系统 
ngx.ERR 错误，业务不可恢复性错误 
ngx.WARN 提醒， 业务中可忽略错误 
ngx.NOTICE 提醒， 业务中比较重要信息 
ngx.INFO 信息， 业务琐碎日志信息， 包含不同情况判断等 
ngx.DEBUG 调试
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第 3 章 Openresty 起始页 3.3. 实现灰度发布