OpenResty ngx 模块介绍

value = ngx.HTTP_OK (200)
value = ngx.HTTP_CREATED (201)
value = ngx.HTTP_ACCEPTED (202)
value = ngx.HTTP_BAD_REQUEST (400)
value = ngx.HTTP_UNAUTHORIZED (401)
value = ngx.HTTP_PAYMENT_REQUIRED (402) (first added in the v0.9.20 release)
value = ngx.HTTP_FORBIDDEN (403)
value = ngx.HTTP_NOT_FOUND (404)
value = ngx.HTTP_NOT_ALLOWED (405)
...

  location /sub {
    content_by_lua_block {
      ngx.say("sub pre: ", ngx.ctx.blah)
      ngx.ctx.blah = 32
      ngx.say("sub post: ", ngx.ctx.blah)
    }
  }

  location /main {
    content_by_lua_block {
      ngx.ctx.blah = 73
      ngx.say("main pre: ", ngx.ctx.blah)
      local res = ngx.location.capture("/sub")
      ngx.print(res.body)
      ngx.say("main post: ", ngx.ctx.blah)
    }
}

main pre: 73
sub pre: nil
sub post: 32
main post: 73

local capture = ngx.location.capture
local res = capture(uri,
    {method = ngx.HTTP_POST,
    args = { ... },
    body = "xxx"
    })

if res.status = ngx.HTTP_OK then
  ngx.print(res.body)
end
if res.status ~= ngx.HTTP_OK then
  ngx.exit(res.status)
end
if res.truncated then
  ngx.log(ngx.ERR, "xxx")
end

    location /test-log {
        content_by_lua_block {
          local i = "xxxx";
          ngx.log(ngx.ERR, "some error...", i);
          ngx.log(ngx.INFO, "some info...", i);
          ngx.log(ngx.DEBUG, "some debug...", i);
          ngx.say("log done");
        }
    }

$ curl '127.0.0.1/test-log'
log done

# error.log 日志
2022/09/11 09:25:29 [error] 2887#0: *13 [lua] content_by_lua(default.conf:57):3: some error...xxxx, client: 127.0.0.1, server: localhost, request: "GET /test-log HTTP/1.1", host: "127.0.0.1"

ngx.md5("strs")

ngx.req.read_body ()
local data = ngx.req.get_body_data()
if data then
  ngx.say('body: ', data)
else
  local name = ngx.req.get_body_file()
  local f = io.open(name, 'r')
  data = f:read('*a')
  f:close()
end

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

           ngx.req.read_body() -- 解析 body 参数之前一定要先读取 body
           local arg = ngx.req.get_post_args()
           for k,v in pairs(arg) do
               ngx.say("[POST] key:", k, " v:", v)
           end
       }
   }

   location /test-print-param {
       content_by_lua_block {
           local res = ngx.location.capture(
                '/print_param',
                {
                    method = ngx.HTTP_POST,
                    args = ngx.encode_args({a = 1, b = '2&'}),
                    body = ngx.encode_args({c = 3, d = '4&'})
                }
            )
           ngx.say(res.body)
       }
   }

# %26 是 & 符
$ curl '127.0.0.1/print_param?a=1&b=2%26' -d 'c=3&d=4%26'
[GET ] key:b v:2&
[GET ] key:a v:1
[POST] key:d v:4&
[POST] key:c v:3

# url 参数传递
$ curl '127.0.0.1/test-print-param'
[GET ] key:a v:1
[GET ] key:b v:2&
[POST] key:c v:3
[POST] key:d v:4&

location /proxy {
    internal;
    rewrite_by_lua_block {
        -- 获取原始请求的查询参数
        local args = ngx.req.get_uri_args()

        -- 添加新参数
        args["from"] = "nginx"

        -- 设置新的查询参数
        ngx.req.set_uri_args(args)

        -- 转发到目标地址
        ngx.exec("@target")
    }
}

location @target {
    proxy_pass http://backend_server;
}

# 或
location /api {
    rewrite_by_lua_block {
        -- 获取当前URI参数
        local args = ngx.req.get_uri_args()

        -- 添加新参数
        args.from = "nginx"

        -- 重新设置URI参数
        ngx.req.set_uri_args(args)
    }

    proxy_pass http://backend_server;
}

# 或
location /forward {
    content_by_lua_block {
        local http = require "resty.http"
        local httpc = http.new()

        -- 获取原始参数
        local args = ngx.req.get_uri_args()

        -- 添加新参数
        args.from = "nginx"

        -- 转发请求
        local res, err = httpc:request_uri("http://backend_server/api", {
            method = ngx.req.get_method(),
            args = args,
            headers = ngx.req.get_headers()
        })

        if not res then
            ngx.log(ngx.ERR, "request failed: ", err)
            ngx.exit(500)
        end

        -- 返回响应
        ngx.status = res.status
        for k, v in pairs(res.headers) do
            ngx.header[k] = v
        end
        ngx.print(res.body)
    }
}

http {
    server {
        listen    80;

        # ngx.req.read_body() 和 lua_need_request_body 必须配置一个，否则读不到数据
        # lua_need_request_body on;

        location /test-get-body-data {
            content_by_lua_block {
                ngx.req.read_body()
                local data = ngx.req.get_body_data()
                ngx.say("hello ", data)
            }
        }
    }
}

$ curl '127.0.0.1/test-get-body-data' -d 'world'
hello world

ngx.resp.get_headers(0, true)

-- 从 header 获取 ip
local headers=ngx.req.get_headers()
local ip = headers["X-REAL-IP"] or headers["X_FORWARDED_FOR"] or ngx.var.remote_addr or "0.0.0.0"

# 自定义 header
ngx.header.Foo = 'Bar'
-- Foo: Bar

-- _ 会自动转化为 -
ngx.header['Foo_Bar'] = {'a=123; path=/', 'b=4; path=/'}
-- Foo-Bar: a=123; path=/
-- Foo-Bar: b=4; path=/

# 删除 header
ngx.header["X-Header"] = nil;
ngx.header["X-Header"] = {};

-- curl -H "Foo: bar" 127.0.0.1:80/api/test_header
local function print_table(t)
  local function parse_array(key, tab)
    local str = ''
    for _, v in pairs(tab) do
      str = str .. key .. ' ' .. v .. '\r\n'
    end

    return str
  end

  local str = ''
  for k, v in pairs(t) do
    if type(v) == "table" then
      str = str .. parse_array(k, v)
    else
      str = str .. k .. ' ' .. (v) .. '\r\n'
    end
  end

  return str
end

-- local headers = ngx.req.get_headers()  -- 请求 Headers
local headers = ngx.resp.get_headers(0, true)  -- 响应 Headers
ngx.say(print_table(headers))

local semaphore = require "ngx.semaphore"
-- new 新建；wait 等待信号量；post 新增信号量；count 获取信号量数量

-- 初始资源数量，默认为 0
local sema = semaphore.new(0)

sema:post()
sema:wait(1)  -- 等待1s获取信号量
-- 配合共享内存实现数据传递

loca l shmem = ngx.shared.shmem
local ok, err, f

-- 设置
ok, err, f = shmem:set("num", 1, 0.05) -- 0.05 秒后过期
assert(ok and not f)

ok, err = shmem:add("num", 1)
assert (not ok)

ok, err = shmem:replace("num", 2)
assert (ok)

ok, err = shmem:add("ver", 1, 0, 1)
assert (ok)

-- 获取
local v , flags = shmem:get ("ver")
assert(v == 1 and flags == 1)
ngx.sleep(0.2)
local v, err, stale = shmem:get_stale("num")

-- 删除
shmem:delete("num")

-- 计数
local v = shmem:incr("count", 1, 0)
local v = shmem:incr("count", 5)

-- 队列操作
local len = shmem:lpush("list", "a")
local len = shmem:rpush("list", "z")
local len = shmem:llen("list")
local v = shmem:lpop("list")
local v = shmem:rpop("list")

local sock = ngx.socket.tcp()

-- sock:settimeout(1000)  -- 超时时间 1000 毫秒
-- sock:settimeouts(connect_time, send_timeout, read_time)

local ok, err = sock:connect("www.baidu.com", 80)
if not ok then
    ngx.say("failed to connect to baidu: ", err)
    return
end

-- 放入连接池，timeout 指定连接空闲时间，单位是毫秒；size 连接池大小
-- ok, err = sock:setkeepalive(timeout, size)

-- 获取复用次数
-- count, err = sock:getreusedtimes()

local req_data = "GET / HTTP/1.1\r\nHost: www.baidu.com\r\n\r\n"
-- 同步非阻塞发送数据
local bytes, err = sock:send(req_data)
if err then
    ngx.say("failed to send to baidu: ", err)
    return
end

-- 同步非阻塞接收数据，*a 表示接受所有数据
local data, err, partial = sock:receive("*a")
if err then
    ngx.say("failed to receive from baidu: ", err)
    return
end

-- 关闭连接
sock:close()
ngx.say("successfully talk to baidu! response first line: ", data)

local spawn = ngx.thread.spawn
local wait = ngx.thread.wait

local function sayhi(world)
  ngx.say("hi ", world)
end

-- 启动线程
-- t = spawn(func, arg1, arg2, ...)
local threads = {
  spawn(sayhi, "world"),
  spawn(sayhi, "world")
  spawn(sayhi, "world")
}

-- 等待线程
-- ok, ... = ngx.thread.wait(task1, task2, ...)
local ok, v = wait(unpack(threads))
for i, t in ipairs(threads) do
  local ok, v = wait(t)
  ngx.sya("wait ", v)
end

-- 获取所有协程对象
co = coroutine.running()
-- 挂起线程
coroutine.yield(co)

-- 停止线程
local kill = ngx.thread.kill
kill(t)

    init_worker_by_lua_block {
        local delay = 3  -- in seconds
        local timer_at = ngx.timer.at
        local log = ngx.log
        local ERR = ngx.ERR

        local task = function(premature, params)
            if premature then
                return
            end

            log(ERR, "run ...")
            new_timer(delay, task)  -- maybe need check result
        end

        if 1 == ngx.worker.id() then
            local ok, err = new_timer(delay, task)
            if not ok then
                log(ERR, "failed to create timer: ", err)
                return
            end
        end
    }

local names = upstream.get_upstreams()
for i, n = in ipairs(names) do
  local srvs , err = upstream.get_servers(n)
  if not srvs then
    ngx.say("failed to get servers in ", n)
    goto continue
  end
  ngx.say("upstream : "， n)
  for i,s in ipairs(srvs) do
    for k,v in pairs(s) do
      ngx.print(k, "=", v, ";")
    end
  end
  ::continue::
end

# 下线
upstream.set_peer_down(...)

upstream dyn backend { #动态上游集群
  server 0.0.0.0;  # 无实际意义的占位用
  balancer_by_lua_file proxy/balancer.lua;
  keepalive 10;
}

$ cat proxy/balancer.lua
local balancer = require "ngx.balancer"

local servers = {
  {"127.0.0.1", 80},
  {"127.0.0.1", 8080},
}

balancer.set_timeouts(1, 0.5, 0.5)
balancer.set_more_tries(2)

local n = math.random(#servers)

local ok, err = balancer.set_current_peer(servers[n][1], servers[n][2])
if not ok then
  ngx.log(ngx.ERR, "failed to set peer:", err)
 return ngx.exit(500)
end

location /foo {
    set $my_var ''; # this line is required to create $my_var at config time
    content_by_lua_block {
        ngx.var.my_var = 123
        ...
        // 删除变量
        ngx.var.my_var = nil
    }
}

init_by_lua 'key = os.getenv("KEY")'
...
server {
    set_by_lua $key 'return key';
    location /get {
        echo $key;
    }
}

local function cleanup()
  ngx.log(ngx.ERR, "something clean...")
  ngx.exit(400)
end

local ok, err = ngx.on_abort(cleanup)