openresty本身要发起http请求是一件比较麻烦的事情，还好有春哥写了个lua_resty_http，让openresty发起http请求更容易。

我使用的是其中一个分支：https://github.com/pintsized/lua-resty-http

git clone https://github.com/pintsized/lua-resty-http

下载到openresty安装的目录下后,接着在nginx.conf中添加lua文件的路径："/data/apiserver/lua-resty-http/lib/?.lua;;";

另外再添加一个location:

location /test {
    content_by_lua_file scripts/test.lua ;
}

再看test.lua文件：

ngx.header.content_type = "application/json;charset=UTF-8"
local json = require "cjson"
local http = require "resty.http"
local httpc = http:new()
local url = "http://api.xxxx.com/"
local res, err = httpc:request_uri(url, {
        method = "POST",
        body = "appid=20170412&secret=11111",
        -- query = {
        --         appid = "20170412", --填写自己的appid
        --         secret = "zbb", -- 填写自己的secret
        -- },
        ssl_verify = false, -- 需要关闭这项才能发起https请求
        headers = {["Content-Type"] = "application/x-www-form-urlencoded" },
      })
if not res then
        ngx.say("failed to request: ", err)
        return
end

ngx.say(json.encode({code=res.status,message=res.body}))