1、此文章主要介绍内容

本文主要介绍如何利用Nginx lua 实现将阿里云OSS存储空间做到同本地磁盘一样使用。核心是利用Nginx lua 对OSS请求进行签名并利用内部跳转将所有访问本地Nginx的请求加上OSS 签名转发给OSS，实现本地Nginx无缝衔接阿里云OSS，存储空间无限扩展，存储成本无限下降，数据安全%99.99...... 。

2、本篇文章使用到的一些工具技术及如何学习和获取

1、lua

本文用到的都是一些基本的lua，基本上花半小时阅读下lua的语法就可以轻松理解本文内容

2、Nginx lua

主要是学习nginx lua 及环境部署，不过阅读本文还不需要亲自动手去学习及部署nginx lua 环境，读者可以从docker 官方镜像源pull openresty 镜像进行实验。本文已openresty/1.7.7.2 作为实验环境。

3、阿里云OSS

赶紧开通吧，用起来相当爽，一处存储全球无限制访问

https://www.aliyun.com/act/aliyun/ossdoc.html

4、参考博客

建议阅读我的另外一篇博客，对深入理解OSS 及互联网上提供的HTTP服务有更深刻的理解

https://yq.aliyun.com/articles/7511?spm=0.0.0.0.IWbHSR

3、利用Nginx lua 实现请求签名并转发至OSS

Lua 签名 code

注：此代码并非出自作者之手

oss_auth.lua

-- has been sorted in alphabetical order

local signed_subresources = {

   'acl',

   'append',

   'bucketInfo',

   'cname',

   'commitTransition',

   'comp',

   'cors',

   'delete',

   'lifecycle',

   'location',

   'logging',

   'mime',

   'notification',

   'objectInfo',

   'objectMeta',

   'partData',

   'partInfo',

   'partNumber',

   'policy',

   'position',

   'referer',

   'replication',

   'replicationLocation',

   'replicationProgress',

   'requestPayment',

   'response-cache-control',

   'response-content-disposition',

   'response-content-encoding',

   'response-content-language',

   'response-content-type',

   'response-expires',

   'restore',

   'security-token',

   'tagging',

   'torrent',

   'uploadId',

   'uploads',

   'versionId',

   'versioning',

   'versions',

   'website'

}

function string.startswith(s, start)

   return string.sub(s, 1, string.len(start)) == start

end

local function get_canon_sub_resource()

   local args = ngx.req.get_uri_args()

   -- lower keys

   local keys = {}

   for k, v in pairs(args) do

      keys[k:lower()] = v

   end

   -- make resource string

   local s = ''

   local sep = '?'

   for i, k in ipairs(signed_subresources) do

      v = keys[k]

      if v then

         -- sub table

         v = type(v) == 'table' and v[1] or v

         s = s .. string.format("%s%s=%s", sep, k, v)

         sep = '&'

      end

   end

   return s

end

local function get_canon_resource()

   resource = ''

   object = ngx.unescape_uri(ngx.var.uri)

   sub = get_canon_sub_resource()

   return string.format("/%s%s%s", ngx.var.oss_bucket, object, sub)

end   

local function get_canon_headers()

   -- default: <lowerkey, value>

   local headers = ngx.req.get_headers()

   local keys = {}

   for k, v in pairs(headers) do

      if string.startswith(k, 'x-oss-') then

         -- client must assemble the same header keys

         if type(v) ~= 'string' then return nil end

         table.insert(keys, k)

      end

   end

   -- sorted in alphabetical order

   table.sort(keys)

   for i, key in ipairs(keys) do

      keys[i] = key .. ':' .. headers[key] .. '\n'

   end

   return table.concat(keys)

end

local function calc_sign(key, method, md5, type_, date, oss_headers, resource)

    -- string_to_sign:

    -- method + '\n' + content_md5 + '\n' + content_type + '\n'

    -- + date + '\n' + canonicalized_oss_headers + canonicalized_resource

    local sign_str = string.format('%s\n%s\n%s\n%s\n%s%s',

    method, md5, type_,

    date, oss_headers, resource)

    ngx.log(ngx.ERR, "SignStr:", sign_str, "\n")

    local sign_result = ngx.encode_base64(ngx.hmac_sha1(key, sign_str))

    return sign_result, sign_str

end   

local function oss_auth()

   -- ngx.log(ngx.INFO, 'auth')

   --local method = ngx.var.request_method

   local method = ngx.req.get_method()

   local content_md5 = ngx.var.http_content_md5 or ''

   local content_type = ngx.var.http_content_type or ''

   -- get date

   local date = ngx.var.http_x_oss_date or ngx.var.http_date or ''

   if date == '' then

      date = ngx.http_time(ngx.time())

      -- ngx.log(ngx.INFO, 'Date:', date)

      ngx.req.set_header('Date', date)

   end

   local resource = get_canon_resource()

   local canon_headers = get_canon_headers()

   local sign_result, sign_str = calc_sign(ngx.var.oss_auth_key, method, content_md5,

   content_type, date, canon_headers, resource)

   -- ngx.log(ngx.INFO, 'sign string:', sign_str)

   -- ngx.log(ngx.INFO, 'sign string len:', string.len(sign_str))

   local auth = string.format("OSS %s:%s", ngx.var.oss_auth_id, sign_result)

   ngx.req.set_header('Authorization', auth)

   ngx.exec("@oss")

end   

-- main

res = oss_auth()

if res then

   ngx.exit(res)

end

nginx.conf

server {

    listen 8000;

    proxy_http_version 1.1;

    proxy_buffering off;

    proxy_request_buffering off;

    location / {

        set $oss_bucket "your_oss_bucket";

        set $oss_auth_id "your_access_id";

        set $oss_auth_key "your_access_key";

        rewrite_by_lua_file "/path/oss_auth.lua";

    }

    # internal redirect

    location @oss {

        // endpoint eg: oss.aliyuncs.com

        proxy_pass http://your_oss_bucket.endpoint;

    }

}

、如何使用上述代码

首先oss_auth.lua 无需做任何改动

nginx.conf 中需要将

your_oss_bucket 替换为阿里云OSS 的bucket名

your_access_id替换未AccessKeyId

your_access_key 替换为 AccessKeySecret

例如：

error_log  logs/error.log  debug;

events {

    worker_connections  1024;

}

http {

    include       mime.types;

    lua_package_path "/usr/servers/lualib/?.lua;";

    lua_package_cpath "/usr/servers/lualib/?.so;";

    server {

        listen       80；

        location / {

            set $oss_bucket "bucket-example";

            set $oss_auth_id "za2127hbbdsdjhkhskel0ytocbzr";

            set $oss_auth_key "gMOG3o+JHDSJHCNMcsaH+Q=";

            rewrite_by_lua_file conf/lua/oss_auth.lua;

        }

        location @oss {

            proxy_pass http://bucket-example.oss-cn-qingdao.aliyuncs.com;

        }

    }

}