摘要：用于方便地搭建能够处理超高并发扩展性极高的动态应用服务和动态网关。

权限认证是接口开发中不可避免的问题,权限认证包括两个方面

接口需要知道调用的用户是谁

接口需要知道该用户是否有权限调用

第1个问题偏向于架构，第2个问题更偏向于业务，因此考虑在架构层解决第1个问题，以达到以下目的

所有请求被保护的接口保证是合法的(已经认证过的用户)

接口可以从请求头中获取当前用户信息

每个请求都有uuid用于标识

JWT(JSON Web Token)目前是应用最广的接口权限方案，具有无状态,跨系统,多语言多平台支持等特点，如果能在网关层实现JWT验证不仅可以避免代码入侵还能为整个后台提供统一的解决方案,目前客户网关使用Nginx,但社区版Nginx中没有JWT模块,自己实现不现实,因此选择OpenResty作为网关层, 据官网介绍,OpenResty® 是一个基于 Nginx 与 Lua 的高性能 Web 平台，其内部集成了大量精良的 Lua 库、第三方模块以及大多数的依赖项。用于方便地搭建能够处理超高并发、扩展性极高的动态 Web 应用、Web 服务和动态网关。本质上就是一个Nginx+Lua的集成软件.
整体架构如图：

[root@docker ~]# cat /etc/redhat-release
CentOS Linux release 7.4.1708 (Core)
[root@docker ~]# more /proc/version
Linux version 3.10.0-693.el7.x86_64 (builder@kbuilder.dev.centos.org) (gcc version 4.8.5 20150623 (Red Hat 4.
8.5-16) (GCC) ) #1 SMP Tue Aug 22 21:09:27 UTC 2017

OpenRestry安装很简单,可以在这里找到不同版本操作系统安装文档,本次使用的环境是CentOS Linux release 7.4

[root@docker ~]# yum install yum-utils
[root@docker ~]# yum-config-manager --add-repo https://openresty.org/package/centos/openresty.repo
[root@docker ~]# yum install openresty
[root@docker ~]# yum install openresty-resty

系统默认安装在/usr/local/openresty/目录下,版本如下

[root@docker openresty]# cd /usr/local/openresty/bin/
[root@docker bin]# ./openresty -v
nginx version: openresty/1.13.6.2

可以将OpenResty目录加到PATH里，方便使用.

修改nginx.conf文件测试是否安装成功

tee /usr/local/openresty/nginx/conf/nginx.conf <<-"EOF"
worker_processes  1;
error_log logs/error.log;
events {
    worker_connections 1024;
}
http {
    server {
        listen 8080;
        location / {
            default_type text/html;
            content_by_lua "
                ngx.say("
hello, world
")
            ";
        }
    }
}
EOF
[root@docker conf]# openresty -s reload
[root@docker conf]# curl localhost:8080
hello, world

这里使用JWT官方推荐Lua实现库,项目地址为https://github.com/SkyLothar/...,有趣的是,这个项目的介绍是这么写的JWT For The Great Openresty,看来是为OpenResty量身定做.github上有安装教程,但一方面有些第三方库的安装文档没有提及,另一方面有些内容没有用到安装的时候可以跳过,这里将完整安装步骤重新整理了下.

在release页面https://github.com/SkyLothar/...下载项目源码,截止到目前最新版为v0.1.11

下载hmac源码,截止到目前项目还未release,只能下载项目里的源文件https://github.com/jkeys089/l...

在服务器创建目录/usr/local/openresty/nginx/jwt-lua/resty,将第1步压缩包中目录lua-resty-jwt-0.1.11/lib/resty/下的所有lua文件和第2步中的hmac.lua文件拷贝到该目录下,文件列表如下.

[root@docker resty]# pwd
/usr/local/openresty/nginx/jwt-lua/resty
[root@docker resty]# ll
total 60
-rwxr-xr-x. 1 root root 11592 Jul 18 10:40 evp.lua
-rw-r--r--. 1 root root  3796 Jul 18 10:40 hmac.lua
-rwxr-xr-x. 1 root root 27222 Jul 18 10:40 jwt.lua
-rwxr-xr-x. 1 root root 15257 Jul 18 10:40 jwt-validators.lua

修改nginx.conf验证是否生效

tee /usr/local/openresty/nginx/conf/nginx.conf <<-"EOF"
worker_processes  1;
error_log logs/error.log info;
events {
    worker_connections 1024;
}
http {
    lua_package_path "/usr/local/openresty/nginx/jwt-lua/?.lua;;";
    server {
        listen 8080;
        default_type text/plain;
        location = / {
            content_by_lua "
                local cjson = require "cjson"
                local jwt = require "resty.jwt"

                local jwt_token = "eyJ0eXAiOiJKV1QiLCJhbGciOiJIUzI1NiJ9" ..
                    ".eyJmb28iOiJiYXIifQ" ..
                    ".VAoRL1IU0nOguxURF2ZcKR0SGKE1gCbqwyh8u2MLAyY"
                local jwt_obj = jwt:verify("lua-resty-jwt", jwt_token)
                ngx.say(cjson.encode(jwt_obj))
            ";
        }
        location = /sign {
            content_by_lua "
                local cjson = require "cjson"
                local jwt = require "resty.jwt"

                local jwt_token = jwt:sign(
                    "lua-resty-jwt",
                    {
                        header={typ="JWT", alg="HS256"},
                        payload={foo="bar"}
                    }
                )
                ngx.say(jwt_token)
            ";
        }
    }
}
EOF

[root@docker resty]# curl localhost:8080
{"signature":"VAoRL1IU0nOguxURF2ZcKR0SGKE1gCbqwyh8u2MLAyY","reason":"everything is awesome~ :p","valid":true,"raw_header":"eyJ0eXAiOiJKV1QiLCJhbGciOiJIUzI1NiJ9","payload":{"foo":"bar"},"header":{"alg":"HS256","typ":"JWT"},"verified":true,"raw_payload":"eyJmb28iOiJiYXIifQ"}

验证通过,jwt模块安装完毕

上面jwt模块还无法用于生产环境,有几个问题没解决

jwt token目前是写死在配置文件里,生产需要从header Authorization中获取

验证失败目前返回是200生产需要返回401

需要配置反向代理并且将用户信息放在代理header上

local jwt = require "resty.jwt"
local cjson = require "cjson"
--your secret
local secret = "5pil6aOO5YaN576O5Lmf5q+U5LiN5LiK5bCP6ZuF55qE56yR"

local M = {}

function M.auth(claim_specs)
    -- require Authorization request header
    local auth_header = ngx.var.http_Authorization

    if auth_header == nil then
        ngx.log(ngx.WARN, "No Authorization header")
        ngx.exit(ngx.HTTP_UNAUTHORIZED)
    end

    ngx.log(ngx.INFO, "Authorization: " .. auth_header)

    -- require Bearer token
    local _, _, token = string.find(auth_header, "Bearer%s+(.+)")

    if token == nil then
        ngx.log(ngx.WARN, "Missing token")
        ngx.exit(ngx.HTTP_UNAUTHORIZED)
    end

    ngx.log(ngx.INFO, "Token: " .. token)

    local jwt_obj = jwt:verify(secret, token)
    if jwt_obj.verified == false then
        ngx.log(ngx.WARN, "Invalid token: ".. jwt_obj.reason)
        ngx.exit(ngx.HTTP_UNAUTHORIZED)
    end

    ngx.log(ngx.INFO, "JWT: " .. cjson.encode(jwt_obj))

    -- write the uid variable
    ngx.var.uid = jwt_obj.payload.sub
end

return M

worker_processes  1;
error_log logs/error.log info;
events {
    worker_connections 1024;
}
http {
    upstream tomcat{
     server localhost:80;
    }
    lua_package_path "/usr/local/openresty/nginx/jwt-lua/?.lua;;";
    server {
        listen 8080;
        set $uid "";
        location / {
            access_by_lua "
            local jwt = require("resty.nginx-jwt")
            jwt.auth()
        ";
            default_type application/json;
            proxy_set_header uid $uid;
            proxy_pass http://tomcat;
        }
    }
}

这里后台启动了一台tomcat并设置监听端口为80,tomcat上部署了一个示例的war包,代码逻辑较简单,就是输出所有的header,代码如下:

package asan.demo;
import java.io.IOException;
import java.io.PrintWriter;
import java.util.Enumeration;
import javax.servlet.*;
import javax.servlet.http.*;

public class JWTDemoService extends HttpServlet {
    private static final String CONTENT_TYPE = "text/html; charset=UTF-8";

    public void init(ServletConfig config) throws ServletException {
        super.init(config);
    }

    public void service(HttpServletRequest request,
                        HttpServletResponse response) throws ServletException,
                                                             IOException {
        response.setContentType(CONTENT_TYPE);
        PrintWriter out = response.getWriter();
        Enumeration em=request.getHeaderNames();
        while(em.hasMoreElements()){
            String key=(String)em.nextElement();
            String value=(String)request.getHeaders(key).nextElement();
            out.println(String.format("%s ==> %s", key,value));
        }
        out.close();
    }
}

重启OpenResty测试,如果没有指定jwt token信息返回401

[root@docker conf]# curl http://localhost:8080/jwtdemo/service



401 Authorization Required
openresty/1.13.6.2

指定jwt token

[root@docker conf]# curl -i http://localhost:8080/jwtdemo/ -H "Authorization: Bearer eyJ0eXAiOiJKV1QiLCJhbGciOiJIUzI1NiJ9.eyJqdGkiOiJ5YXlhIiwiaWF0IjoxNTMxODkyNzE3LCJpc3MiOiJ5YXlhIiwic3ViIjoieWF5YSIsImV4cCI6MTUzMTkyODcxN30.W5UXlwKHSrpUAYbfoF-fTBTS9Enm1wsvCKNQm0yLSfQ"
HTTP/1.1 200
Server: openresty/1.13.6.2
Date: Wed, 18 Jul 2018 05:52:13 GMT
Content-Type: text/html;charset=UTF-8
Content-Length: 298
Connection: keep-alive

uid ==> yaya
host ==> tomcat
connection ==> close
user-agent ==> curl/7.29.0
accept ==> */*
authorization ==> Bearer eyJ0eXAiOiJKV1QiLCJhbGciOiJIUzI1NiJ9.eyJqdGkiOiJ5YXlhIiwiaWF0IjoxNTMxODkyNzE3LCJpc3MiOiJ5YXlhIiwic3ViIjoieWF5YSIsImV4cCI6MTUzMTkyODcxN30.W5UXlwKHSrpUAYbfoF-fTBTS9Enm1wsvCKNQm0yLSfQ

从结果上看,后台服务已经获取到uid这个header
至于请求用到jwt token可以从任意平台生成只要保证secret一样即可,根据官网介绍,该库目前支持到jwt生成算法如图:

为每个请求生成唯一的uuid码可以将网关层上的请求和应用层的请求关联起来,对排查问题,接口统计都非常有用.

创建文件/usr/local/openresty/nginx/jwt-lua/resty/uuid.lua

local M  = {}
local charset = {}  do -- [0-9a-zA-Z]
    for c = 48, 57  do table.insert(charset, string.char(c)) end
    for c = 65, 90  do table.insert(charset, string.char(c)) end
    for c = 97, 122 do table.insert(charset, string.char(c)) end
end
function M.uuid(length)
        local res = ""
        for i = 1, length do
                res = res .. charset[math.random(1, #charset)]
        end
        return res
end
return M

修改配置文件nginx.conf

worker_processes  1;
error_log logs/error.log info;
events {
    worker_connections 1024;
}
http {
    upstream tomcat{
     server localhost:80;
    }
    lua_package_path "/usr/local/openresty/nginx/jwt-lua/?.lua;;";
    server {
        listen 8080;
        set $uid "";
        set $uuid "";
        location / {
            access_by_lua "
            local jwt = require("resty.nginx-jwt")
            jwt.auth()
            local u = require("resty.uuid")
            ngx.var.uuid = u.uuid(64)
        ";
            default_type application/json;
            proxy_set_header uid $uid;
            proxy_set_header uuid $uuid;
            proxy_pass http://tomcat;
        }
    }
}

重启OpenResty,测试

[root@docker conf]# openresty -s reload
[root@docker conf]# curl -i http://localhost:8080/jwtdemo/ -H "Authorization: Bearer eyJ0eXAiOiJKV1QiLCJhbGciOiJIUzI1NiJ9.eyJqdGkiOiJ5YXlhIiwiaWF0IjoxNTMxODk0MDA3LCJpc3MiOiJ5YXlhIiwic3ViIjoieWF5YSIsImV4cCI6MTUzMTkzMDAwN30.vQvpQpIHCmK5QBgIoRR8jhIGeYlHOMYySIr4gHvoZFE"
HTTP/1.1 200
Server: openresty/1.13.6.2
Date: Wed, 18 Jul 2018 08:05:45 GMT
Content-Type: text/html;charset=UTF-8
Content-Length: 372
Connection: keep-alive

uid ==> yaya
uuid ==> nhak5eLjQZ73yhAyHLTgZnSBeDa8pa1p3pcpBFvJ4Mv1fkY782UgVr8Islheq03l
host ==> tomcat
connection ==> close
user-agent ==> curl/7.29.0
accept ==> */*
authorization ==> Bearer eyJ0eXAiOiJKV1QiLCJhbGciOiJIUzI1NiJ9.eyJqdGkiOiJ5YXlhIiwiaWF0IjoxNTMxODk0MDA3LCJpc3MiOiJ5YXlhIiwic3ViIjoieWF5YSIsImV4cCI6MTUzMTkzMDAwN30.vQvpQpIHCmK5QBgIoRR8jhIGeYlHOMYySIr4gHvoZFE

可以看到,多了一个uuid的请求头

这里提供一个生成jwt token的java示例

package com.yaya;

import io.jsonwebtoken.JwtBuilder;
import io.jsonwebtoken.Jwts;
import io.jsonwebtoken.SignatureAlgorithm;
import javax.crypto.spec.SecretKeySpec;
import java.security.Key;
import java.util.Date;
import java.util.HashMap;
import java.util.Map;

/**
 * @Description:
 * @author: jianfeng.zheng
 * @since: 2018/7/5 下午9:56
 * @history: 1.2018/7/5 created by jianfeng.zheng
 */
public class JWTDemo {
    
    public static final String SECRET="5pil6aOO5YaN576O5Lmf5q+U5LiN5LiK5bCP6ZuF55qE56yR";
    
    public static String createJWT(String uid, long ttlMillis) throws Exception {
        SignatureAlgorithm signatureAlgorithm = SignatureAlgorithm.HS256;
        long nowMillis = System.currentTimeMillis();
        Date now = new Date(nowMillis);
        Key signingKey = new SecretKeySpec(SECRET.getBytes(), signatureAlgorithm.getJcaName());

        Map header=new HashMap();
        header.put("typ","JWT");
        header.put("alg","HS256");
        JwtBuilder builder = Jwts.builder().setId(uid)
                .setIssuedAt(now)
                .setIssuer(uid)
                .setSubject(uid)
                .setHeader(header)
                .signWith(signatureAlgorithm, signingKey);
        if (ttlMillis >= 0) {
            long expMillis = nowMillis + ttlMillis;
            Date exp = new Date(expMillis);
            builder.setExpiration(exp);
        }
        return builder.compact();
    }

    public static void main(String[]cmd) throws Exception {
        String s=createJWT("yaya",36000000);
        System.out.println("Bearer "+s);
    }

}

pom.xml

    4.0.0

    com.yaya
    jwtdemo
    1.0-SNAPSHOT
    
        
            io.jsonwebtoken
            jjwt
            0.6.0
        
    

这里只是解决了文章开头提到的第一个问题,接口需要知道是谁调用了接口,第二个问题,用户能不能调接口目前考虑用aop在应用层实现,后续也会继续更新.