使用APISIX解析jwt并获取payload信息

APISIX支持获取jwt的信息，并且将这个信息进行解码并转发给后端服务。

1. 启动服务

首先我们根据官方脚本来启动APISIX服务

~ curl -sL "https://run.api7.ai/apisix/quickstart" | shDestroying existing apisix-quickstart container, if any.Installing APISIX with the quickstart options.Creating bridge network apisix-quickstart-net.77e35df073894075ad77facd9d1c7d2a35b280213732c1b631052caede079bab✔ network apisix-quickstart-net createdStarting the container etcd-quickstart.d123605c8b7658b130be97e5f44e7a160aa85858db008032ecf594266225e342✔ etcd is listening on etcd-quickstart:2379Starting the container apisix-quickstart.38434806c63b3a72f53fb6ad849cb4c11781eebaff79c8db04510226593fcf46⚠ WARNING: The Admin API key is currently disabled. You should turn on admin_key_required and set a strong Admin API key in production for security.✔ APISIX is ready!

2. 配置插件

启动了APISIX之后，我们首先创建一个插件配置。在这个插件中我们定义了一个Lua方法，这个方法的目的是从请求的header中获取authorization信息，并进行解码，之后将解码的信息放到HTTP header中传给后端

curl --location --request PUT 'http://127.0.0.1:9180/apisix/admin/plugin_configs/1001' \--header 'Content-Type: application/json' \--header 'Accept: */*' \--header 'Host: 127.0.0.1:9180' \--header 'Connection: keep-alive' \--data-raw '{    "plugins": {        "serverless-pre-function": {            "phase": "access",            "functions": [                "return function(_, ctx) local core = require(\"apisix.core\") local jwt = require(\"resty.jwt\") local auth_header = ctx.var.http_authorization if not auth_header then return end local token = auth_header:match(\"Bearer%s+(.+)\") if not token then return end local obj = jwt:load_jwt(token) if obj and obj.valid and obj.payload then if obj.payload.user_id then core.request.set_header(\"X-User-Id\", obj.payload.user_id) end if obj.payload.role then core.request.set_header(\"X-User-Role\", obj.payload.role) end end end"            ]        }    }}'

如上的fucntions属性中添加了一个Lua方法，格式化之后的Lua代码如下

return function(_, ctx)
  local core = require("apisix.core")
  local jwt = require("resty.jwt")

  local auth_header = ctx.var.http_authorization
  if not auth_header then
    return
  end

  local token = auth_header:match("Bearer%s+(.+)")
  if not token then
    return
  end

  local obj = jwt:load_jwt(token)
  if obj and obj.valid and obj.payload then
    if obj.payload.user_id then
      core.request.set_header("X-User-Id", obj.payload.user_id)
    end
    if obj.payload.role then
      core.request.set_header("X-User-Role", obj.payload.role)
    end
  end
end

这段代码实现了如下几个功能：

从 Authorization: Bearer 中提取 JWT
使用 resty.jwt 解码
如果合法，提取 user_id 和 role
注入到 header（X-User-Id, X-User-Role）中供后端读取

3. 配置consumer

创建了这个插件之后，我们再新建一个consumer。在APISIX中，consumer代表了一类客户端，比如APP。我们可以针对这类客户端添加一些配置，多种不同类型的客户端（比如APP、网页、开放平台，等等）可以分别设置成不同的consumer以方便管理

curl --location --request PUT 'http://127.0.0.1:9180/apisix/admin/consumers/app' \--header 'Content-Type: application/json' \--header 'Accept: */*' \--header 'Host: 127.0.0.1:9180' \--header 'Connection: keep-alive' \--data-raw '{    "username": "app",    "plugins": {        "jwt-auth": {            "key": "app-key",            "secret": "a-string-secret-at-least-256-bits-long",            "algorithm": "HS256"        }    }}'

如上添加了一个名为app的consumer，它的key是app-key，加密方式是HS256，密钥是a-string-secret-at-least-256-bits-long。有了解析插件和consumer之后，我们就可以创建路由了。

4. 配置路由

如下请求会创建一个ID为1的路由，使用了ID为1001插件，并且添加了jwt-auth的配置，路由的后端是https://httpbin.org，这个网站会把我们请求的信息返回给我们。

curl --location --request PUT 'http://127.0.0.1:9180/apisix/admin/routes/1' \--header 'Content-Type: application/json' \--header 'Accept: */*' \--header 'Host: 127.0.0.1:9180' \--header 'Connection: keep-alive' \--data-raw '{    "uri": "/headers",    "plugin_config_id": 1001,    "plugins": {        "jwt-auth": {}    },    "upstream": {        "type": "roundrobin",        "nodes": {            "httpbin.org:80": 1        }    }}'

5. 发起请求

在创建好了plugin_config、consumer和route之后，我们就可以测试请求了。首先我们构建如下payload

{
    "key": "app-key",
    "user_id": 100001,
    "role": "admin",
    "exp": 1900000000
}

这个payload包含了user_id和role两个业务属性，exp代表这个jwt的过期时间戳，key是APISIX用于识别匹配哪个consumer的，这里我们选择匹配app-key这个consumer。之后我们将该payload和密钥a-string-secret-at-least-256-bits-long一起在https://jwt.io/进行编码，得到编码jwt信息如下

eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJrZXkiOiJhcHAta2V5IiwidXNlcl9pZCI6MTAwMDAxLCJyb2xlIjoiYWRtaW4iLCJleHAiOjE5MDAwMDAwMDB9.qG7PNPz2XlatmjrhNW_xf6SmI8T9JSIx2lJVJcAox0I

之后我们执行HTTP请求，将这个jwt放到Authorization header中

curl --location --request GET 'http://127.0.0.1:9080/headers' \--header 'Authorization: Bearer eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJrZXkiOiJhcHAta2V5IiwidXNlcl9pZCI6MTAwMDAxLCJyb2xlIjoiYWRtaW4iLCJleHAiOjE5MDAwMDAwMDB9.qG7PNPz2XlatmjrhNW_xf6SmI8T9JSIx2lJVJcAox0I' \--header 'Accept: */*' \--header 'Host: httpbin.org:80' \--header 'Connection: keep-alive'

请求得到的响应如下，可以看到user_id和role属性已经成功的传给后端服务了

{
  "headers": {
    "Accept": "*/*",
    "Authorization": "Bearer eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJrZXkiOiJhcHAta2V5IiwidXNlcl9pZCI6MTAwMDAxLCJyb2xlIjoiYWRtaW4iLCJleHAiOjE5MDAwMDAwMDB9.qG7PNPz2XlatmjrhNW_xf6SmI8T9JSIx2lJVJcAox0I",
    "Host": "httpbin.org",
    "User-Agent": "curl/7.81.0",
    "X-Amzn-Trace-Id": "Root=1-68709903-309891501348175943af3223",
    "X-Consumer-Username": "app",
    "X-Forwarded-Host": "httpbin.org",
    "X-User-Id": "100001",
    "X-User-Role": "admin"
  }
}

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