验证AWS API网关的请求路径参数？

假设我有一个带有路径的 api/ and /{pets} and /{pets}/pet。现在我正在尝试验证路径{pets}参数，以便只有长度为 6 的字母数字字符的路径才会被验证并处理到后端 lambda，所有其他路径都将被拒绝。我尝试了以下 swagger 模式，指定参数的格式和类型。我什至尝试在架构中使用模式，但它似乎不起作用。我想知道如何才能仅限制某些 ID 的路径参数。

{
  ......
  "/{pets}/pet": {
      "get": {
          "consumes": [
              "application/json"
          ],
          "produces": [
              "application/json"
          ],
          "parameters": [{
              "name": "pets",
              "in": "path",
              "required": true,
              "schema": {
                  "type": "string",
                  "pattern": "[A-Za-z0-9]{6}"
              }
          }],
          "responses": {
              "200": {
                  "description": "200 response",
                  "schema": {
                      "$ref": "#/definitions/Empty"
                  }
              }
          },
          "x-amazon-apigateway-request-validator": "Validate query string parameters and headers",
          "x-amazon-apigateway-integration": {
              "responses": {
                  "default": {
                      "statusCode": "200"
                  }
              },
              "requestTemplates": {
                  "application/json": "##  See ...."
              },
              "uri": "........",
              "passthroughBehavior": "when_no_templates",
              "httpMethod": "POST",
              "contentHandling": "CONVERT_TO_TEXT",
              "type": "aws"
          }
      }
  }
  .....
}

我想要实现的目标：

https://api.example.com/aacc77/pet -- Accept
https://api.example.com/aacc77s/pet -- Reject
https://api.example.com/aacc7/pet -- Reject
https://api.example.com/aacc_7/pet -- Reject

基本上，我想使用这个正则表达式模式作为路径[A-Za-z0-9]{6}.

"pets": {
  "$schema": "http://json-schema.org/draft-04/schema#",
  "title": "Pets Schema",
  "type": "string",
  "pattern": "[A-Za-z0-9]{6}"
}

我看到有一个相关的问题here，我想知道是否有解决方案可用。