AWS Lambda - Java 个豆类

AWS Lambda - Java Beans

我有一个如下所示的请求:

package pricing

import scala.beans.BeanProperty

class Request(@BeanProperty var name: String, @BeanProperty var surname: String) {
  def this() = this(name="defName", surname="defSurname")
}

处理程序如下:

package pricing

import com.amazonaws.services.lambda.runtime.{Context, RequestHandler}
import scala.collection.JavaConverters
import spray.json._


class ApiGatewayHandler extends RequestHandler[Request, ApiGatewayResponse] {

  import DefaultJsonProtocol._

  def handleRequest(input: Request, context: Context): ApiGatewayResponse = {
    val headers = Map("x-foo" -> "coucou")
    val msg = "Hello " + input.name
    val message = Map[String, String]("message" -> msg )
    ApiGatewayResponse(
      200,
      message.toJson.toString(),
      JavaConverters.mapAsJavaMap[String, Object](headers),
      true
    )
  }
}

已记录为:

functions:
  pricing:
    handler: pricing.ApiGatewayHandler
    events:
      - http:
          path: pricing/test
          method: get
          documentation:
            summary: "submit your name and surname, the API says hi"
            description: ".. well, the summary is pretty exhaustive"
            requestBody:
              description: "Send over name and surname"
            queryParams:
              - name: "name"
                description: "your 1st name"
              - name: "surname"
                description: ".. guess .. "
            methodResponses:
              - statusCode: "200"
                responseHeaders:
                  - name: "x-foo"
                    description: "you can foo in here"
                responseBody:
                  description: "You'll see a funny message here"
                responseModels:
                  "application/json": "HelloWorldResponse"

好吧,这是其中一个教程的复制和粘贴。它不起作用。 我猜 BeanProperty 指的是 body 对象属性;这就是我从示例 here.

中可以猜到的

如果我想要查询字符串?

一个尝试是:

package pricing

import scala.beans.BeanProperty
import spray.json._

abstract class ApiGatewayGetRequest(
                                     @BeanProperty httpMethod: String,
                                     @BeanProperty headers: Map[String, String],
                                     @BeanProperty queryStringParameters: Map[String, String])


abstract class ApiGatewayPostRequest(
                                     @BeanProperty httpMethod: String,
                                     @BeanProperty headers: Map[String, String],
                                     @BeanProperty queryStringParameters: Map[String, String])

class HelloWorldRequest(
                         @BeanProperty httpMethod: String,
                         @BeanProperty headers: Map[String, String],
                         @BeanProperty queryStringParameters: Map[String, String]
                       ) extends ApiGatewayGetRequest(httpMethod, headers, queryStringParameters) {

  private def getParam(param: String): String =
    queryStringParameters get param match {
      case Some(s) => s
      case None => "default_" + param
    }

  def name: String = getParam("name")
  def surname: String = getParam("surname")

  def this() = this("GET", Map.empty, Map.empty)

}

这导致:

 {
  "message":"Hello default_name"
 }

建议 class 已用空地图代替 queryStringParameters 初始化,但已正确提交

 Mon Sep 25 20:45:22 UTC 2017 : Endpoint request body after
 transformations:
 {"resource":"/pricing/test","path":"/pricing/test","httpMethod":"GET","headers":null,"queryStringParameters":{"name":"ciao", "surname":"bonjour"},"pathParameters":null,"stageVariables":null,
 ...

注意: 我走这条路是因为我觉得用类型 T 替换 @BeanProperty queryStringParameters: Map[String, String] 中的 Map 会方便且富有表现力,例如

case class Person(@beanProperty val name: String, @beanProperty val surname: String)

但是,上面的代码将 {"name":"ciao", "surname":"bonjour"} 视为 String,但没有弄清楚它应该反序列化该字符串。

编辑

我也尝试用 java.util.Map[String, String] 替换 scala 映射但没有成功

默认情况下,Serverless 启用 proxy integration between the lambda and API Gateway。这对您来说意味着 API Gateway 将把一个包含关于请求的所有元数据的对象传递给您的处理程序,正如您已经注意到的:

Mon Sep 25 20:45:22 UTC 2017 : Endpoint request body after transformations: {"resource":"/pricing/test","path":"/pricing/test","httpMethod":"GET","headers":null,"queryStringParameters":{"name":"ciao", "surname":"bonjour"},"pathParameters":null,"stageVariables":null, ...

这显然不会映射到您的模型,其中只有字段 namesurname。有几种方法可以解决这个问题。

1。调整您的模型

如果您通过使字段可变(并因此为它们创建设置器)使 class 成为合适的 POJO,您对 HelloWorldRequest class 的尝试确实有效:

class HelloWorldRequest(
                         @BeanProperty var httpMethod: String,
                         @BeanProperty var headers: java.util.Map[String, String],
                         @BeanProperty var queryStringParameters: java.util.Map[String, String]
                       ) extends ApiGatewayGetRequest(httpMethod, headers, queryStringParameters) {

AWS Lambda 文档states:

The get and set methods are required in order for the POJOs to work with AWS Lambda's built in JSON serializer.

另请注意,不支持 Scala 的 Map。

2。使用自定义请求模板

如果您不需要元数据,那么您可以使用 mapping templates.

让 API 网关仅将您需要的数据传递到 lambda 中,而不是更改您的模型

为此,您需要告诉 Serverless 使用普通的 lambda 集成(而不是代理)和 specify a custom request template

Amazon API 网关文档有 an example request template 几乎可以完美解决您的问题。稍微调整一下,我们得到

functions:
  pricing:
    handler: pricing.ApiGatewayHandler
    events:
      - http:
          path: pricing/test
          method: get
          integration: lambda
          request:
            template:
              application/json: |
                #set($params = $input.params().querystring)
                {
                #foreach($paramName in $params.keySet())
                  "$paramName" : "$util.escapeJavaScript($params.get($paramName))"
                  #if($foreach.hasNext),#end
                #end
                }

此模板将从查询字符串参数中生成 JSON,现在它将成为 lambda 的输入:

Endpoint request body after transformations: { "name" : "ciao" }

哪个正确映射到您的模型。

请注意,禁用代理集成也会更改响应格式。您会注意到现在您的 API return 直接是您的响应模型:

{"statusCode":200,"body":"{\"message\":\"Hello ciao\"}","headers":{"x-foo":"coucou"},"base64Encoded":true}

您可以通过将代码修改为仅 return 正文或添加自定义响应模板来解决此问题:

          response:
            template: $input.path('$.body')

这会将输出转换为您所期望的,但会公然忽略 statusCodeheaders。您将需要进行更复杂的响应配置来处理这些问题。

3。自己做映射

而不是扩展 RequestHandler 并让 AWS Lambda 将 JSON 映射到 POJO,you can instead extend RequestStreamHandler,这将为您提供 InputStreamOutputStream,因此您可以使用您选择的 JSON 序列化程序进行(反)序列化。