AWS SAM 将 cors 配置为在本地运行答案

【问题标题】：AWS SAM configure cors to run locallyAWS SAM 将 cors 配置为在本地运行
【发布时间】：2020-08-30 20:08:27
【问题描述】：

如何配置 cors 以在本地运行 lambda 函数

我尝试了不同的方法，但无法得到正确的解决方案。

下面是我的template.yml

Resources:
  MyApi:
    Type: AWS::Serverless::Api
    Properties:
      StageName: dev
      Cors:
        AllowHeaders: "'Content-Type,Authorization,Origin,X-Requested-With,Accept,x-id-token,x-custom-header'"
        AllowOrigin: "'*'"
        AllowMethods: "'OPTIONS,POST,GET,PUT,DELETE'"
        AllowCredentials: "'*'"
      Auth:
        AddDefaultAuthorizerToCorsPreflight: False
        DefaultAuthorizer: MyLambdaTokenAuthorizer
        Authorizers:
          MyLambdaTokenAuthorizer:
            FunctionArn: !GetAtt MyAuthFunction.Arn

  HelloFunction:
    Type: AWS::Serverless::Function
    Properties:
      Handler: functions/hello/handler.hello
      CodeUri: "."
      Events:
        HelloAPI:
          Type: Api
          Properties:
            Path: /hello
            Method: GET
            RestApiId: !Ref MyApi

这是我的处理函数

exports.hello = async (event) => {
    const response = {
        statusCode: 200,
        headers: {
            "Access-Control-Allow-Origin": "*", // Required for CORS support to work
            "Content-Type": "application/json",
            "Access-Control-Allow-Credentials": true, // Required for cookies, authorization headers with HTTPS
        },
        body: JSON.stringify({ message: "Hello World!" }),
    };

    callback(null, response);
};

还是报错：

 No 'Access-Control-Allow-Origin' header is present on the requested resource.

【问题讨论】：

标签： aws-lambda serverless aws-sam

【解决方案1】：

由于适用于 CORS 的 API Gateway 上的 AWS 文档非常糟糕，因此将回答这个问题以供将来参考。和这狗混战了将近三天，最终结果如下。

首先，在你的SAM模板的AWS::Serverless::Api段中，配置CORS，例如：

    Type: AWS::Serverless::Api
    Properties:
      StageName: prod
      Cors:
        AllowHeaders: "'*'"
        AllowOrigin: "'*'"
        AllowCredentials: "'*'"
        AllowMethods: "'*'"

接下来，创建一个愚蠢的虚拟 lambda 来处理任何 OPTIONS 请求，确保该 lambda 设置响应的标头。像这样的：

export const handler = async (
  event: APIGatewayProxyEvent
): Promise<APIGatewayProxyResult> => {
  return {
    headers: {
      "Access-Control-Allow-Origin" : "*", // Required for CORS support to work
      "Access-Control-Allow-Headers" : "*", // Required for CORS support to work
      "Access-Control-Allow-Credentials" : true // Required for cookies, authorization headers with HTTPS
    },
    statusCode: 200
  };
}

最后，在您的 SAM 模板中，收集所有端点并将它们指向这个愚蠢的 lambda。

  OptionHandler:
    Type: AWS::Serverless::Function
    Properties:
      Handler: <lambda above>
      Runtime: nodejs14.x
      Architectures:
        - arm64
      Timeout: 2
      Events:
        Method1APIOptions:
          Type: Api
          Properties:
            Path: /path/{param}
            Method: options
            RestApiId:
              Ref: ApiGatewayApi
        Method2APIOptions:
          Type: Api
          Properties:
            Path: /path2/{param}
            Method: options
            RestApiId:
              Ref: ApiGatewayApi
        Method3APIOptions:
          Type: Api
          Properties:
            Path: /path3/{params}
            Method: options
            RestApiId:
              Ref: ApiGatewayApi

现在每次使用 sam deploy 部署此 API 时，CORS 都不会搞砸。

【讨论】：

【解决方案2】：

试试这个：

Resources:
  MyApi:
    Type: AWS::Serverless::Api
    Properties:
      StageName: dev
      Cors:
        AllowOrigin: "'*'"
        AllowHeaders: "'*'"
      Auth:
        AddDefaultAuthorizerToCorsPreflight: False
        DefaultAuthorizer: MyLambdaTokenAuthorizer
        Authorizers:
          MyLambdaTokenAuthorizer:
            FunctionArn: !GetAtt MyAuthFunction.Arn

  HelloFunction:
    Type: AWS::Serverless::Function
    Properties:
      Handler: functions/hello/handler.hello
      CodeUri: "."
      Events:
        HelloAPI:
          Type: Api
          Properties:
            Path: /hello
            Method: get
            RestApiId: !Ref MyApi
        HelloAPIOptions:
          Type: Api
          Properties:
            Path: /hello
            Method: options
            RestApiId: !Ref MyApi

我更改了核心策略并为OPTIONS /hello 添加了一个端点。

【讨论】：