Question

我正在设置一个AWS Lambda函数以连接到我的DynamoDB。要访问它，我还要设置一个API网关。

当我测试时，lambda似乎可以正常工作。因此，我认为问题出在API网关设置中。

对于lambda，我已经配置了以下测试事件：我配置了一个如下所示的测试事件：

{
  "httpMethod": "GET"
}

此测试事件给我以下响应：

Response:
{
  "statusCode": "200",
  "body": "{\"Items\":[{\"id\":1,\"brand\":\"Test brand\",\"title\":\"Test product\"}],\"Count\":1,\"ScannedCount\":1}",
  "headers": {
    "Content-Type": "application/json"
  }
}

对于API网关，我尝试了以下测试：

我尝试在lambda管理控制台中自动创建API网关。重新创建lambda和API网关。

Lambda函数：

console.log('Loading function');

const doc = require('dynamodb-doc');

const dynamo = new doc.DynamoDB();


/**
 * Demonstrates a simple HTTP endpoint using API Gateway. You have full
 * access to the request and response payload, including headers and
 * status code.
 *
 * To scan a DynamoDB table, make a GET request with the TableName as a
 * query string parameter. To put, update, or delete an item, make a POST,
 * PUT, or DELETE request respectively, passing in the payload to the
 * DynamoDB API as a JSON body.
 */
exports.handler = (event, context, callback) => {
    //console.log('Received event:', JSON.stringify(event, null, 2));

    const done = (err, res) => callback(null, {
        statusCode: err ? '400' : '200',
        body: err ? err.message : JSON.stringify(res),
        headers: {
            'Content-Type': 'application/json',
        },
    });

    switch (event.httpMethod) {
        case 'DELETE':
            dynamo.deleteItem(JSON.parse(event.body), done);
            break;
        case 'GET':
            dynamo.scan({ "TableName": "productdb" }, done);
            //dynamo.scan({"TableName":"productdb"})
            break;
        case 'POST':
            dynamo.putItem(JSON.parse(event.body), done);
            break;
        case 'PUT':
            dynamo.updateItem(JSON.parse(event.body), done);
            break;
        default:
            done(new Error(`Unsupported method "${event.httpMethod}"`));
    }
};

测试中的API网关日志：

Execution log for request 885e5505-2212-11e9-aee0-7f024016f574
Sun Jan 27 09:04:20 UTC 2019 : Starting execution for request: 885e5505-2212-11e9-aee0-7f024016f574
Sun Jan 27 09:04:20 UTC 2019 : HTTP Method: GET, Resource Path: /
Sun Jan 27 09:04:20 UTC 2019 : Method request path: {}
Sun Jan 27 09:04:20 UTC 2019 : Method request query string: {}
Sun Jan 27 09:04:20 UTC 2019 : Method request headers: {}
Sun Jan 27 09:04:20 UTC 2019 : Method request body before transformations: 
Sun Jan 27 09:04:20 UTC 2019 : Endpoint request URI: https://lambda.eu-central-1.amazonaws.com/2015-03-31/functions/arn:aws:lambda:eu-central-1:304886708348:function:dynamoDBService/invocations
Sun Jan 27 09:04:20 UTC 2019 : Endpoint request headers: {x-amzn-lambda-integration-tag=885e5505-2212-11e9-aee0-7f024016f574, Authorization=*****************************************************************************************************************************************************************************************************************************************************************************************500617, X-Amz-Date=20190127T090420Z, x-amzn-apigateway-api-id=lqhm3agxxf, X-Amz-Source-Arn=arn:aws:execute-api:eu-central-1:304886708348:lqhm3agxxf/test-invoke-stage/GET/, Accept=application/json, User-Agent=AmazonAPIGateway_lqhm3agxxf, X-Amz-Security-Token=FQoGZXIvYXdzEOH//////////wEaDFvawdYGjH/+gSI14yK9AzQFZtlDghAr2NUHIhLGWmeJkKL8sUP3L6fu0h5PtFPN7wA7hgfWMtUNHCWyGykG0g5Zs81zKx5bUGMLCMK2zuVwD4WMgBRmkx40bZYehHdeS8czOxRTbQIqwP1lfZ0d74l4MqG4g8XpigkcLACLEn6buaq37rO4WYOo+J8ecFeSpti+u+V8OON4idxxXEHiYGJEc23OwjVvf3GTr1EUscB+Lsp/nw58oCWQArUA6LLSwcnGYXYcmnPav2Xs8mJgvqnVowxxYre0N8Gca8D9XBN2Y93/qnVTsOI5nWHSUQOnwaoXSZzgBAXKrUV1S5X+UH3zQI9p [TRUNCATED]
Sun Jan 27 09:04:20 UTC 2019 : Endpoint request body after transformations: 
Sun Jan 27 09:04:20 UTC 2019 : Sending request to https://lambda.eu-central-1.amazonaws.com/2015-03-31/functions/arn:aws:lambda:eu-central-1:304886708348:function:dynamoDBService/invocations
Sun Jan 27 09:04:20 UTC 2019 : Received response. Integration latency: 17 ms
Sun Jan 27 09:04:20 UTC 2019 : Endpoint response body before transformations: {"statusCode":"400","body":"Unsupported method \"undefined\"","headers":{"Content-Type":"application/json"}}
Sun Jan 27 09:04:20 UTC 2019 : Endpoint response headers: {Date=Sun, 27 Jan 2019 09:04:20 GMT, Content-Type=application/json, Content-Length=108, Connection=keep-alive, x-amzn-RequestId=6c00229e-caa1-4d37-aeaa-7c1cbd0ddd71, x-amzn-Remapped-Content-Length=0, X-Amz-Executed-Version=$LATEST, X-Amzn-Trace-Id=root=1-5c4d7414-e52b0fba267596b50fdbb102;sampled=0}
Sun Jan 27 09:04:20 UTC 2019 : Method response body after transformations: {"statusCode":"400","body":"Unsupported method \"undefined\"","headers":{"Content-Type":"application/json"}}
Sun Jan 27 09:04:20 UTC 2019 : Method response headers: {X-Amzn-Trace-Id=Root=1-5c4d7414-e52b0fba267596b50fdbb102;Sampled=0, Access-Control-Allow-Origin=*, Content-Type=application/json}
Sun Jan 27 09:04:20 UTC 2019 : Successfully completed execution
Sun Jan 27 09:04:20 UTC 2019 : Method completed with status: 200

我希望结果与lambda返回中的测试事件相同。

Answer 1

创建API方法时，需要选择选项“使用Lambda代理集成”，以便{{1}中的httpMethod字段以及API网关中的其他信息可以访问}}对象放在Lambda函数中。

来自docs：

您可以为任何API方法设置Lambda代理集成。但是一个将Lambda代理集成配置为涉及通用代理资源的API方法。通用代理资源可以由以下特殊的模板化路径变量表示 {proxy +}，所有ANY方法的占位符，或两者兼而有之。客户端可以将输入传递给传入的后端Lambda函数请求作为请求参数或适用的有效负载。要求参数包括标题，URL路径变量，查询字符串参数以及适用的有效负载。集成的Lambda函数在处理请求之前验证所有输入源，并如果有意义，则使用有意义的错误消息响应客户端缺少必需的输入。

您可以在API网关实例的“创建方法”屏幕上找到“使用Lambda代理集成”选项：

编辑：作为参考，您可以知道API Gateway方法未使用Lambda代理集成，因为在“集成请求”下类型为“ LAMBDA”，但是在使用Lambda代理集成时类型为“ LAMBDA_PROXY”。

Answer 2

我通过将有效负载格式更改为 V1.0（在路由的集成详细信息下）解决了 HTTP API 的问题。

Answer 3

对于无法使上述解决方案起作用的任何人，我不得不更改最初构建 Lambda 函数时使用的 http 方法的 switch 语句

来自：switch (event.httpMethod) {

至：switch (event.requestContext.http.method) {

我认为 V1.0 使用 event.httpMethod？但我无法更改 API Gateway 中的版本（消息：“API Gateway 托管资源仅供查看”）。所以我不得不更改 switch 语句以匹配 event 对象。

AWS API Gateway“不支持的方法\“ undefined \”“作为响应

3 个答案: