AppSync向Lambda发送的事件请求可以在Lambda函数中使用event参数进行访问。该事件参数是一个包含AppSync请求的JSON对象。

以下是一个JSON示例，其中包含了一个使用GraphQL进行查询的AppSync请求：

{
    "arguments": {
        "input": {
            "name": "John Doe",
            "email": "johndoe@email.com"
        }
    },
    "identity": {
        "claims": {
            "cognito:username": "johndoe"
        },
        "defaultAuthStrategy": "ALLOW"
    },
    "info": {
        "fieldName": "createUser",
        "parentTypeName": "Mutation",
        "selectionSetList": [
            "{",
            "  id",
            "  name",
            "  email",
            "  createdAt",
            "}"
        ],
        "selectionSetGraphQL": "{ id name email createdAt }",
        "variables": {
            "input": {
                "name": "John Doe",
                "email": "johndoe@email.com"
            }
        }
    },
    "request": {
        "headers": {
            "accept": "application/json",
            "content-length": "197",
            "content-type": "application/json",
            "host": "xxxxx.appsync-api.us-west-2.amazonaws.com",
            "x-amz-date": "20200101T000000Z",
            "x-amz-security-token": "xxxxxxxx",
            "x-api-key": "xxxxxxxx"
        },
        "id": "xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx",
        "method": "POST",
        "path": "/graphql",
        "protocol": "HTTP/1.1"
    },
    "source": null,
    "stash": {},
    "typeName": "Mutation"
}

在Lambda函数中，可以使用以下方法来访问该事件请求：

exports.handler = async (event, context) => {
    const request = event.request;
    const authorizationHeader = request.headers.authorization;
    const httpMethod = request.method;
    // ...
}

上述示例代码中，我们可以通过访问event.request对象来获取AppSync请求发送的