AWS Lambda 在放置 s3 对象时出错

Question

我正在开发一个功能，当任何图像上传到存储桶中的图像文件夹时，通过将图像的缩略图版本保存在屏幕截图文件夹中来创建缩略图。我正在使用无服务器框架。我不断收到如下所示的错误。我已经粘贴了确切的代码，因此任何人都可以复制粘贴并实施此解决方案。 Serverless.yml、处理函数文件以及任何支持文件也包括在内。

我不知道当我提到缓冲区时为什么会收到对象类型不是缓冲区等错误。

 { InvalidParameterType: Expected params.Body to be a string, Buffer, Stream, Blob, or typed array object
at ParamValidator.fail (/var/runtime/node_modules/aws-sdk/lib/param_validator.js:50:37)
at ParamValidator.validatePayload (/var/runtime/node_modules/aws-sdk/lib/param_validator.js:255:10)
at ParamValidator.validateScalar (/var/runtime/node_modules/aws-sdk/lib/param_validator.js:133:21)
at ParamValidator.validateMember (/var/runtime/node_modules/aws-sdk/lib/param_validator.js:94:21)
at ParamValidator.validateStructure (/var/runtime/node_modules/aws-sdk/lib/param_validator.js:75:14)
at ParamValidator.validateMember (/var/runtime/node_modules/aws-sdk/lib/param_validator.js:88:21)
at ParamValidator.validate (/var/runtime/node_modules/aws-sdk/lib/param_validator.js:34:10)
at Request.VALIDATE_PARAMETERS (/var/runtime/node_modules/aws-sdk/lib/event_listeners.js:125:42)
at Request.callListeners (/var/runtime/node_modules/aws-sdk/lib/sequential_executor.js:105:20)
at callNextListener (/var/runtime/node_modules/aws-sdk/lib/sequential_executor.js:95:12)
message: 'Expected params.Body to be a string, Buffer, Stream, Blob, or typed array object',
code: 'InvalidParameterType',
time: 2019-03-12T16:37:26.910Z }

代码：

Handler.js

'use strict';

const resizer = require('./resizer');

module.exports.resizer = (event, context, callback) => {
	console.log(event.Records[0].s3);

	const bucket = event.Records[0].s3.bucket.name;
	const key = event.Records[0].s3.object.key;

	console.log(`A file named ${key} was put in a bucket ${bucket}`);

	resizer(bucket, key)
		.then(() => {
			console.log(`The thumbnail was created`);
			callback(null, {
				message: 'The thumbnail was created'
			});
		})
		.catch(error => {
			console.log(error);
			callback(error);
		});
};

module.exports.thumbnails = (event, context, callback) => {
	const bucket = event.Records[0].s3.bucket.name;
	const key = event.Records[0].s3.object.key;

	console.log(bucket);
	console.log(key);

	console.log(`A new file ${key} was created in the bucket ${bucket}`);
	callback(null, {
		message: `A new file ${key} was created in the bucket ${bucket}`
	});
};

Resizer.js

'use strict';

const AWS = require('aws-sdk');
const S3 = new AWS.S3();
const Jimp = require('jimp'); //https://github.com/oliver-moran/jimp

module.exports = (bucket, key) => {
	const newKey = replacePrefix(key);
	const height = 512;

	return getS3Object(bucket, key).then(data => resizer(data.Body, height)).then(buffer => putS3Object(bucket, newKey, buffer));
};

function getS3Object(bucket, key) {
	return S3.getObject({
		Bucket: bucket,
		Key: key
	}).promise();
}

function putS3Object(bucket, key, body) {
	return S3.putObject({
		Body: body,
		Bucket: bucket,
		ContentType: 'image/jpg',
		Key: key
	}).promise();
}

function replacePrefix(key) {
	const uploadPrefix = 'uploads/';
	const thumbnailsPrefix = 'thumbnails/';
	return key.replace(uploadPrefix, thumbnailsPrefix);
}

function resizer(data, height) {
	return Jimp.read(data)
		.then(image => {
			return image
				.resize(Jimp.AUTO, height)
				.quality(100) // set JPEG quality
				.getBuffer(Jimp.MIME_JPEG, (err, buffer) => {
					return buffer;
				});
		})
		.catch(err => err);
}

无服务器.yml

service: serverless-resizer-project # NOTE: update this with your service name


provider:
  name: aws
  runtime: nodejs6.10
  profile: student1

  iamRoleStatements:
    - Effect: "Allow"
      Action:
        - "s3:ListBucket"
        - "s3:GetObject"
        - "s3:PutObject"
      Resource: "arn:aws:s3:::serverless-resizer-project-images/*"

functions:
  resizer:
    handler: handler.resizer
    events:
      - s3:
          bucket: serverless-resizer-project-images
          event: s3:ObjectCreated:*
          rules:
            - prefix: uploads/
            - suffix: .jpg
	thumbnails:
    handler: handler.thumbnails
    events:
      - s3:
          bucket: serverless-resizer-project-images
          event: s3:ObjectCreated:*
          rules:
            - prefix: thumbnails/
            - suffix: .jpg					

Answer 1

resizer 函数的返回值不是您所期望的。您正在使用带有回调的getBuffer 函数，这意味着图像的缓冲区不是由promise 解析的，而是在回调中使用，这不是您的意图。您应该改用getBufferAsync，它返回一个解析为图像缓冲区的promise。您的 resizer 函数应该如下所示：

function resizer(data, height) {
    return Jimp.read(data)
        .then(image => image
                .resize(Jimp.AUTO, height)
                .quality(100) // set JPEG quality
                .getBufferAsync(Jimp.MIME_JPEG)
        )
        .catch(err => err);
}