其他解决方案非常适合文件不多（小于~60）。如果他们处理更多文件，他们就会毫无错误地退出。这是因为他们打开了太多的流。
这个解决方案的灵感来自https://gist.github.com/amiantos/16bacc9ed742c91151fcf1a41012445e
这是一个有效的解决方案，即使处理许多文件 (+300) 也能很好地工作，并将预签名的 URL 返回到包含文件的 zip。
主 Lambda：
const AWS = require('aws-sdk');
const S3 = new AWS.S3({
apiVersion: '2006-03-01',
signatureVersion: 'v4',
httpOptions: {
timeout: 300000 // 5min Should Match Lambda function timeout
}
});
const archiver = require('archiver');
import stream from 'stream';
const UPLOAD_BUCKET_NAME = "my-s3-bucket";
const URL_EXPIRE_TIME = 5*60;
export async function getZipSignedUrl(event) {
const prefix = `uploads/id123123/}`; //replace this with your S3 prefix
let files = ["12314123.png", "56787567.png"] //replace this with your files
if (files.length == 0) {
console.log("No files to zip");
return result(404, "No pictures to download");
}
console.log("Files to zip: ", files);
try {
files = files.map(file => {
return {
fileName: file,
key: prefix + '/' + file,
type: "file"
};
});
const destinationKey = prefix + '/' + 'uploads.zip'
console.log("files: ", files);
console.log("destinationKey: ", destinationKey);
await streamToZipInS3(files, destinationKey);
const presignedUrl = await getSignedUrl(UPLOAD_BUCKET_NAME, destinationKey, URL_EXPIRE_TIME, "uploads.zip");
console.log("presignedUrl: ", presignedUrl);
if (!presignedUrl) {
return result(500, null);
}
return result(200, presignedUrl);
}
catch(error) {
console.error(`Error: ${error}`);
return result(500, null);
}
}
辅助函数：
export function result(code, message) {
return {
statusCode: code,
body: JSON.stringify(
{
message: message
}
)
}
}
export async function streamToZipInS3(files, destinationKey) {
await new Promise(async (resolve, reject) => {
var zipStream = streamTo(UPLOAD_BUCKET_NAME, destinationKey, resolve);
zipStream.on("error", reject);
var archive = archiver("zip");
archive.on("error", err => {
throw new Error(err);
});
archive.pipe(zipStream);
for (const file of files) {
if (file["type"] == "file") {
archive.append(getStream(UPLOAD_BUCKET_NAME, file["key"]), {
name: file["fileName"]
});
}
}
archive.finalize();
})
.catch(err => {
console.log(err);
throw new Error(err);
});
}
function streamTo(bucket, key, resolve) {
var passthrough = new stream.PassThrough();
S3.upload(
{
Bucket: bucket,
Key: key,
Body: passthrough,
ContentType: "application/zip",
ServerSideEncryption: "AES256"
},
(err, data) => {
if (err) {
console.error('Error while uploading zip')
throw new Error(err);
reject(err)
return
}
console.log('Zip uploaded')
resolve()
}
).on("httpUploadProgress", progress => {
console.log(progress)
});
return passthrough;
}
function getStream(bucket, key) {
let streamCreated = false;
const passThroughStream = new stream.PassThrough();
passThroughStream.on("newListener", event => {
if (!streamCreated && event == "data") {
const s3Stream = S3
.getObject({ Bucket: bucket, Key: key })
.createReadStream();
s3Stream
.on("error", err => passThroughStream.emit("error", err))
.pipe(passThroughStream);
streamCreated = true;
}
});
return passThroughStream;
}
export async function getSignedUrl(bucket: string, key: string, expires: number, downloadFilename?: string): Promise<string> {
const exists = await objectExists(bucket, key);
if (!exists) {
console.info(`Object ${bucket}/${key} does not exists`);
return null
}
let params = {
Bucket: bucket,
Key: key,
Expires: expires,
};
if (downloadFilename) {
params['ResponseContentDisposition'] = `inline; filename="${encodeURIComponent(downloadFilename)}"`;
}
try {
const url = s3.getSignedUrl('getObject', params);
return url;
} catch (err) {
console.error(`Unable to get URL for ${bucket}/${key}`, err);
return null;
}
};