我的目标：
显示一个对话框，提示用户保存从 aws 下载的文件。
我的问题：
我目前正在使用 awssum-amazon-s3 创建下载流。但是，我只能设法将文件保存到我的服务器或将其流式传输到命令行...正如您从我的代码中看到的，我的最后一次尝试是尝试手动设置失败的内容处置标头。我无法使用 res.download() 因为标头已设置？
我怎样才能实现我的目标？
我的节点代码：
app.post('/dls/:dlKey', function(req, res, next){
// download the file via aws s3 here
var dlKey = req.param('dlKey');
Dl.findOne({key:dlKey}, function(err, dl){
if (err) return next(err);
var files = dl.dlFile;
var options = {
BucketName : 'xxxx',
ObjectName : files,
};
s3.GetObject(options, { stream : true }, function(err, data) {
// stream this file to stdout
fmt.sep();
data.Headers['Content-Disposition'] = 'attachment';
console.log(data.Headers);
data.Stream.pipe(fs.createWriteStream('test.pdf'));
data.Stream.on('end', function() {
console.log('File Downloaded!');
});
});
});
res.end('Successful Download Post!');
});
我的角度代码：
$scope.dlComplete = function (dl) {
$scope.procDownload = true;
$http({
method: 'POST',
url: '/dls/' + dl.dlKey
}).success(function(data/*, status, headers, config*/) {
console.log(data);
$location.path('/#!/success');
}).error(function(/*data, status, headers, config*/) {
console.log('File download failed!');
});
};
此代码的目的是让用户使用生成的密钥下载一次文件。
这是在最新版本的 aws-sdk 上使用流式传输的完整代码
var express = require('express');
var app = express();
var fs = require('fs');
app.get('/', function(req, res, next){
res.send('You did not say the magic word');
});
app.get('/s3Proxy', function(req, res, next){
// download the file via aws s3 here
var fileKey = req.query['fileKey'];
console.log('Trying to download file', fileKey);
var AWS = require('aws-sdk');
AWS.config.update(
{
accessKeyId: "....",
secretAccessKey: "...",
region: 'ap-southeast-1'
}
);
var s3 = new AWS.S3();
var options = {
Bucket : '/bucket-url',
Key : fileKey,
};
res.attachment(fileKey);
var fileStream = s3.getObject(options).createReadStream();
fileStream.pipe(res);
});
var server = app.listen(3000, function () {
var host = server.address().address;
var port = server.address().port;
console.log('S3 Proxy app listening at http://%s:%s', host, port);
});
只需从 S3 创建一个 ReadStream，并为您要下载的位置创建 WriteStream。
const AWS = require('aws-sdk');
const path = require('path');
const fs = require('fs');
AWS.config.loadFromPath(path.resolve(__dirname, 'config.json'));
AWS.config.update({
accessKeyId: AWS.config.credentials.accessKeyId,
secretAccessKey: AWS.config.credentials.secretAccessKey,
region: AWS.config.region
});
const s3 = new AWS.S3();
const params = {
Bucket: '<your-bucket>',
Key: '<path-to-your-file>'
};
const readStream = s3.getObject(params).createReadStream();
const writeStream = fs.createWriteStream(path.join(__dirname, 's3data.txt'));
readStream.pipe(writeStream);
此代码适用于我最新的库：
var s3 = new AWS.S3();
var s3Params = {
Bucket: 'your bucket',
Key: 'path/to/the/file.ext'
};
s3.getObject(s3Params, function(err, res) {
if (err === null) {
res.attachment('file.ext'); // or whatever your logic needs
res.send(data.Body);
} else {
res.status(500).send(err);
}
});
使用AWS SDK v3
npm install @aws-sdk/client-s3
下载代码
import { GetObjectCommand } from "@aws-sdk/client-s3";
/**
* download a file from AWS and send to your rest client
*/
app.get('/download', function(req, res, next){
var fileKey = req.query['fileKey'];
var bucketParams = {
Bucket: 'my-bucket-name',
Key: fileKey,
};
res.attachment(fileKey);
var fileStream = await s3Client.send(new GetObjectCommand(bucketParams));
// for TS you can add: if (fileStream.Body instanceof Readable)
fileStream.Body.pipe(res)
});
您已经知道解决问题最重要的是什么：您可以将来自 S3 的文件流传输到任何可写流，无论是文件流……还是将发送到客户端的响应流！
s3.GetObject(options, { stream : true }, function(err, data) {
res.attachment('test.pdf');
data.Stream.pipe(res);
});
res.attachment为此，我使用
React frontendnode js backend==== Node js 后端代码 (AWS S3) ======
//在
GET public download = (req: Request, res: Response) => {
const keyName = req.query.keyName as string;
if (!keyName) {
throw new Error('key is undefined');
}
const downloadParams: AWS.S3.GetObjectRequest = {
Bucket: this.BUCKET_NAME,
Key: keyName
};
this.s3.getObject(downloadParams, (error, data) => {
if (error) {
return error;
}
res.send(data.Body);
res.end();
});
};
======React js前端代码========
//此函数处理下载按钮
onClick const downloadHandler = async (keyName: string) => {
const response = await axiosInstance.get( //here use axios interceptors
`papers/paper/download?keyName=${keyName}`,{
responseType:'blob', //very very important dont miss (if not downloaded file unsupported to view)
}
);
const url = window.URL.createObjectURL(new Blob([response.data]));
const link = document.createElement("a");
link.href = url;
link.setAttribute("download", "file.pdf"); //change "file.pdf" according to saved name you want, give extension according to filetype
document.body.appendChild(link);
link.click();
link.remove();
};
------ 或者（如果您使用普通的 axios 而不是 axios 拦截器）-----
axios({
url: 'http://localhost:5000/static/example.pdf',
method: 'GET',
responseType: 'blob', // very very important
}).then((response) => {
const url = window.URL.createObjectURL(new Blob([response.data]));
const link = document.createElement('a');
link.href = url;
link.setAttribute('download', 'file.pdf');
document.body.appendChild(link);
link.click();
});
使用express，基于Jushua的答案和https://docs.aws.amazon.com/AmazonS3/latest/userguide/example_s3_GetObject_section.html
public downloadFeedFile = (req: IFeedUrlRequest, res: Response) => {
const downloadParams: GetObjectCommandInput = parseS3Url(req.s3FileUrl.replace(/\s/g, ''));
logger.info("requesting S3 file " + JSON.stringify(downloadParams));
const run = async () => {
try {
const fileStream = await this.s3Client.send(new GetObjectCommand(downloadParams));
if (fileStream.Body instanceof Readable){
fileStream.Body.once('error', err => {
console.error("Error downloading s3 file")
console.error(err);
});
fileStream.Body.pipe(res);
}
} catch (err) {
logger.error("Error", err);
}
};
run();
};
使用 @aws-sdk/client-s3 的
GetObjectCommand// The following example retrieves an object for an S3 bucket.
const input = {
"Bucket": "examplebucket",
"Key": "HappyFace.jpg"
};
const command = new GetObjectCommand(input);
const response = await client.send(command);
/* response ==
{
"AcceptRanges": "bytes",
"ContentLength": "3191",
"ContentType": "image/jpeg",
"ETag": "\"6805f2cfc46c0f04559748bb039d69ae\"",
"LastModified": "Thu, 15 Dec 2016 01:19:41 GMT",
"Metadata": {},
"TagCount": 2,
"VersionId": "null"
}
*/
// example id: to-retrieve-an-object-1481827837012
要将正文流式传输到文件，在 Typescript 中：
import { Readable } from 'stream';
if (!res.Body) {
throw new Error("No body");
}
const writeStream = fs.createWriteStream(localPath);
const readStream = res.Body as Readable;
readStream.pipe(writeStream);
MIGHT HELP ANYONE
app.post("/api/posts",upload.single("demo"),async(req,res)=>{
console.log('req.body',req.body);
console.log('req.file',req.file);
console.log('req.file.asliData',req.file.buffer);
console.log('req.content-type',req.file.mimetype);
// req.file.buffer sis the actual image and we need to send it to s3
if (!req.file) {
return res.status(400).send('No file uploaded');
}
//resize image only make sure image only
// const buffer = sharp(req.file.buffer).resize({height:1920,width:1080,fit:"contain"}).toBuffer()
const params = {
Bucket:"usman.test.bucket",
Key:req.file.originalname, //file name what it should be keep it unique
Body:req.file.buffer, // what we are passing should be buffer
ContentType:req.file.mimetype //type of file gfood practice
}
try {
//Upload to bucket
const command = new PutObjectCommand(params)
const result = await s3.send(command)
res.status(200).send(`File uploaded to S3 ${result.ETag}`)
} catch (error) {
console.error('Error uploading file to S3:', error);
res.status(500).send('File upload to S3 failed');
}
})
app.get("/api/posts/:fileName", async (req, res) => {
const fileName = req.params.fileName;
const bucketName = "usman.test.bucket";
try {
const params = {
Bucket: bucketName,
Key: fileName
};
const command = new GetObjectCommand(params);
const {Body,ContentType} = await s3.send(command);
if (Body) {
const contentType = ContentType;
res.set("Content-Type", contentType);
// In a regular HTTP response, the Content-Disposition response header is a header indicating if the content is expected to be displayed inline in the browser, that is, as a Web page or as part of a Web page, or as an attachment, that is downloaded and saved locally.
// When the value is set to attachment, it tells the browser to treat the response as a downloadable file attachment.
res.set("Content-Disposition", `attachment; filename="${fileName}"`);
// Pipe the S3 response stream directly to the HTTP response
// Body from the GetObjectCommand is a readable stream thats we use pipe (pipe read from codeevolutyiuon)
Body.pipe(res);
console.log(res);
} else {
res.status(404).send("File not found");
}
} catch (error) {
console.error("Error retrieving file from S3:", error);
res.status(500).send("Error retrieving file from S3");
}
});