I'm quite new to node.js and would like to do the following:
user can upload one file
upload should be saved to amazon s3
file information should be saved to a database
script shouldn't be limited to specific file size
As I've never used S3 or done uploads before I might have some
wrong ideas - please correct me, if I'm wrong.
So in my opinion the original file name should be saved into the db and returned for download but the file on S3 should be renamed to my database entry id to prevent overwriting files. Next, should the files be streamed or something? I've never done this but it just seems not to be smart to cache files on the server to then push them to S3, does it?
Thanks for your help!
At first I recommend to look at knox module for NodeJS. It is from quite reliable source. https://github.com/LearnBoost/knox
I write a code below for Express module, but if you do not use it or use another framework, you should still understand basics. Take a look at CAPS_CAPTIONS in the code, you want to change them according to your needs / configuration. Please also read comments to understand pieces of code.
app.post('/YOUR_REQUEST_PATH', function(req, res, next){
var fs = require("fs")
var knox = require("knox")
var s3 = knox.createClient({
key: 'YOUR PUBLIC KEY HERE' // take it from AWS S3 configuration
, secret: 'YOUR SECRET KEY HERE' // take it from AWS S3 configuration
, bucket: 'YOUR BUCKET' // create a bucket on AWS S3 and put the name here. Configure it to your needs beforehand. Allow to upload (in AWS management console) and possibly view/download. This can be made via bucket policies.
})
fs.readFile(req.files.NAME_OF_FILE_FIELD.path, function(err, buf){ // read file submitted from the form on the fly
var s3req = s3.put("/ABSOLUTE/FOLDER/ON/BUCKET/FILE_NAME.EXTENSION", { // configure putting a file. Write an algorithm to name your file
'Content-Length': buf.length
, 'Content-Type': 'FILE_MIME_TYPE'
})
s3req.on('response', function(s3res){ // write code for response
if (200 == s3res.statusCode) {
// play with database here, use s3req and s3res variables here
} else {
// handle errors here
}
})
s3req.end(buf) // execute uploading
})
})
Related
I am currently trying to download the file from the s3 bucket using a button from the front-end. How is it possible to do this? I don't have any idea on how to start this thing. I have tried researching and researching, but no luck -- all I have searched are about UPLOADING files to the s3 bucket but not DOWNLOADING files. Thanks in advance.
NOTE: I am applying it to ReactJS (Frontend) and NodeJS (Backend) and also, the file is uploaded using Webmerge
UPDATE: I am trying to generate a download link with this (Tried node even if I'm not a backend dev) (lol)
see images below
what I have tried so far
onClick function
If the file you are trying to download is not public then you have to create a signed url to get that file.
The solution is here Javascript to download a file from amazon s3 bucket?
for getting non public files, which revolves around creating a lambda function that will generate a signed url for you then use that url to download the file on button click
BUT if the file you are trying to download you is public then you don't need a signed url, you just need to know the path to the file, the urls are structured like: https://s3.amazonaws.com/ [file path]/[filename]
They is also aws amplify its created and maintain by AWS team.
Just follow Get started and downloading the file from your react app is simply as:
Storage.get('hello.png', {expires: 60})
.then(result => console.log(result))
.catch(err => console.log(err));
Here is my solution:
let downloadImage = url => {
let urlArray = url.split("/")
let bucket = urlArray[3]
let key = `${urlArray[4]}/${urlArray[5]}`
let s3 = new AWS.S3({ params: { Bucket: bucket }})
let params = {Bucket: bucket, Key: key}
s3.getObject(params, (err, data) => {
let blob=new Blob([data.Body], {type: data.ContentType});
let link=document.createElement('a');
link.href=window.URL.createObjectURL(blob);
link.download=url;
link.click();
})
}
The url in the argument refers to the url of the S3 file.
Just put this in the onClick method of your button. You will also need the AWS SDK
I have been using GCS to storage my images and also use the NodeJS package to upload these images to my bucket. I have noticed that if I frequently change an image, it either does one of the following:
It changes
It serves an old image
It doesn't change
This seems to happen pretty randomly despite setting all of the options properly and even cross-referencing that with GCS.
I upload my images like this:
const options = {
destination,
public: true,
resumable: false,
metadata: {
cacheControl: 'no-cache, max-age=0',
},
};
const file = await this.bucket.upload(tempImageLocation, options);
const { bucket, name, generation } = file[0].metadata;
const imageUrl = `https://storage.googleapis.com/${bucket}/${name}`;
I have debated whether to use the base URL you see there or use this one: https://storage.cloud.google.com.
I can't seem to figure out what I am doing wrong and how to always serve a fresh image. I have also tried ?ignoreCache=1 and other query parameters.
As per the official API documentation - accessible here - shows, you should not need the await. This might be affecting your upload sometime. If you want to use the await, you need to have your function to be async in the declaration, as showed in the second example from the documentation. Your code should look like this.
const bucketName = 'Name of a bucket, e.g. my-bucket';
const filename = 'Local file to upload, e.g. ./local/path/to/file.txt';
const {Storage} = require('#google-cloud/storage');
const storage = new Storage();
async function uploadFile() {
// Uploads a local file to the bucket
await storage.bucket(bucketName).upload(filename, {
// Support for HTTP requests made with `Accept-Encoding: gzip`
gzip: true,
// By setting the option `destination`, you can change the name of the
// object you are uploading to a bucket.
metadata: {
// Enable long-lived HTTP caching headers
// Use only if the contents of the file will never change
// (If the contents will change, use cacheControl: 'no-cache')
cacheControl: 'public, max-age=31536000',
},
});
console.log(`${filename} uploaded to ${bucketName}.`);
}
uploadFile().catch(console.error);
While this is untested, it should help you avoiding the issue with not uploading always the images.
Besides that, as explained in the official documentation of Editing Metada, you can change the way that metadata - which includes the cache control - is used and managed by your project. This way, you can change your cache configuration as well.
I also, would like to include the below link for a complete tutorial on how to send images to Cloud Storage with Node.js, in case you want to check a different approach.
Image Upload With Google Cloud Storage and Node.js
Let me know if the information helped you!
u can try change ?ignoreCache=1 to ?ignoreCache=0.
So I want to pipe a file straight to the client; how I am currently doing it is create a file to disk, then sending that file straight to the client.
router.get("/download/:name", async (req, res) => {
const s3 = new aws.S3();
const dir = "uploads/" + req.params.name + ".apkg"
let file = fs.createWriteStream(dir);
await s3.getObject({
Bucket: <bucket-name>,
Key: req.params.name + ".apkg"
}).createReadStream().pipe(file);
await res.download(dir);
});
I just looked up that res.download() only serves locally. Is there a way you can do it directly from AWS S3 to Client download? i.e. pipe files straight to user. Thanks in advance
As described in this SO thread:
You can simply pipe the read stream into the response instead of the piping it to the file, just make sure to supply the correct Content-Type and to set it as an attachment, so the browser will know how to handle the response properly.
res.attachment(req.params.name);
await s3.getObject({
Bucket: <bucket-name>,
Key: req.params.name + ".apkg"
}).createReadStream().pipe(res);
On more pattern for this is to create a signed url directly to the S3 object and then let the client download straight from S3, instead of streaming it from your node webserver. This will reduce the workload from your web server.
You will need to use the getSignedUrl method from the AWS S3 SDK for JS.
Then, Once you have the URL, just return it to your client to download the file by themselves.
You should take into account that once you give the client a signed URL that has download permissions for, say, 5 minutes, they will only be able to download that file during those next 5 minutes. And you should also take into account that they will be able to pass that URL to anyone else for download during those 5 minutes, so it is dependant on how secure you need this to be.
S3 can be used to content so I would do the following.
Add CORS headers on your node response. This will enable browser to download from another origin i.e. S3.
Enable S3 web server on your bucket.
Script to download redirect from S3 - this you could achieve in JS.
Use signed URL as suggested in the other post if you need to protect S3 content.
I am trying to use aws s3 image in lambda node js but it throws an error 'no such file or directory'. But I have made that image as public and all permissions are granted.
fs = require('fs');
exports.handler = function( event, context ) {
var img = fs.readFileSync('https://s3-us-west-2.amazonaws.com/php-7/pic_6.png');
res.writeHead(200, {'Content-Type': 'image/png' });
res.end(img, 'binary');
};
fs is node js file system core module. It is for writing and reading files on local machine. That is why it gives you that error.
There are multiple things wrong with your code.
fs is a core module used for file operations and can't be used to access S3.
You seem to be using express.js code in your example. In lambda, there is no built-in res defined(unless you define it yourself) that you can use to send response.
You need to use the methods on context or the new callback mechanism. The context methods are used on the older lambda node version(0.10.42). You should be using the newer node version(4.3.2 or 6.10) which return response using the callback parameter.
It seems like you are also using the API gateway, so assuming that, I'll give a few suggestions. If the client needs access to the S3 object, these are some of your options:
Read the image from S3 using the AWS sdk and return the image using the appropriate binary media type. AWS added support for binary data for API gateway recently. See this link OR
Send the public S3 URL to client in your json response. Consider whether the S3 objects need to be public. OR
Use the S3 sdk to generate pre-signed URLs that are valid for a configured duration back to the client.
I like the pre-signed URL approach. I think you should check that out. You might also want to check the AWS lambda documentation
To get a file from S3, you need to use the path that S3 give you. The base path is https://s3.amazonaws.com/{your-bucket-name}/{your-file-name}.
On your code, you must replace the next line:
var img = fs.readFileSync('https://s3.amazonaws.com/{your-bucket-name}/pic_6.png');
If don't have a bucket, you should to create one to give permissions.
I'm working on a project using Google Cloud Storage to allow users to upload media files into a predefined bucket using Node.js. I've been testing with small .jpg files. I also used gsutil to set bucket permissions to public.
At first, all files generated links that downloaded the file. Upon investigation of the docs, I learned that I could explicitly set the Content-Type of each file after upload using the gsutil CLI. When I used this procedure to set the filetype to 'image/jpeg', the link behavior changed to display the image in the browser. But this only worked if the link had not been previously clicked prior to updating the metadata with gsutil. I thought that this might be due to browser caching, but the behavior was duplicated in an incognito browser.
Using gsutil to set the mime type would be impractical at any rate, so I modified the code in my node server POST function to set the metadata at upload time using an npm module called mime. Here is the code:
app.post('/api/assets', multer.single('qqfile'), function (req, res, next) {
console.log(req.file);
if (!req.file) {
return ('400 - No file uploaded.');
}
// Create a new blob in the bucket and upload the file data.
var blob = bucket.file(req.file.originalname);
var blobStream = blob.createWriteStream();
var metadata = {
contentType: mime.lookup(req.file.originalname)
};
blobStream.on('error', function (err) {
return next(err);
});
blobStream.on('finish', function () {
blob.setMetadata(metadata, function(err, response){
console.log(response);
// The public URL can be used to directly access the file via HTTP.
var publicUrl = format(
'https://storage.googleapis.com/%s/%s',
bucket.name, blob.name);
res.status(200).send(
{
'success': true,
'publicUrl': publicUrl,
'mediaLink': response.mediaLink
});
});
});
blobStream.end(req.file.buffer);
});
This seems to work, from the standpoint that it does actually set the Content-Type on upload, and that is correctly reflected in the response object as well as the Cloud Storage console. The issue is that some of the links returned as publicUrl cause a file download, and others cause a browser load of the image. Ideally I would like to have both options available, but I am unable to see any difference in the stored files or their metadata.
What am I missing here?
Google Cloud Storage makes no assumptions about the content-type of uploaded objects. If you don't specify, GCS will simply assign a type of "application/octet-stream".
The command-line tool gsutil, however, is smarter, and will attach the right Content-Type to files being uploaded in most cases, JPEGs included.
Now, there are two reasons why your browser is likely to download images rather than display them. First, if the Content-Type is set to "application/octet-stream", most browsers will download the results as a file rather than display them. This was likely happening in your case.
The second reason is if the server responds with a 'Content-Disposition: attachment' header. This doesn't generally happen when you fetch GCS objects from the host "storage.googleapis.com" as you are doing above, but it can if you, for instance, explicitly specified a contentDisposition for the object that you've uploaded.
For this reason I suspect that some of your objects don't have an "image/jpeg" content type. You could go through and set them all with gsutil like so: gsutil -m setmeta 'Content-Type:image/jpeg' gs://myBucketName/**