Upload file to s3 with POST

Question

I'd like to upload a file to AWS S3 via the POST interface, but I fail to do so.

I've already made it work with PUT and getSignedUrl, but unfortunately that interface doesn't allow direct file size restrictions. So I tried to use the POST interface, because there I can use 'content-length-range' condition.

Here's my request signature:

const aws = require('aws-sdk');

aws.config.update({
    signatureVersion: 'v4',
    region: 'eu-central-1',
    accessKeyId: config.aws.keyId,
    secretAccessKey: config.aws.keySecret
});

const s3 = new aws.S3();

return new Promise((resolve, reject) => {
    const params = {
        Bucket: config.aws.bucket,
        Fields: {
            key: filePath
        },
        Expires: config.aws.expire,
        Conditions: [
            ['acl', 'public-read'],
            ['content-length-range', 0, 10000000] // 10 Mb
        ]
    };
    const postUrl = s3.createPresignedPost(params, (err, data) => {
        resolve(data);
    });
});

This part seems to be OK, but I can't use the required signature to upload a file to S3.

Here are a few other attempts I made:

request.post({
    url: payload.url,
    body: payload,
    form: fs.createReadStream(__dirname + `/${filePath}`)
}, (err, response, body) => {});

Another attempt:

let formData = payload;
formData.file = fs.createReadStream(__dirname + `/${filePath}`);
request.post({ 
    url: payload.url,
    formData: formData
}, (err, response, body) => {});

With fetch:

const fetch = require('node-fetch');
const FormData = require('form-data');

const form = new FormData();
const fields = payload.fields;
for(const field in payload.fields) {
    form.append(field, payload.fields[field]);
}
form.append('file', fs.createReadStream(__dirname + `/${filePath}`));
fetch(payload.url, {
    method: 'POST',
    body: form.toString(),
    headers: form.getHeaders()
})
.then((response) => {})
.catch((err) => {});

Neither of these work, they either say 'Bad request', or 'Badly formed request'. One of them uploaded something to the server, but the file was unreadable.

How can I add a max file size limit to an S3 bucket?

Update: I think I move forward just a little. With this code, I get the error response: You must provide the Content-Length HTTP header.

const fetch = require('node-fetch');
const FormData = require('form-data');

const form = new FormData();
form.append('acl', 'public-read');
for(const field in payload.fields) {
    form.append(field, payload.fields[field]);
}
form.append('file', fs.createReadStream(__dirname + `/${filePath}`));

fetch(payload.url, {
    method: 'POST',
    body: form,
    headers: form.getHeaders()
})
.then((response) => { return response.text(); })
.then((payload) => { console.log(payload); })
.catch((err) => console.log(`Error: ${err}`));

Upload file to s3 with POST

1 Answers