Stream uploaded file to Azure blob storage with Node

0 votes

Using Express with Node, I can upload a file successfully and pass it to Azure storage in the following block of code.

app.get('/upload', function (req, res) {
    res.send(
    '<form action="/upload" method="post" enctype="multipart/form-data">' +
    '<input type="file" name="snapshot" />' +
    '<input type="submit" value="Upload" />' +
    '</form>'
    );
});

app.post('/upload', function (req, res) {
    var path = req.files.snapshot.path;
    var bs= azure.createBlobService();
    bs.createBlockBlobFromFile('c', 'test.png', path, function (error) { });
    res.send("OK");
});

This works just fine, but Express creates a temporary file and stores the image first, then I upload it to Azure from the file. This seems like an inefficient and unnecessary step in the process and I end up having to manage cleanup of the temp file directory.

I should be able to stream the file directly to Azure storage using the blobService.createBlockBlobFromStream method in the Azure SDK, but I am not familiar enough with Node or Express to understand how to access the stream data.

app.post('/upload', function (req, res) {

    var stream = /// WHAT GOES HERE ?? ///

    var bs= azure.createBlobService();
    bs.createBlockBlobFromStream('c', 'test.png', stream, function (error) { });
    res.send("OK");
});

I have found the following blog which indicates that there may be a way to do so, and certainly Express is grabbing the stream data and parsing and saving it to the file system as well. vjacobs code is actually downloading a file from another site and passing that stream to Azure, so I'm not sure if it can be adapted to work in my situation.

How can I access and pass the uploaded files stream directly to Azure using Node?

Sep 24, 2018 in Azure by null_void
• 3,220 points
7,736 views
Were you able to achieve to send stream directly to azure?

If yes then could you please share the mechanism.

1 answer to this question.

0 votes

Using Multiparty(npm install multiparty), a fork of Formidable, we can access the multipart data if we disable the bodyparser() middleware from Express (see their notes on doing this for more information). Unlike Formidable, Multiparty will not stream the file to disk unless you tell it to.

app.post('/upload', function (req, res) {
    var blobService = azure.createBlobService();
    var form = new multiparty.Form();
    form.on('part', function(part) {
        if (part.filename) {

            var size = part.byteCount - part.byteOffset;
            var name = part.filename;

            blobService.createBlockBlobFromStream('c', name, part, size, function(error) {
                if (error) {
                    res.send({ Grrr: error });
                }
            });
        } else {
            form.handlePart(part);
        }
    });
    form.parse(req);
    res.send('OK');
});

Hope this helps!!

If you need to know more about Azure, then you should join Microsoft Azure certification course today.

Thank you!!

answered Sep 24, 2018 by club_seesharp
• 3,450 points

Related Questions In Azure

0 votes
1 answer

Want to upload a blob file with huge size to azure in as little time as possible.

Microsoft Azure Storage Explorer is one of the ...READ MORE

answered Mar 27, 2019 in Azure by Prerna
• 1,960 points
1,367 views
0 votes
1 answer

Why would you choose Blob Storage over File Storage which also has ability to store file(s) and folder(s)

Azure Files: Azure File storage provides shared ...READ MORE

answered Apr 13, 2018 in Azure by null_void
• 3,220 points

edited Apr 13, 2018 by null_void 1,668 views
0 votes
2 answers

Reading PDF file from Azure blob storage

For pdf reading and manipulating Itextsharp libraby is fine. For ...READ MORE

answered Aug 17, 2018 in Azure by Priyaj
• 58,020 points
7,812 views
0 votes
1 answer

Can we track progress of async file upload to azure storage?

Actually it's not possible because uploading file is ...READ MORE

answered Jun 14, 2018 in Azure by club_seesharp
• 3,450 points
5,837 views
0 votes
1 answer

Azure Blob: How to open a file in browser without downloading it?

First, because I was using a byte[] the controller ...READ MORE

answered Jun 20, 2018 in Azure by club_seesharp
• 3,450 points
24,723 views
0 votes
1 answer

How can I use “Azure File Storage” with Web App Service?

If you're looking for mapping a drive ...READ MORE

answered Aug 11, 2018 in Azure by null_void
• 3,220 points
4,281 views
0 votes
1 answer

How to Unzip file uploaded to Azure Websites?

One way is to upload the command ...READ MORE

answered Aug 14, 2018 in Azure by null_void
• 3,220 points
2,713 views
0 votes
1 answer

How to get blob-URL after file upload in azure?

Assuming you're uploading the blobs into blob ...READ MORE

answered Sep 27, 2018 in Azure by null_void
• 3,220 points
15,954 views
0 votes
1 answer

How to upload a file on to Azure Blob storage without writing a code?

You can find the below tools useful ...READ MORE

answered Apr 13, 2018 in Azure by club_seesharp
• 3,450 points
1,603 views
0 votes
1 answer

How can i upload to Azure Blob storage with Shared Access key?

For GetBlobReferenceFromServer to work, the blob must be present ...READ MORE

answered Jun 12, 2018 in Azure by club_seesharp
• 3,450 points
3,601 views
webinar REGISTER FOR FREE WEBINAR X
REGISTER NOW
webinar_success Thank you for registering Join Edureka Meetup community for 100+ Free Webinars each month JOIN MEETUP GROUP