cors issue with uploading to signed url

I have tried many configurations to get file upload with signed url. preflight request completes ok but actual upload fails with No ‘Access-Control-Allow-Origin’ header is present on the requested resource.

This makes me thin that the cors config is ok but there is an issue with the way the url is being signed. I see a lot of people having issues with this on stack overflow but no resolutions, which makes me think that this is really a documentation issue. Below is the most lenient configuration I have tried:

cors config:

[{"maxAgeSeconds": 3600, "method": ["GET", "HEAD", "POST", "PUT"], "origin": ["*"], "responseHeader": ["Content-Type", "Access-Control-Allow-Origin"]}]

serverside code:

   app.post('/api/v1/upload/gcs-sign', function(req, res) {
     const fileName = req.body.fileName;
     const fileType = req.body.fileType;
     const file = bucket.file(fileName);

     // signed URL expires in 1 hour
     const expirationDate = new Date(
        new Date().setHours(new Date().getHours() + 1),
    );
     const config = {
        action: 'resumable',
        expires: expirationDate,
        contentType: req.body.fileType,
     };
     file.getSignedUrl(config, (err, signedRequest) => {
        if (err) {
          return res.end();
        }
       res.json({ signedRequest });
      res.end();
    })

client side code:

     uploadToGCS = (signedRequest, file) => {
      let xhr = new XMLHttpRequest();
      xhr.open('POST', signedRequest);
      xhr.onload = () => {
        this.onUploadFinish(xhr);
      };
      xhr.onerror = this.onUploadError;
     xhr.upload.onprogress = this.onUploadProgress;
     xhr.setRequestHeader('Content-Type', file.type);
     xhr.send(file);
   };

Environment details

• OS: OSX 10.13.3
• Node.js version: 10.7.0
• npm version: 6.2.0
• @google-cloud/storage version: 1.7.0

Steps to reproduce

1. create bucket witth cors config above
2. run server code above ( Ive left out some basic boiler plate )
3. attempt to upload file with client side code above

Thanks!

[leonsomed]

I was using fetch with FormData to send the file, for whatever reason that did not work. I ended up doing a couple of things:

• Adding CORS configuration to the bucket as described here https://cloud.google.com/storage/docs/configuring-cors
• Switching from fetch to XMLHttpRequest to send the file
• Using PUT instead of POST
• Using Content-Type: application/octet-stream in both the server and the client

After doing all of those I finally have it working.

[mrdulin]

@sebght Try change version option for getSignedUrl method from v2(default) to v4