Hash mismatch (integrity check failed) with Azure Blob Storage

Question

I'm following http://willi.am/blog/2014/07/03/azure-blob-storage-and-node-downloading-blobs/.

However despite the exact same code, when I download blobs Azure gives the error:

[Error: Hash mismatch (integrity check failed), Expected value is ...]

The line being run is blobService.getBlobToText, with blobService being the connection to Azure (createBlobService...)

What's going on? :S

My code's below:

    // Azure test
    function downloadImageAsText(blobService, containerName, blobName) {

         blobService.getBlobToText(
              containerName,
              blobName,
              function(err, blobContent, blob) {
                  if (err) {
                      console.error("Couldn't download blob %s", blobName);
                      console.error(err);
                  } else {
                      console.log("Sucessfully downloaded blob %s", blobName);
                      console.log(blobContent);
                  }
              });

    }

    function uploadImage(blobService, containerName, blobName, fileName) {

      blobService.getBlobProperties(
        containerName,
        blobName,
        function(err, properties, status) {
            if (status.isSuccessful) {
                // Blob exists
            } else {
                blobService.createBlockBlobFromLocalFile(
                    containerName,
                    blobName,
                    fileName,
                    function(error, result, response){
                        if(error){
                            console.log("Couldn't upload file %s", fileName);
                            console.error(error);
                        } else {
                            console.log('File %s uploaded successfully', fileName);
                            downloadImageAsText(blobService, containerName, blobName);
                        }
                    });
            }
        });
    }


    function testAzure() {

      accountName / hash = my details

      var storage = require('azure-storage');
      var blobService = storage.createBlobService(accountName, hash);
      var containerName = 'tst';
      var blobName = 'test.png';
      var fileName = 'test.png';

      blobService.createContainerIfNotExists(containerName, function(err, result, response) {
          if (err) {
              console.log("Couldn't create container %s", containerName);
              console.error(err);
          } else {
              if (result) {
                  console.log('Container %s created', containerName);
                  uploadImage(blobService, containerName, blobName, fileName);
              } else {
                  console.log('Container %s already exists', containerName);
                  uploadImage(blobService, containerName, blobName, fileName);
              }
          }
      });
    }

    function startServer() {
      http = require('http');
      const PORT = 8080;
      var server = http.createServer(handleRequest);
      server.on('listening',function(){
        console.log("Server listening on: http://178.62.117.207:%s", PORT);
      });
      server.listen(PORT);
    }

    startServer();
    testAzure();

Answer 1

In case someone else runs into this; happens when you store a Buffer object but retrieve a string.

Answer 2

Try something like the following (modifying the code from the blog post you mentioned):

var blobName = 'my-awesome-text-blob';
blobService.getBlobToText(
    containerName,
    blobName, {'disableContentMD5Validation': true },
    function(err, blobContent, blob) {
        if (err) {
            console.error("Couldn't download blob %s", blobName);
            console.error(err);
        } else {
            console.log("Sucessfully downloaded blob %s", blobName);
            console.log(blobContent);
        }
    });

See if this helps.

Answer 3

It can happen because of many internal MD5 check failures which works differently when you use HTTPS. Can you please try specifying your storage account as https? Like -

var blobService = storage.createBlobServiceAnonymous('https://MyAccountXX.blob.core.windows.net/');

Otherwise for me, this download function is working fine.

For reference, you can try following actual documentation - https://azure.microsoft.com/en-in/documentation/articles/storage-nodejs-how-to-use-blob-storage/

Answer 4

When you store a Buffer object, you can retrieve it with getBlobToStream.

const data: Buffer[] = [];
const stream = new PassThrough();

stream.on('data', (d: Buffer) => {
    data.push(d);
});

this.blobStorageContext.service.getBlobToStream(
    this.blobStorageContext.getContainerName(),
     blobName, stream, (error) => {
         if (error) {
           console.log(error);
         } else { 
           console.log(Buffer.concat(data));
         }
});

Answer 5

I've recently ran into this problem myself. Somehow npm -install azure-storage -g helped it. It might be that the package is updated on the npm and md5 calculation has changed since. Once I updated the azure-storage package, everything works like a charm.