Azure Blob always downloads when navigating to url

Question

In our application we give the user the abilty to upload a document to a windows azure blob storage account. After uploading the document or image it gets assigned some url (https://name.blob.core.windows.net/container/file-name.jpg). If the document is an image or a pdf or some file that can be rendered by the browser we are trying to display it in the browser without requiring the user to download the file. If we just open up a new window or tab and direct the user to the blob uri in IE, the image or pdf renders correctly in the browser. But, if we try to just open a new window pointing to the uri in Chrome, FireFox, or Safari, it just downloads the file instead of displaying it in the browser.

Is there a way to force the latter three browsers to just display the file instead of download it?

Answer 1

   blob.Properties.ContentType = "application/pdf";

//Get the content type of the file by extension

    public static string GetFileContentType(string FilePath)
    {
        string ContentType = String.Empty;
        string Extension = Path.GetExtension(FilePath).ToLower();

        switch (Extension)
        {
            case ConstantUtility.FILE_EXTENSION_PDF:
                ContentType = "application/pdf";
                break;
            case ConstantUtility.FILE_EXTENSION_TXT:
                ContentType = "text/plain";
                break;
            case ConstantUtility.FILE_EXTENSION_BMP:
                ContentType = "image/bmp";
                break;
            case ConstantUtility.FILE_EXTENSION_GIF:
                ContentType = "image/gif";
                break;
            case ConstantUtility.FILE_EXTENSION_PNG:
                ContentType = "image/png";
                break;
            case ConstantUtility.FILE_EXTENSION_JPG:
                ContentType = "image/jpeg";
                break;
            case ConstantUtility.FILE_EXTENSION_JPEG:
                ContentType = "image/jpeg";
                break;
            case ConstantUtility.FILE_EXTENSION_XLS:
                ContentType = "application/vnd.ms-excel";
                break;
            case ConstantUtility.FILE_EXTENSION_XLSX:
                ContentType = "application/vnd.openxmlformats-officedocument.spreadsheetml.sheet";
                break;
            case ConstantUtility.FILE_EXTENSION_CSV:
                ContentType = "text/csv";
                break;
            case ConstantUtility.FILE_EXTENSION_HTML:
                ContentType = "text/html";
                break;
            case ConstantUtility.FILE_EXTENSION_XML:
                ContentType = "text/xml";
                break;
            case ConstantUtility.FILE_EXTENSION_ZIP:
                ContentType = "application/zip";
                break;
            default:
                ContentType = "application/octet-stream";
                break;

        }


        return ContentType;
    }

Use this to set the content type of the blob while saving it.

Set Content-type of media files stored on Blob

Answer 2

For those uploading files via PowerShell, use the below syntax to set content type during the upload.

Set-AzureStorageBlobContent -File <localFilePath> -Container <containerName> -Properties @{"ContentType"="text/plain"} -Context $ctx

Above I set the blob content type to text/plain, useful when uploading JSON and HTML files that will be used with templates. List of more content types header values here.

Answer 3

If using the Azure SDK (12.x+) there is a change that requires the use of BlobHttpHeaders that pass in to the upload method (instead of blob.Properties.ContentType).

For example:

    var header = new BlobHttpHeaders();
    header.ContentType = "image/jpeg";

    var response = await blobClient.UploadAsync(stream, header);

Answer 4

public String sasURL(String filePath) throws URISyntaxException, StorageException, InvalidKeyException {
    CloudBlockBlob cloudBlockBlob = cloudBlobContainer.getBlockBlobReference(filePath);
    SharedAccessBlobPolicy sasPolicy = new SharedAccessBlobPolicy();
    GregorianCalendar calendar = new GregorianCalendar();
    calendar.add(Calendar.HOUR, 3);
    sasPolicy.setSharedAccessExpiryTime(calendar.getTime());
    sasPolicy.setPermissions(EnumSet.of(SharedAccessBlobPermissions.READ, SharedAccessBlobPermissions.LIST));
    SharedAccessBlobHeaders sharedAccessBlobHeaders = new SharedAccessBlobHeaders();
    sharedAccessBlobHeaders.setContentType(MediaType.APPLICATION_PDF_VALUE);
    String sas = cloudBlockBlob.generateSharedAccessSignature(sasPolicy, sharedAccessBlobHeaders,null);
    return cloudBlockBlob.getUri()+"?"+sas;
}