Uploading blockblob and setting contenttype

问题

I'm using Microsoft.WindowsAzure.Storage.* library from C#.

This is how I'm uploading things to storage:

// Store in storage
CloudStorageAccount storageAccount = CloudStorageAccount.Parse("...connection string...");
CloudBlobClient blobClient = storageAccount.CreateCloudBlobClient();
CloudBlobContainer container = blobClient.GetContainerReference("pictures");

// Create container if it doesnt exist
container.CreateIfNotExists();

// Make available to everyone
container.SetPermissions(new BlobContainerPermissions
{
    PublicAccess = BlobContainerPublicAccessType.Blob
});

// Save image
CloudBlockBlob blockBlob = container.GetBlockBlobReference("blah.jpg");
blockBlob.UploadFromByteArray(byteArrayThumbnail, 0, byteArrayThumbnail.Length);
blockBlob.Properties.ContentType = "image/jpg";  // *** NOT WORKING ***

All the things I upload to the storage are being saved with content type "application/octet-stream", even though I'm using the setter with value "image/jpg" (see the last line in my code).

So question #1: Why isn't working the ContentType setter?

And question #2: If I manually change the content type to "image/jpg", using Windows Azure management portal, and then copy the absolute URI of the file to the browser's address field, and press enter, the jpg file is downloaded instead of displayed. Isn't this mime type supposed to be displayed instead of downloaded? How do I change this?

回答1:

Actually you don't have to call SetProperties method. In order to set content type while uploading the blob, just set the ContentType property before calling the upload method. So your code should be:

// Save image
CloudBlockBlob blockBlob = container.GetBlockBlobReference("blah.jpg");
blockBlob.Properties.ContentType = "image/jpg";
blockBlob.UploadFromByteArray(byteArrayThumbnail, 0, byteArrayThumbnail.Length);

and that should do the trick.

回答2:

After you make any changes to Properties, you have to make a call to CloudBlockBlob.SetProperties() to actually save those changes.

Think of it as something similar to LINQ-to-Entities. You can make any changes you want to your local object, but until you call SaveChanges(), nothing is actually saved.

回答3:

with the new version of the Azure Blob SDK this is no longer working.

this worked for me:

CloudBlockBlob blockBlob = cloudBlobContainer.GetBlockBlobReference(blobName);
blockBlob.Properties.ContentType = contentType;                            
await blockBlob.SetPropertiesAsync();

来源：https://stackoverflow.com/questions/24621664/uploading-blockblob-and-setting-contenttype