Cloud API with JavaScript (Amazon, Azure)

Question

I\'m researching a possibility of using some cloud storage directly from client-side JavaScript. However, I ran into two problems:

1. Security - t

Answer 1

Windows Azure Blob Storage has the notion of a Shared Access Signature (SAS) which could be issued on the server-side and is essentially a special URL that a client could write to without having direct access to the storage account API key. This is the only mechanism in Windows Azure Storage that allows writing data without access to the storage account key.

A SAS can be expired (e.g., give user 10 minutes to use the SAS URL for an upload) and can be set up to allow for canceling access even after issue. Further, a SAS can be useful for time-limited read access (e.g., give user 1 day to watch this video).

If your JavaScript client is also running in a browser, you may indeed have cross-domain issues. I have two thoughts - neither tested! One thought is JSONP-style approach (though this will be limited to HTTP GET calls). The other (more promising) thought is to host the .js files in blob storage along with your data files so they are on same domain (hopefully making your web browser happy).

The "real" solution might be Cross-Origin Resource Sharing (CORS) support, but that is not available in Windows Azure Blob Storage, and still emerging (along with other HTML 5 goodness) in browsers.