- From: Noah Mendelsohn <nrm@arcanedomain.com>
- Date: Sat, 14 May 2011 17:51:30 -0400
- To: "www-tag@w3.org" <www-tag@w3.org>
- CC: Arun Ranganathan <arun@mozilla.com>, Mark Nottingham <mnot@mnot.net>
FYI, from the uri@w3.org mailing list. Discussion should be held there, I think, at least for now. Noah -------- Original Message -------- Subject: Discussion of Blob URI Scheme for Binary Data Access | IETF Resent-Date: Fri, 13 May 2011 18:09:08 +0000 Resent-From: uri@w3.org Date: Fri, 13 May 2011 14:05:39 -0400 From: Arun Ranganathan <arun@mozilla.com> Reply-To: arun@mozilla.com Organization: Mozilla Corporation To: uri@w3.org Greetings URI listserv! I'm writing to this listserv at the behest of Mark Nottingham, who sent me here from the ietf-http-wg@w3.org listserv. This email is about a "new" URI scheme used to access binary data, and we'd like feedback on it, as well as advice on whether any further standardization endeavors are necessary. My name is Arun Ranganathan, and I'm the current editor of the File API [1] specification (sometimes called the HTML5 File API, which is unfortunate); I'm also the former Chair of the WebGL Working Group [2] (which brings hardware-accelerated 3D graphics to the web), and have a continued interest in allowing binary data to be securely accessed and manipulated on the web. I'm sponsored by Mozilla. The File API introduces the notion of a Blob object [3], which represents immutable binary data. A file from the underlying file system can be asynchronously read as a Blob object into various data formats, for example. The existing File interface in JavaScript inherits from Blob. Additionally, and most significantly for this listserv and this discussion, the File API introduces a URI scheme for Blob access [4]. The URI scheme uses a subset of the HTTP status codes, and is designed to be used wherever http URIs can be used within HTML markup and within APIs in JavaScript (e.g. for "img src =", alongside XMLHttpRequest, etc.). The nascent URL API [5] which coins and revokes blob: URIs is also used with the Stream API [6] for video-conferencing use cases, and thus this scheme is becoming integral to emerging technologies under the broad aegis of HTML. Browsers such as Chrome already implement blob: URIs [7]; Firefox's implementation will follow-suit, although is likely to be vendor-prefixed. Our goals are to address the shortcomings of the file:/// URI scheme, which many browsers support for directory browsing of the underlying file system, but for little else (file:/// URIs are unwise choices for APIs like XMLHttpRequest, don't supply response codes, etc.). The blob: scheme was designed to address the use case of dereferencing files and binary data on the web safely, since data: URIs have shortcomings as well, and can't really be used for streams of data. We'd welcome your feedback, including suggestions about whether embarking upon an IETF standardization track for this protocol is necessary. The File API will soon be initiating a CFC for Last Call status. -- A* [1] File API: http://dev.w3.org/2006/webapi/FileAPI/ [2] WebGL: http://www.khronos.org/webgl/ [3] Blob defintion: http://dev.w3.org/2006/webapi/FileAPI/#dfn-Blob [4] blob: URI scheme: http://dev.w3.org/2006/webapi/FileAPI/#url [5] URL API: http://dev.w3.org/2006/webapi/FileAPI/#creating-revoking [6] Stream API: http://www.whatwg.org/specs/web-apps/current-work/multipage/dnd.html#stream-api [7] Use of blob: URI scheme in demos: http://www.html5rocks.com/tutorials/workers/basics/#toc-inlineworkers-bloburis
Received on Saturday, 14 May 2011 21:51:55 UTC