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Re: [FileAPI] createObjectURL isReusable proposal

From: Tab Atkins Jr. <jackalmage@gmail.com>
Date: Wed, 14 Dec 2011 08:31:38 -0800
Message-ID: <CAAWBYDABg+hL-684=2BzpjvLKqW9kfSs=0LFXu5SCkRPUcAFYg@mail.gmail.com>
To: Adrian Bateman <adrianba@microsoft.com>
Cc: "Web Applications Working Group WG (public-webapps@w3.org)" <public-webapps@w3.org>, Feras Moussa <ferasm@microsoft.com>
On Tue, Dec 13, 2011 at 4:52 PM, Adrian Bateman <adrianba@microsoft.com> wrote:
> At TPAC [1,2] I described our proposal for adding an isReusable flag to
> createObjectURL. A common pattern we have seen is the need for a blob URL
> for a single use (for example, loading into an <img> element) and then
> revoking the URL. This requires a fair amount of boilerplate code to
> handle the load/error events.
>
> createObjectURL is modified as follows:
>
> static DOMString createObjectURL(Blob blob, [optional] bool isReusable);
>
> The value of isReusable defaults to true if it is not supplied and this
> results in the behaviour documented for File API today. However, if you
> supply false for the flag then the first dereference of the URL revokes it.
>
> This means that you can do something like:
>
> imgElement.src = URL.createObjectURL(blob,false)
>
> and not worry about having to call URL.revokeObjectURL to release the Blob.
>
> We have implemented this in experimental form in IE10 preview builds and
> it works well. There seemed to be a fair amount of support at TPAC and we're
> hoping this will be adopted in the File API spec.
>
> Thanks,
>
> Adrian.
>
> [1] http://www.w3.org/2011/11/01-webapps-minutes.html#item02
> [2] http://pages.adrianba.net/w3c/FilesAndStreams.pdf

I object to adding boolean flag arguments to any new APIs.  They're a
blight on the platform.  Further, baking non-essential arguments into
the argument list almost guarantees confusion down the line when
*more* options are added.

Please add this as an options object with a "reusable" property, like
"createObjectURL(blob, {reusable:false})" (or whatever name gets
decided on, like "single-use").

~TJ
Received on Wednesday, 14 December 2011 16:32:34 GMT

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