Re: More UserMediaError codes (Re: NavigatorUserMediaError - numeric?)

On 08/29/2012 06:51 PM, Paul Neave wrote:
> On Wednesday, 29 August 2012 at 17:29, Harald Alvestrand wrote:
>> I found this note in the WebRTC WG archive from May 2012, so it's a
>> while ago.... thanks for bringing it back!
> Glad to bring attention back to this again!
>   
>> I have created [ACTION-9] to track this issue, and provisionally
>> assigned it to me.
>>
>> The concern I've seen raised before with detailed error messages is that
>> it allows probing to identify the user (you probe for a camera that he
>> might or might not have), but information about whether the user or the
>> system rejected the call is easily visible from timing anyway, so
>> returning an error might be good for the Good Guys while not giving
>> anything new to the Bad Guys.
> Yep, I can see that we don't want to give too much away if it can be helped.
>   
>> So I make it
>>
>> "permission denied" - user said no
>> "not available" - there is a device, but it is doing something else
>> "not supported" - no device satisfies the constraints
> This sounds right, nice and simple. A discussion on the Chromium project came to similar conclusions:
>
> http://code.google.com/p/chromium/issues/detail?id=132812
>
> Similarly:
> 1) "permission denied" - User pressed deny
> 2) "not available" - Mandatory devices not found or exclusively opened elsewhere
> 3) "not supported" - If a web browser wants to implement the API for compatibility reasons but not implement it
>
>
> There was also a suggestion for another constant:
> 4) "not allowed" - For example calling getUserMedia from a HTML file on the local file system
>
> Although here I think 4) is not completely necessary as 3) would probably suffice.
>
One could also argue that "permission denied" is appropriate when it's 
denied by policy - I run my test chromium with 
--allow-file-access-from-file, which makes this particular denial go 
away....

Received on Thursday, 30 August 2012 09:02:23 UTC