[whatwg] Enhancement request: change EventSource to allow cross-domain access

[Jonas Sicking]

On Mon, Jun 20, 2011 at 3:57 AM, Anne van Kesteren <annevk at opera.com> wrote:
> On Mon, 20 Jun 2011 12:53:02 +0200, Jonas Sicking <jonas at sicking.cc> wrote:
>>
>> On Mon, Jun 20, 2011 at 3:22 AM, Anne van Kesteren <annevk at opera.com>
>> wrote:
>>>
>>> Agreed. I can add that to CORS. I already added Last-Event-ID for that
>>> reason, but somehow missed Cache-Control.
>>
>> Wait, we don't have to add any headers to the CORS spec just because
>> implementations of various specs needs to send those without doing
>> preflight. The list of "simple headers" only affects which headers the
>> *page* can immediately set without a preflight being required, for
>> example through features like XMLHttpRequest.setRequestHeader.
>>
>> Headers that the implementation adds doesn't need to be added to this
>> list. For example the "Host" header is set by the browser in almost
>> all situations, but it does not need to be added to the list of
>> "simple headers". Indeed, adding in there would an out right bad idea.
>>
>> So I'm not convinced that the Last-Event-ID header needs to be in the
>> list.
>
> We could add Host as authors cannot set that anyway. But what you say makes
> sense. I will remove Last-Event-ID and add a note about how that list works.

One thing to keep in mind though is that in the case of XHR, the
Content-Type header is often in direct control of the page, even
through means other than setRequestHeader. For example by creating a
Blob with a specific content type using the .slice method.

/ Jonas