One thing about postMessage that I'm curious about. Since it has to report failure synchronously by throwing an INVALID_STATE_ERR, that seems to imply that all data must be written to a socket before returning and cannot be asynchronously delivered to an I/O thread without adding some risk of silently dropping messages. Seems like the right choice would be to allow outbound messages to drop, which would mean that developers would be forced to do their own handshaking.<div>
<br></div><div>I'm also not sure there is good coverage of error conditions in the spec. The only methods of error notification are exceptions in postMessage and onclose. I had assumed that a WebSocket that fails to connect would invoke onclose asynchronously, but I didn't see that in the spec. Without that you don't even have the ability to know if a socket failed to establish a connection (short of readyState polling). The spec also doesn't indicate that the readyState should transition to CLOSED on connection failure. (Description of the disconnect() method is careful to mention that it closes a connection or a connection attempt, but description of when onclose is fired just mentions a connection closing). I definitely think there should be a way to receive an event if a connection fails to establish; I would hate to have to poll another readyState.</div>
<div><br></div><div>/kel</div><div><br></div><div><div class="gmail_quote">On Fri, Jun 26, 2009 at 1:34 PM, Drew Wilson <span dir="ltr"><<a href="mailto:atwilson@google.com">atwilson@google.com</a>></span> wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex;"><div>Yes, but the "closed" state of a given WebSocket doesn't have to exactly match the state of the underlying TCP connection, in the same way that document.cookies doesn't exactly match the current set of cookies that the network stack may be tracking (they can differ when HTTP responses are received in the background while JS is executing).</div>
<div><br></div><div>So if the remote server closes the TCP connection, it generates a "close" event which marks the WebSocket as closed. It means that you could have a situation where you post messages to a WebSocket which aren't received by the server because the connection is closed, but that's true regardless due to the asynchronous nature of the networking protocol.</div>
<div><br></div><div>-atw</div><div><div></div><div class="h5"><div><br><div class="gmail_quote">On Fri, Jun 26, 2009 at 9:52 AM, Darin Fisher <span dir="ltr"><<a href="mailto:darin@chromium.org" target="_blank">darin@chromium.org</a>></span> wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
<div><div></div><div><div class="gmail_quote">On Fri, Jun 26, 2009 at 9:46 AM, Drew Wilson <span dir="ltr"><<a href="mailto:atwilson@google.com" target="_blank">atwilson@google.com</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
<div><br><div class="gmail_quote">On Fri, Jun 26, 2009 at 9:18 AM, James Robinson <span dir="ltr"><<a href="mailto:jamesr@google.com" target="_blank">jamesr@google.com</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
<span style="font-family:arial, sans-serif;font-size:13px;border-collapse:collapse"><div>However, users can't usefully check the readyState to see if the WebSocket is still open because there are not and cannot be any synchronization guarantees about when the WebSocket may close. </div>
<div><br></div></span></blockquote><div> </div></div></div>Is this true? Based on our prior discussion surrounding cookies, it seems like as a general rule we try to keep state from changing dynamically while JS code is executing for exactly these reasons.
</blockquote></div><br><div><br></div></div></div><div>I think this is a very different beast. The state of a network connection may change asynchronously whether we like it or not. Unlike "who" may access cookies or local storage, the state of the network connection is not something we solely control.</div>
<div><br></div><font color="#888888"><div>-Darin</div>
</font></blockquote></div><br></div>
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