XMLHttpRequest() and persistent connections

[David Given]

I have a web app, written in Javascript, that communicates to a back-end
server via XMLHttpRequest.

The logic goes:

* Login
* Perform transaction
* (delay while the user does something)
* Perform transaction
* ...
* Logout

It would be really convenient if I could make the whole thing a single HTTP
connection. That way, I avoid needing IPC and session management at the
server end, and a single instance of a CGI script can represent the entire
session. When the socket gets closed, the CGI script terminates and
implicitly logs the user off. All very simple.

Can I use HTTP pipelining with XMLHttpRequest to do this? The docs seem to
say (it's quite hard to tell) that I have to call open() after each send(),
which will presumably create a new HTTP session. Can I 'persuade' the
browser to reuse an existing session?

--
+- David Given --McQ-+
| [e-mail] | "I have a mind like a steel trap. It's rusty and
| ([e-mail]) | full of dead mice." --- Anonymous, on rasfc
+- www.cowlark.com --+

[Martin Honnen]

David Given wrote:

I have a web app, written in Javascript, that communicates to a back-end
server via XMLHttpRequest.

The logic goes:

* Login
* Perform transaction
* (delay while the user does something)
* Perform transaction
* ...
* Logout

It would be really convenient if I could make the whole thing a single HTTP
connection.

It might be that XMLHttpRequest in Mozilla has a feature for some time
now that could help, see
<https://bugzilla.mozilla.org/show_bug.cgi?id=237319>
that is fixed and added support for multipart/x-mixed-replace.
I haven't used that but what I have read there comes close to what you
describe above.
But given the limited implementations of XMLHttpRequest in Opera or
Safari so far I have doubts it will work there.
Not sure whether MSXML/IE can handle that.

Please report back to the group whether that multipart/x-mixed-replace
feature of XMLHttpRequest in Mozilla is useful for you.
--

Martin Honnen
http://JavaScript.FAQTs.com/

[David Given]

Martin Honnen wrote:
[...]

Please report back to the group whether that multipart/x-mixed-replace
feature of XMLHttpRequest in Mozilla is useful for you.

I've had a look at that; it allows the server to send multiple responses
back to the client down the same HTTP session, but I don't know if it
allows multiple two-way *transactions* down the same HTTP session.

--
+- David Given --McQ-+ "Apatheism: the school of belief where on doesn't
| [e-mail] | particularly care if there is/are god(s)." ---
| ([e-mail]) | Capt. Gym Z. Quirk
+- www.cowlark.com --+

[Martin Honnen]

David Given wrote:

Martin Honnen wrote:

Please report back to the group whether that multipart/x-mixed-replace
feature of XMLHttpRequest in Mozilla is useful for you.

it allows the server to send multiple responses
back to the client down the same HTTP session, but I don't know if it
allows multiple two-way *transactions* down the same HTTP session.

In my understanding the client with XMLHttpRequest will do one request
and then be able to receive multiple responses but indeed multiple
two-way exchange is not possible that way.
--

Martin Honnen
http://JavaScript.FAQTs.com/