Hi David,
On 4/19/2015 9:51 AM, David Vanderson wrote:
On 04/18/2015 12:34 PM, George Neuner wrote:
However, to do this, I have to keep the initial id listacross
multiple requestsand thatis where I've run into trouble. Thus far, I
haven't had to use web server continuations. It seems like
send/suspend does not allow the browser to provideadditional
arguments (like paging direction).
The trick with using the continuations is you don't pass any arguments
through the url. All information is stored in local variables that
are captured automatically by the continuation. The url will be
generated for you, it just points to a continuation stored on the
server. Does that make sense? It's hard to wrap your brain around at
first.
I understand continuations in Scheme - it's the mechanism of this
URL/dispatch that I'm having a slight problem with. (see below)
send/suspend/dispatch looks like it will do what I want, however
Ineed to communicate the URLs to the browser in JSONand it
(superficially) appears as if embed/url is meant to work in generated
HTML?
Youneed to use a different response function.See theattached codefor
an example.Look at the docs for 'response/xexpr' to see what it does.
I know I need a different response function. The question was whether
embed/url is tied to HTML or can be used in a different context. The
documentation (6.1.1) says:
"When used inside page
<mailbox:///C:/Users/GW/Documents/Eudora/local/Mail/Local%20Folders/Drafts?number=0&part=1.2.2&filename=page.html>
syntactically, a rename transformer for the procedure embedding
function; otherwise, a syntax error."
That suggests embed/url can be used only in (X)HTML responses and that
I need to use something else to create dispatch URLs in regular code.
The final problem is how to ensure that I eventually get to
send/finishand clean up my thread. This particular function is
expected to be executed quite often. Does the browser app have to
invoke a URL that deliberately ends the thread or will the thread end
if/whenits continuations timeout?
What do you need to clean up? To be clear, there isn't a thread that
keeps running - the continuation is just some data, and like Jay said,
it will eventually be cleaned up. If you want to remove the
continuations manually, call send/forward or send/finish. See the
attached code. In particular, try running it, and then copying the
url to a second browser window. You'll see how two users have
different continuations.
My understanding is that serve/servlet executes dispatched functions in
separate threads. And I do see server multi-threading in practice -
e.g., a quick sequence of XHR calls made by the browser finishing in
different order. Timestamped in my application log as well as seen at
the browser.
So when I send/suspend* there will be a thread left suspended. Will
that thread context be cleaned up if the continuation expires? And can
I get a notification of which thread is involved? Or better yet, get
the thread restarted at yet another point so I can log that it has
finished processing. Are the threads just nuked invisibly or are they
terminated by an exception that I can catch?
George
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