helma.org/wiki/Continuations

Version 26

hannes — Thu, 03 Apr 2008 23:32:09 +0200

65	As of 20072008/02/08, serialization issues in combination with Continuations and Javascript functions in general have been fixed in Subversion, so it's no longer a problem to use continuations in combination with persistent sessions.

Version 25

hannes — Mon, 18 Feb 2008 16:17:26 +0100

While adding continuation and callback support to existing Helma releases has been a bit of a hack, recent Helma snapshots have added features to make that easier, namely the introduction of *req.uri|https://dev.helma.org/trac/helma/changeset/8774* and *req.actionProcessoractionHandler|https://dev.helma.org/trac/helma/changeset/87758792*.

Version 24

hannes — Fri, 08 Feb 2008 17:03:16 +0100

An area that still needs work is serialization supportAs of 2007/02/08, as continuations currently will not work serialization issues in conjunction combination with persistent sessions. Persistent HopObjects shouldn't be included in a serialized continuation, so we need to convert Nodes into NodeHandles in the output stream, Continuations and convert back to Nodes Javascript functions in the input stream. The latter currently fails general have been fixed in session restore because it requires a Transactor thread.Subversion, For global references we need to make sure theyso it're excluded from serialization. Helma 1.7 seems like s no longer a good timeframe problem to fix these issuesuse continuations in combination with persistent sessions.

Version 23

hannes — Tue, 05 Feb 2008 17:49:18 +0100

41	This action displays three pages: the first renders a form, the second a link, and the third will show a message containing the string entered in the first page. Remember that for continuatino continuation support to work, you must call Continuation.resume() in onRequest():

Version 22

hannes — Tue, 05 Feb 2008 17:45:10 +0100

22
23	And although continuations work best with POST forms and ordinary links, if you must use GET forms, there also is:
24

Version 21

hannes — Tue, 05 Feb 2008 17:41:01 +0100

38	This action displays three pages: the first renders a form, the second a link, and the third will show a message containing the string entered in the first page. Remember that for continuatino support to work, you must call Continuation.resume() in onRequest():
40	function onRequest() {
41	Continuation.resume();
42	}
43

Version 20

hannes — Tue, 05 Feb 2008 17:29:49 +0100

22	* Continuation.nextId() - returns the ID for the next contiuation for cases GET forms where it isn't possible to use Continuation.nextUrl() and the continuation_id has to be set via hidden input field (GET requests)field.

Version 19

hannes — Tue, 05 Feb 2008 17:24:13 +0100

17	This adds four the following static methods to the Continuation constructor:
19	* Continuation.nextId() - returns the ID for the next contiuation for cases where it isn't possible to use Continuation.nextUrl() and the continuation_id has to be set via hidden input field (GET requests).
23	* Continuation.nextId() - returns the ID for the next contiuation for cases where it isn't possible to use Continuation.nextUrl() and the continuation_id has to be set via hidden input field (GET requests).

Version 18

hannes — Tue, 05 Feb 2008 17:23:15 +0100

19	* Continuation.nextId() - returns the ID for the next contiuation for cases where it isn't possible to use Continuation.nextUrl() and the continuation_id has to be set via hidden input field (namely GET requests, as Continuation.nextUrl()).
20	* Continuation.nextUrl() - returns the URL to the next continuation of the currently running action to be used in HTML POST forms and links. Note that the continuation doesn't exist yet until Continuation.nextPage() is called.

Version 17

hannes — Tue, 05 Feb 2008 17:21:48 +0100

17	This adds three four static methods to the Continuation constructor:
19	* Continuation.nextId() - returns the ID for the next contiuation for cases where it isn't possible to use Continuation.nextUrl() (namely GET requests, as Continuation.nextUrl()).

Version 16

hannes — Tue, 05 Feb 2008 17:18:15 +0100

50	res.debug("continuation Continuation invalid or expired. starting Starting over.");
52	// ...Continue rendering first page

Version 15

hannes — Tue, 05 Feb 2008 17:17:32 +0100

47	// Request has a continuation_id, but we landed at the beginning
50	/res.debug(/"continuation invalid or expired. Do what needs to be donestarting over.");
54	// From now here on, req.data.continuation_id is expected to be set

Version 14

hannes — Tue, 05 Feb 2008 17:05:01 +0100

7	Rhino continuations only work in interpreter mode with the compiler disabled, i.e. with optlevel -1so make sure that you have the following in your app.properties:
9	rhino.optlevel = -1
10

Version 13

hannes — Tue, 05 Feb 2008 16:55:58 +0100

This has the great benefit that trying to run a non-existing continuation (either because the link has been passed outside the originating session, or because the session has expired, or because the client does not support cookies) will actually result in the right page action being invoked - it will simply result in the action to be started from the beginning. So in order to detect all these cases, it is sufficient to test for a <code>continuation_id</code> parameter at the very beginning of the action:

Version 12

hannes — Tue, 05 Feb 2008 16:31:59 +0100

17	* Continuation.nextUrl() - This returns the URL to the next continuation of the currently running action to be used in HTML forms and links. Note that the continuation doesn't exist yet until Continuation.nextPage() is called.
18	* Continuation.nextPage() - This actually suspends execution and stores the suspended action in the user's session.
19	* Continuation.resume() - This must be called in the onRequest() method of the current object in order to allow the continuation to be resumed.

Version 11

hannes — Tue, 05 Feb 2008 16:29:59 +0100

24	res.write(<form method="post" action={ Continuation.nextUrl() }>

Version 10

hannes — Tue, 05 Feb 2008 16:28:49 +0100

This has the great benefit that trying to run a non-existing continuation (either because the link has been passed outside the originating session, or because the session has expired, or because the client does not support cookies) will actually result in the right page being invoked - it will simply result in the action to be started from the beginning. So in order to detect all these cases, it is sufficient to test for a <code>continuation_id</code> parameter at the very beginning of the action:

Version 9

hannes — Tue, 05 Feb 2008 16:28:02 +0100

17	* Continuation.nextUrl() - This returns the URL to the next continuation of the currently running action. The URL can action to be used in HTML forms and links. Note that the continuation doesn't exist yet until Continuation.nextPage() is called.
37	When running the example, you will notice that the continuations have the same URI path as the original action, just with a <code>continuation_id</code> query parameter added. This has the great benefit that trying to run a non-existing continuation (either because the link has been passed outside the originating session, or because the session has expired, or because the client does not support cookies) will actually result in the right page being invoked - it will simply result in the action to be started from the beginning. So in order to detect all these cases, it is sufficient to test for a <code>continuation_id</code> parameter at the beginning of the action:
39	/test.continuation?continuation_id=at5fgn5zz18g
40
41	This has the great benefit that trying to run a non-existing continuation (either because the link has been passed outside the originating session, or because the session has expired, or because the client does not support cookies) will actually result in the right page being invoked - it will simply result in the action to be started from the beginning. So in order to detect all these cases, it is sufficient to test for a <code>continuation_id</code> parameter at the beginning of the action:
42

Version 8

hannes — Tue, 05 Feb 2008 16:25:18 +0100

43	// or the link comes from another session. Do what needs
44	// Do what needs to be done.

Version 7

hannes — Tue, 05 Feb 2008 16:24:50 +0100

39	function continuation_action() {
40	if (req.data.continuation_id) {
41	// Request has a continuation_id, but we landed at the
42	// beginning of the action. Either the session timed out,
43	// or the link comes from another session. Do what needs
44	// to be done.
45	}
46	// ...
47	Continuation.nextPage();
48	// From now on, req.data.continuation_id is expected to be set
41	// ...
42	Continuation.nextPage();
43	// From now on, req.data.continuation_id is expected to be set
44	}

Version 6

hannes — Tue, 05 Feb 2008 16:23:58 +0100

11	The following framework makes use of these features script is a first prototype for adding Continuation support to allow storing suspended functions in the user's session object and resuming them at a later time:Helma 1.7 web framework.
15	This adds three static methods to the Continuation constructor:
16
17	* Continuation.nextUrl() - This returns the URL to the next continuation of the currently running action. The URL can be used in HTML forms and links.
18	* Continuation.nextPage() - This actually suspends execution and stores the suspended action in the user's session.
19	* Continuation.resume() - This must be called in the onRequest() method of the current object in order to allow the continuation to be resumed.
20
30	This action displays three pages: the first renders a form, the second a link, and the third will show a message containing the string entered in the first page.
31
32	When running the example, you will notice that the continuations have the same URI path as the original action, just with a <code>continuation_id</code> query parameter added. This has the great benefit that trying to run a non-existing continuation (either because the link has been passed outside the originating session, or because the session has expired, or because the client does not support cookies) will actually result in the right page being invoked - it will simply result in the action to be started from the beginning. So in order to detect all these cases, it is sufficient to test for a <code>continuation_id</code> parameter at the beginning of the action:
33
34	function continuation_action() {
35	if (req.data.continuation_id) {
36	// Request has a continuation_id, but we landed at the
37	// beginning of the action. Either the session timed out,
38	// or the link comes from another session. Do what needs
39	// to be done.
40	}
41	// ...
42	Continuation.nextPage();
43	// From now on, req.data.continuation_id is expected to be set
44	}