seaside-dev July 2012

seaside-dev@lists.squeakfoundation.org

8 participants
5 discussions

cookie based sessions, RESTful urls no _k
by Nick Ager 22 Nov '12

22 Nov '12

Hi, In RESTful applications which also generate continuation key (_k) links a problem can arise if you open multiple tabs all sharing the same session. To illustrate: 1) Enable cookies for http://localhost:8080/examples/counter. 2) Open the counter and increment the value. 3) Open http://localhost:8080/examples/counter in a new tab and decrement the counter. 4) Return to the first counter and increment the value - you will see "-1" rather then "2" ! What I think is happening: If Seaside finds a session but there is no continuation key (_k) then WASession>>#handleFiltered: calls WARenderLoopMain>>#start which in turn creates a new root presenter and calls #initialRequest on the presenter. When the second tab is opened a new WACounter is created and stored in the session's #presenter property. When you return to the first tab, the callback is executed on the first counter, but the second counter is rendered. Ideas for possible fixes: * I thought that #presenter was backtracked so don't understand why the original counter #presenter isn't restored for the callback. If the presenter was backtracked correctly then the counter example should work as anticipated.... however: * in Pier (and potentially other RESTful apps) you don't want to create a new presenter for every RESTful call within an active session. If you don't create a new presenter then #initialRequest currently won't be called, which then won't allow your RESTful app to derive state from the url. If Seaside is modified to call #initialRequest do you need to differentiate between a call on a newly created session and one on an existing session? You could differentiate with a call to a new method on WAPresenter, pass in a flag to #initialRequest, or set a WARequestContext property to indicate a new session had been created. What to do with backtracked state. Do you nil all state before handling the request, restore state from a stored "initial value" snapshot or just use the state of the components from their last handled state? I bought this issue up before [1], but didn't pursue it as I was struggling to understand the issues and ran out of time. Julian responded to my previous email when I was proposing a problematic fix with: I'm not sure it's a good fix in the general case. If you don't have a > continuation key, you shouldn't (by definition) have any existing > (backtracked) state. Relying on the root presenter currently in the > Session is problematic since that value is backtracked for each > request; you'll simply get whichever root happened to be used by > whatever request was last handled by that session. If you don't happen > to be ever changing the root, then it may well be what you want, but > it's not right in the general case. > Incidentally, this also touches on the flaw I was discussing the other > week with our snapshots: because we have no continuation key, we > really ought to nil out any backtracked data before processing the > request (at least that way we have a consistent state while handling > the request). We don't run into the problem with the root presenter > because #start reinitializes it, but for other backtracked state, > you'd just get random stuff in there based on the last-handled > request. > A more appropriate general fix (at least in this case) could be to > take the last-used continuation and apply its state before handling a > request with no _k. However, we don't always know the last-used > (depending on the caching mechanism in place) and I'm not convinced > that is actually always what people want. I still feel pretty > confident that the "right" semantics of an Application/Session request > with no _k is to start a new main/render-loop. Certainly for Pier as it is currently designed I don't think that creating a new render-loop for session requests with the _k is the right thing to do, as it created a new root #presenter. I think ideally Seaside would for existing session with no _k 1) Keep the existing #presenter 2) call #initialRequest with a flag to indicate that a new session hadn't been created. 3) restore the state to an "initial render state" which is snapshotted (?) when the initial render occurs on a new session. Thoughts Nick [1] http://forum.world.st/sessions-continuation-keys-restful-urls-and-component… If each tabs starts with a RESTful url then a new presenter will be created.

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Dangling references in VisualWorks dev-build Jul12.3 Seaside framework
by Shaping Shaping 30 Jul '12

30 Jul '12

Hi. I've loaded all Seaside parcels delivered with VW dev build Jul12.3. These include all of the Seaside framework, all examples, and all tests. After, Undeclared contained references to HTTPWebTransport HTTPWebTransportConfiguration ODBCConnection OracleConnection SeasideMarshaler SeasideResponder I suppose that HTTPWebTransport should be HTTPTransport and that HTTPWebTransportConfiguration should be HTTPTransportConfiguration. Is that correct? ODBCConnection is referenced as a symbol used as a key to access the actual class, which is absent. Perhaps a parcel prereq should be updated here. OracleConnection is referenced in a CompiledMethod in an AbsentClassImport for Database.OracleSession. The source for the unloaded method is nonThreadedConnectionClass "Answer the connection class for sessions" ^OracleConnection SeasideMarshaler and SeasideResponder are both referenced in loaded methods. Did the author intend to refer to newer versions of these classes with different names? I got the same set of Undeclareds when I loaded all of Seaside from the Cincom Public repository. Have these problems been noticed and fixed by anyone? Shaping

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Inserting JQuerySVG plug in
by Lorenzo Schiavina 29 Jul '12

29 Jul '12

Hi, I am almost new to Seaside, but I have a very good knowledge of ST. I would like to use JQuerySVG plug in in Seaside: could you suggest me a detailed documentation that enables me to insert this plug in Seaside or there is anybody that has already done this work? Thanks Lorenzo

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Configuration of Seaside 3.0.7.1
by Johan Brichau 25 Jul '12

25 Jul '12

Hi everyone, I just noticed that latest ConfigurationOfSeaside pulls in an older KomHttpServer version. I.e.: it should pull in version 1.1.0 instead of 1.0.9 (or alternatively: the #stable version). I'm using Kom for SeasideTesting in Pharo1.4 and this bug makes the testcases misteriously fail (it doesn't bring up a decent debugger but fails). Any reason for not grabbing latest Kom? Johan

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Moving Seaside-REST from Addons to "Core" in 3.1
by Philippe Marschall 01 Jul '12

01 Jul '12

Hi I want to move Seaside-REST from Addons to the "Core" repository in Seaside 3.1: The reasons are the following: - the code base has stabilized and has been jürgenized by Lukas - we have documentation in the book [1] - several people use it I'm aware this will probably cause problems for some people but I don't think leaving it in addons or having it in both places are good alternatives either. Is this absolutely terrible or somebody (Dale?)? Personally I think of the addons repository as something similar to Apache Incubator. A place where we can experiment. If things turn out well we can graduate them to the core repository. [1] http://book.seaside.st/book/advanced/restful Cheers Philippe

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seaside-dev July 2012