RE: [Axiom-developer] RE: Mathaction edit/preview/save problem

[Bill Page]

William,

I am sorry for the length of this reply. Although I do not have
any immediate solution to your problem, I hope I have at least
explained some important things about MathAction below in response
to your questions and suggestions.  I would very much like to
make it possible for you to use MathAction since I do truly
believe that it would make it possible for you to write even more
interesting things then the things that you are already writing
about simply by email!

On Sunday, January 16, 2005 7:40 AM you wrote:
> 
> I went to the DynamicFunctionDomains page, select edit, 
> changed "shouldn't be::" to "shouldn't:" and preview.
> The bottom of the browser says: "Waiting for
> page.axiom-developer.org..." This has gone on for
> 5 minutes.

I just tried exactly the above steps. I am using Firefox 1.0 on
a 2.4 GHz 512 Mb Windows XP (SP2) machine networked to a Windows
98 machine running NAT32 firewall and connected to a Hughes
DirecPC-type satellite downlink and 56K outbound modem.

The preview responds correctly in approximately 15 seconds.

> 
> So clearly, it is not a DNS problem.

I agree that what you report is not a DNS problem.

> Then a pop up Alert window in the browser says: "The document
> contains no data." After I click OK, the  bottom message
> "waiting ..." goes away. I am back to the editing page.

It seems that your browser received a partial page and has
just given up waiting for the rest.

> 
> During all this period, the firewall records no blocked 
> transmissions (setting
> is on High). The browser is Firefox on Windows XP (SP2).

BTW, what version of Firefox are you running?

> 
> I went to Sandbox Main page, and edited the phrases to 
> "Edited again as a test". Preview works, Save works (and
> response was almost instantaneous, with saving a bit
> slower). In fact, the last time I changed this page, it 
> was forwarded to the mailing list. (Somehow, I thought
> Sandbox was just for testing and won't be reported).

Maybe that would be a good idea. I think it is possible for
the Zope manager account to change the default notification
options of individual pages, but I have not tried this yet.

Anyway, using Preview does not generate any notification and
that should be enough for testing. If Preview works then it
is quite certain that Save will work.

> 
> I have no problem uploading large files (or downloading) in 
> general. And the page DynamicFunctionDomains is not that large
> at all.
> 
> I can only report exactly what I saw. I don't understand how 
> these things work. If the error messages were different, it
> could be they were different, or it could be I was careless
> in reporting. But the above is as accurate as I can, for
> this report.

Thank you for the accurate report. Sometimes it is essential
to be excruciatingly accurate in order for someone else to
understand what might be causing the problem.

> 
> I don't want to randomly test other pages because if they 
> work, everyone gets the spurious reports on the changes.

I think all you need for a successful test is for Preview
to work. That will not generate any reports to other users.

> 
> Now, I am doing the same test on a Fedora FC2 machine. The 
> machine is a 1.4GHz Dell P4, and almost nothing else is running.
> Every configuration is default (I don't know how to configure
> Linux). Browser is Mozilla. It has been 5 minutes since the
> pressing the Preview button and finally this message: Bad Request.
> Your browser sent a request that this server could not understand.
> Apache/2.0.40 Server at axiom-developer.org Port 80. I did this
> twice, same thing. In fact, on cancel, the browser took a
> considerably longer time (10 minutes?) and returned also Bad Request!
> 
> On Fedora machine, I can't add a comment to IndexedVariables page
> either (Bad Request). Same thing for FiniteFieldExpressions page.
> On Windows IE, I was able to add a comment to ExternalEdit page,
> but I was not able to edit and remove it!
> (The Page cannot be displayed).

All of this still suggests to some serious network configuration
problem either at your location or perhaps at your ISP.

> 
> I am wondering whether it is because the page is locked 
> because someone else is editing the page before I start?

No. This would only happen if some simultaneously tried to
Save changes to the same page. In that case, one user will
receive a message saying that the page was locked. I am quite
sure that this does not apply to your current situation.

> I know XP locks files that are open, and Zope too.

No "file" is opened in a manner that would create a lock
when you do Preview.

> 
> Do I need to install Zope? (I have not).
> 

No. Zope only runs on the server.

> Bill Page wrote:
> 
> > Do you really get two different messages? Does which message
> > you get depend on some firewall setting? Do you get the same
> > message in both Microsoft Explorer and Firefox?
> 
> Just now, trying this on PrimeField page with IE, adding 
> "Taken from:" at the beginning, the message is "The page cannot
> be displayed". At the bottom, "Cannot find server or DNS Error"
> Internet Explorer.

I think that this really does mean that there is a "DNS Error"
:) A DNS Error is a problem that your ISP should correct. Usual
it is a problem with the ISP domain name server (DNS).

> 
> So I suppose you can say they are different on all three.
> 
> > "This page cannot be displayed" usually means that your
> > connection to the server is ok but that your browser received
> > something that it could not process. I have sometimes seen
> > this message if a web site takes a long time to reply. However
> > the correct message in that case should really be a "time out".
> 
> Since on the Fedora machine, it took over 5 minutes before 
> reporting "Bad Request", could that really be it takes so
> long to process the page?

No.

> Does the page call Axiom EVERY time it is opened?

No.

> (or only when it is changed)?

Yes, only when it is changed.

> 
> > > I just added Hello to the Sandbox MainPage. I went right to
> > > the DynamicFunctionDomains and change (4,7) to (4,8) and click
> > > preview. Then it stalls and same problem.
> > 
> > When you say "stalls", how long do you estimate you had to wait
> > before you received the "This page cannot be displayed" message?
> 
> I timed it to be about 5 minutes for the above for the Fedora 
> machine. Last time, it is about less but I did not time it.
> Also on IE it is less. But 5 minutes should be plenty, especially
> when I have no delays accessing the site for other than submitting
> a change or previewing it.

Yes I agree. Typical response time for me here at home is about
20 seconds. I work with a very high speed network connect but
complex firewall, the response time is about 10 seconds.

> 
> > > It seems to be a write privilege denied type of problem to me.
> > >
> > 
> > No there are no controls write privileges on any page on
> > MathAction except for just one page. 
> 
> What are the file privilege settings? Who are the owners of pages?

Your question presumes something which is not strictly true
for the way the MathAction wiki runs under Zope. Under Zope there
is not such thing as a "file" instead there are objects and methods
in a database that are "called" to create pages dynamically. The
concept of privilege is quite complicated but in general on MathAction
these settings allow anyone to change anything of a page and to create
new pages but only the site manager can delete pages.

In MathAction there is no concept of "ownership" of pages.

>  
> May be the pages are locked? or even the directory is?

No this is not the case.

> Zope External Editor page:
> Locks objects while they are being edited. Automatically 
> unlocks them when the editing session ends. 
> 
> If a page is locked, and someone else opens the page, does 
> the edit button work?
> (it should not).

This is a special case. But you are right that this can cause
the system to display the message saying that a page is "locked"
if another user attempts to Save changes to a page at the same
time that another users is using an External Editor to modify
the same page. An External Editor is invoked by first having
special software installed on your computer and then clicking
the little icon that looks like a pencil. If this is properly
setup they it is possible to edit pages using what ever text
editor your like (even Emacs :). The editable contents of the
page automatically appears in the editor that you specified
when you installed the External Editor package. And any changes
you make are automatically saved back to the MathAction page
when you exit the editor. But in this case there is no Preview
function.

If you click "edit" on the menu line the way you are doing now
then the editing takes place directly in your browser. The Preview
function only exists in this mode.

> ... 
> I just went to Sandbox Mainpage and edited it to call axiom 
> with 2+2. There is a slight delay in preview, but it worked and
> returns the answer 4. 

Well that is nice and that is exactly what it should do for you
for all pages on MathAction. If you try to make a change and to
Preview other pages do some work and some not? Can you see any
pattern?

This behaviour seems very strange but it could still be some
odd configuration problem at your ISP that only happens when
certain limits are exceeded.

> 
> > Is there any setting on your firewall software that might affect
> > the time your system waits for a reply?
> 
> All the time security is on High. I don't see how the firewall
> knows the difference between Sandbox Mainpage and the other pages!

I agree that the firewall cannot know the difference. The idea
I had was that perhaps your firewall can become "impatient" for
a response and perhaps drop data packets or other nasty things
if the network response is taking too long. But this is unlikely
based on other information that you have provided.

> For the same reasons, I don't see how my netgear box's firewall
> can make the distinction either. I used three different computers,
> OSes, and browsers already (from the same ISP of course).

I agree. The issue is only what happens when the web site does
not respond quickly.

> Is there nobody else experiencing this weird error?

I have not received any other reports regarding problems accessing
and changing the MathAction website. But then, it is true that a
very disappointing small number of people seem to be motivated to
make any changes even though it is open for everyone in the world
with a browser :( ... Martin Rubey is the only other person besides
myself who has made extensive changes to pages on MathAction. He
has not reported any problems.

> 
> > Is it possible for you to easily and temporarily turn off the
> > firewall software completely in order to see if that cures the
> > problem? If turning off the firewall works, then there is very
> > likely some setting in the firewall software that you can change
> > that will make it work without shutting it off.
> 
> Yes, I did and that made no difference. But I have to say, I 
> only turned off EZ Firewall. XP (SP2) has its own firewall setting
> that I won't know how to tweak. But as I said, I don't see how the
> firewall can detect differences in the two pages unless the two
> pages ARE different in their handling of Preview and Save buttons.

Yes I agree. The only differences I know of would be issues of
timing (how long the server takes to respond) and variations in
the content, like the number if images and the use of complicated
style sheets etc. Compared to most static web sites, the pages
generated by MathAction can be quite complex in structure.

> 
> > Finally, do you have a different location (such as office at
> > work versus at home) where you can try to access MathAction
> > and make this change? At least if you can confirm that it works
> > for you at one location but not at another then it might be
> > easier to determine what is different and what to change.
> 
> Yes, but I don't go to my office these days. But if I do, I'll
> give it a try. (However, even if that works, it is not going to
> help me since I do most of my work at home).
> 

After you are confident that it does work elsewhere, then the
best people to help you to get it to work at home would be the
technical support at your ISP.

Regards,
Bill Page.