[Zope] possible bug in zope 2.4.0/2.4.3 or 2.5.x

Sun, 31 Mar 2002 22:31:32 +0200

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Dear sirs,
=20
i'm a software developer from germany and actually writing a web-based
application. This application is based on zope, because in my opinion
zope is perfect for this. I've developed this application as a python
based product, the first version written in dtml was too slow.
Everything has worked fine, till I wanted to develop a new feature.
=20
In my application I'm using a server-based sessions-management, which
stores my object instances in a sessions-directory, which itself is
stored in the ZODB. Now one of these objects has a dictionary, which
stores multiple subobjects, for example the main object is a company,
which has subobjects representing contact-persons in this company. Now
I've written functions, which allow the user to add/change and remove
contact-persons for a company. To let this work, the companies object
with all the subobject is stored in the ZODB. Now the problem is, that
zope seems to forget the contents of the dictionary. You can add, remove
and change the subobjects, but suddenly the dictionary contains only
that subobjects, which where in at the beginning.
=20
Example:
The companies instance is stored into a ZODB Folder with the id
"Company10". Now this instance has a property "contacts", which has a
directory named "__items__". The contacts itself are represented by
another object, which instances are stored in contacts.__items__. So if
you call Company10, there are 3 contacts saved into __items__.
Company10.contacts.__items__{1:Contact Instance at ..., 2:Contact
Instance at..., 3:Contact Instance at ...}
You can now add, remove and change the contacts for the company, but
suddenly all changes made for the __items__ dictionary are lost. Maybe
you've deleted all of the initial instances, and added two new contacts,
your changes disappear and the dictionary contains only the initial
three contacts.
=20
I couldn't find out, why or when this is happening. BUT: if I start the
zope server in debug mode, everything is working fine !
=20
I started the development with zope 2.4.0, but even the update to 2.4.3
doesn't solved the problem. I've read all the changes made since 2.4.0
to 2.5.0, but I couldn't find an entry matching my problem.
=20
I then thought to pickle the objects myself and save them to the linux
filesystem. But it's not possible to pickle my objects, cause there are
references to the zope ZODB and the REQUEST object, which is obviously
not pickable.
=20
Do you know how to solve this problem ? I don't know, what to do else.
In general, the whole application is based on the mechanism, storing
objects and subobjects into the ZODB, cause HTTP is a connection-less
protocol.
=20
Thanks for your help in forward.
Yours=20
Marcus Ollas.=20
___________________________________________=20
     __=20
|   |  | \  /   LOXCOM=20
|   |  |  \/    digital services GmbH=20
|   |  |  /\    Weseler Str. 67-69=20
|__ |__| /  \   D-45721 Haltern=20
Marcus Ollas=20
Systems Engineering=20
Telefon: +49 (0) 2364 / 9238-94=20
Telefax: +49 (0) 2364 / 9238-90=20
Mobil:   +49 (0) 173 / 539 6150=20
Email:   mco@loxcom.net=20
___________________________________________=20
=20

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<div class=3DSection1>

<p class=3DMsoNormal><font size=3D2 face=3DArial><span lang=3DEN-GB =
style=3D'font-size:
10.0pt;font-family:Arial;mso-ansi-language:EN-GB'>Dear <span =
class=3DGramE>sirs</span>,<o:p></o:p></span></font></p>

<p class=3DMsoNormal><font size=3D2 face=3DArial><span lang=3DEN-GB =
style=3D'font-size:
10.0pt;font-family:Arial;mso-ansi-language:EN-GB'><o:p>&nbsp;</o:p></span=
></font></p>

i&#8217;m a software developer from =
<st1:country-region><st1:place>germany</=
st1:place></st1:country-region> and actually writing a web-based application. =
This
application is based on zope, because in my =
opinion zope is perfect for this. I&#8217;ve developed =
this
application as a python based product, the first version written in =
dtml was too slow. Everything has worked fine, =
till I wanted
to develop a new feature.<o:p></o:p>

<p class=3DMsoNormal><font size=3D2 face=3DArial><span lang=3DEN-GB =
style=3D'font-size:
10.0pt;font-family:Arial;mso-ansi-language:EN-GB'><o:p>&nbsp;</o:p></span=
></font></p>

In my application =
I&#8217;m
using a server-based sessions-management, which stores my object =
instances in a
sessions-directory, which itself is stored in the ZODB. Now one of these =
objects
has a dictionary, which stores multiple subobjects,
for example the main object is a company, which has subobjects
representing contact-persons in this company. Now I&#8217;ve written =
functions,
which allow the user to add/change and remove contact-persons for a =
company. To
let this work, the companies object with all =
the subobject is stored in the ZODB. Now the problem =
is, that zope seems to =
forget the contents
of the dictionary. You can add, remove and change the subobjects,
but suddenly the dictionary contains only that subobjects,
which where in at the beginning.<o:p></o:p>

<p class=3DMsoNormal><font size=3D2 face=3DArial><span lang=3DEN-GB =
style=3D'font-size:
10.0pt;font-family:Arial;mso-ansi-language:EN-GB'><o:p>&nbsp;</o:p></span=
></font></p>

<p class=3DMsoNormal><font size=3D2 face=3DArial><span lang=3DEN-GB =
style=3D'font-size:
10.0pt;font-family:Arial;mso-ansi-language:EN-GB'>Example:<o:p></o:p></sp=
an></font></p>

The companies instance =
is
stored into a ZODB Folder with the id &#8220;Company10&#8221;. Now this
instance has a property &#8220;contacts&#8221;, which has a directory =
named &#8220;__items__&#8221;.
The contacts itself are represented by another object, which instances =
are
stored in contacts.__items__. So if you call =
Company10,
there are 3 contacts saved into __items__.<o:p></o:p>

<p class=3DMsoNormal><font size=3D2 face=3DArial><span lang=3DEN-GB =
style=3D'font-size:
10.0pt;font-family:Arial;mso-ansi-language:EN-GB'>Company10.contacts.__it=
ems_<span
class=3DGramE>_{</span>1:Contact Instance at &#8230;, 2:Contact Instance =
at&#8230;,
3:Contact Instance at &#8230;}<o:p></o:p></span></font></p>

You can now add, remove and change the contacts for the company, =
but
suddenly all changes made for the __items__ dictionary are lost. Maybe =
you&#8217;ve
deleted all of the initial instances, and added two new contacts, your =
changes disappear
and the dictionary contains only the initial three =
contacts.<o:p></o:p>

<p class=3DMsoNormal><font size=3D2 face=3DArial><span lang=3DEN-GB =
style=3D'font-size:
10.0pt;font-family:Arial;mso-ansi-language:EN-GB'><o:p>&nbsp;</o:p></span=
></font></p>

I couldn&#8217;t find =
out, why
or when this is happening. BUT: if I start the zope
server in debug mode, everything is working fine =
!<o:p></o:p>

<p class=3DMsoNormal><font size=3D2 face=3DArial><span lang=3DEN-GB =
style=3D'font-size:
10.0pt;font-family:Arial;mso-ansi-language:EN-GB'><o:p>&nbsp;</o:p></span=
></font></p>

I started the =
development
with zope 2.4.0, but even the update to =
2.4.3 doesn&#8217;t
solved the problem. I&#8217;ve read all the =
changes
made since 2.4.0 to 2.5.0, but I couldn&#8217;t find an entry matching =
my
problem.<o:p></o:p>

<p class=3DMsoNormal><font size=3D2 face=3DArial><span lang=3DEN-GB =
style=3D'font-size:
10.0pt;font-family:Arial;mso-ansi-language:EN-GB'><o:p>&nbsp;</o:p></span=
></font></p>

I then thought to =
pickle the
objects myself and save them to the linux =
filesystem. But it&#8217;s not possible to pickle =
my
objects, cause there are references to the =
zope ZODB and the REQUEST object, which is =
obviously not pickable.<o:p></o:p>

<p class=3DMsoNormal><font size=3D2 face=3DArial><span lang=3DEN-GB =
style=3D'font-size:
10.0pt;font-family:Arial;mso-ansi-language:EN-GB'><o:p>&nbsp;</o:p></span=
></font></p>

Do you know how to =
solve this
problem ? I don&#8217;t know, what to do =
else. In
general, the whole application is based on the mechanism, storing =
objects and subobjects into the ZODB, cause
HTTP is a connection-less protocol.<o:p></o:p>

<p class=3DMsoNormal><font size=3D2 face=3DArial><span lang=3DEN-GB =
style=3D'font-size:
10.0pt;font-family:Arial;mso-ansi-language:EN-GB'><o:p>&nbsp;</o:p></span=
></font></p>

<p class=3DMsoNormal><font size=3D2 face=3DArial><span lang=3DEN-GB =
style=3D'font-size:
10.0pt;font-family:Arial;mso-ansi-language:EN-GB'>Thanks for your help =
in
forward.<o:p></o:p></span></font></p>

<p><font size=3D2 face=3D"Courier New"><span lang=3DEN-GB =
style=3D'font-size:10.0pt;
font-family:"Courier =
New";mso-ansi-language:EN-GB;mso-no-proof:yes'>Marcus
Ollas</span></font><span lang=3DEN-GB =
style=3D'mso-ansi-language:EN-GB;mso-no-proof:
yes'> <br>
</span><font size=3D2 face=3D"Courier New"><span lang=3DEN-GB =
style=3D'font-size:10.0pt;
font-family:"Courier =
New";mso-ansi-language:EN-GB;mso-no-proof:yes'>Systems
Engineering</span></font><span lang=3DEN-GB =
style=3D'mso-ansi-language:EN-GB;
mso-no-proof:yes'> <o:p></o:p></span></p>

<p><font size=3D2 face=3D"Courier New"><span lang=3DEN-GB =
style=3D'font-size:10.0pt;
font-family:"Courier =
New";mso-ansi-language:EN-GB;mso-no-proof:yes'>Telefon:
+49 (0) 2364 / 9238-94</span></font><span lang=3DEN-GB =
style=3D'mso-ansi-language:
EN-GB;mso-no-proof:yes'> <br>
</span><font size=3D2 face=3D"Courier New"><span lang=3DEN-GB =
style=3D'font-size:10.0pt;
font-family:"Courier =
New";mso-ansi-language:EN-GB;mso-no-proof:yes'>Telefax:
+49 (0) 2364 / 9238-90</span></font><span lang=3DEN-GB =
style=3D'mso-ansi-language:
EN-GB;mso-no-proof:yes'> <br>
</span><font size=3D2 face=3D"Courier New"><span lang=3DEN-GB =
style=3D'font-size:10.0pt;
font-family:"Courier =
New";mso-ansi-language:EN-GB;mso-no-proof:yes'>Mobil:&nbsp;&nbsp;
+49 (0) 173 / 539 6150</span></font><span lang=3DEN-GB =
style=3D'mso-ansi-language:
EN-GB;mso-no-proof:yes'> <br>
</span><font size=3D2 face=3D"Courier New"><span lang=3DEN-GB =
style=3D'font-size:10.0pt;
font-family:"Courier =
New";mso-ansi-language:EN-GB;mso-no-proof:yes'>Email:&nbsp;&nbsp;
mco@loxcom.net</span></font><span lang=3DEN-GB =
style=3D'mso-ansi-language:EN-GB;
mso-no-proof:yes'> <br>
</span><font size=3D2 face=3D"Courier New"><span lang=3DEN-GB =
style=3D'font-size:10.0pt;
font-family:"Courier =
New";mso-ansi-language:EN-GB;mso-no-proof:yes'>__________________________=
_________________</span></font><span
lang=3DEN-GB style=3D'mso-ansi-language:EN-GB;mso-no-proof:yes'> =
</span><span
lang=3DEN-GB style=3D'mso-ansi-language:EN-GB'><o:p></o:p></span></p>

<p class=3DMsoNormal><font size=3D3 face=3D"Times New Roman"><span =
lang=3DEN-GB
style=3D'font-size:12.0pt;mso-ansi-language:EN-GB'><o:p>&nbsp;</o:p></spa=
n></font></p>

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