<s>
Zope	B-Language
is	O
a	O
family	O
of	O
free	B-License
and	I-License
open-source	I-License
web	B-Application
application	I-Application
servers	I-Application
written	O
in	O
Python	B-Language
,	O
and	O
their	O
associated	O
online	O
community	O
.	O
</s>
<s>
Zope	B-Language
stands	O
for	O
"	O
Z	O
Object	O
Publishing	O
Environment	O
"	O
,	O
and	O
was	O
the	O
first	O
system	O
using	O
the	O
now	O
common	O
object	O
publishing	O
methodology	O
for	O
the	O
Web	O
.	O
</s>
<s>
Zope	B-Language
has	O
been	O
called	O
a	O
Python	B-Language
killer	O
app	O
,	O
an	O
application	O
that	O
helped	O
put	O
Python	B-Language
in	O
the	O
spotlight	O
.	O
</s>
<s>
Over	O
the	O
last	O
few	O
years	O
,	O
the	O
Zope	B-Language
community	O
has	O
spawned	O
several	O
additional	O
web	B-Application
frameworks	I-Application
with	O
disparate	O
aims	O
and	O
principles	O
,	O
but	O
sharing	O
philosophy	O
,	O
people	O
,	O
and	O
source	O
code	O
.	O
</s>
<s>
Zope	B-Language
2	O
is	O
still	O
the	O
most	O
widespread	O
of	O
these	O
frameworks	O
,	O
largely	O
thanks	O
to	O
the	O
Plone	B-Language
content	B-Protocol
management	I-Protocol
system	I-Protocol
,	O
which	O
runs	O
on	O
Zope	B-Language
2	O
.	O
</s>
<s>
BlueBream	O
(	O
earlier	O
called	O
Zope	B-Language
3	O
)	O
is	O
less	O
widespread	O
but	O
underlies	O
several	O
large	O
sites	O
,	O
including	O
Launchpad	B-Protocol
.	O
</s>
<s>
Grok	B-Language
was	O
started	O
as	O
a	O
more	O
programmer-friendly	O
framework	O
,	O
"	O
Zope	B-Language
3	O
for	O
cavemen	O
"	O
,	O
and	O
in	O
2009	O
Pyramid	O
gained	O
popularity	O
in	O
the	O
Zope	B-Language
community	O
as	O
a	O
minimalistic	O
framework	O
based	O
on	O
Zope	B-Language
principles	O
.	O
</s>
<s>
The	O
Zope	B-Language
Corporation	O
was	O
formed	O
in	O
1995	O
in	O
Fredericksburg	O
,	O
Virginia	O
under	O
the	O
name	O
Digital	O
Creations	O
,	O
as	O
a	O
joint	O
venture	O
with	O
InfiNet	O
(	O
a	O
joint	O
newspaper	O
chain	O
venture	O
)	O
.	O
</s>
<s>
PythonLabs	O
,	O
creators	O
of	O
Python	B-Language
,	O
became	O
part	O
of	O
the	O
company	O
in	O
2000	O
(	O
Python	B-Language
founder	O
Guido	O
van	O
Rossum	O
left	O
Zope	B-Language
Corp	O
in	O
2003	O
)	O
.	O
</s>
<s>
What	O
is	O
now	O
known	O
as	O
Zope	B-Language
2	O
began	O
with	O
the	O
merging	O
of	O
three	O
separate	O
software	O
products	O
–	O
Bobo	O
,	O
Document	O
Template	O
,	O
and	O
BoboPOS	O
–	O
into	O
the	O
Principia	O
application	B-Application
server	I-Application
.	O
</s>
<s>
At	O
the	O
behest	O
of	O
its	O
largest	O
investor	O
,	O
Opticality	O
Ventures	O
,	O
Principia	O
was	O
re-released	O
as	O
free	B-Application
software	I-Application
under	O
the	O
name	O
Zope	B-Language
in	O
1998	O
.	O
</s>
<s>
Bobo	O
,	O
and	O
therefore	O
Zope	B-Language
,	O
was	O
the	O
first	O
Web	O
object	O
publishing	O
solution	O
.	O
</s>
<s>
In	O
November	O
2004	O
,	O
Zope	B-Language
3	O
was	O
released	O
.	O
</s>
<s>
Zope	B-Language
3	O
is	O
a	O
complete	O
rewrite	O
that	O
preserves	O
only	O
the	O
original	O
ZODB	B-Application
object	O
database	O
.	O
</s>
<s>
Zope	B-Language
3	O
is	O
,	O
however	O
,	O
not	O
compatible	O
with	O
Zope	B-Language
2	O
,	O
so	O
Zope	B-Language
2	O
applications	O
do	O
not	O
run	O
on	O
Zope	B-Language
3	O
.	O
</s>
<s>
It	O
was	O
originally	O
intended	O
to	O
introduce	O
a	O
backwards-compatibility	O
layer	O
so	O
that	O
Zope	B-Language
2	O
software	O
would	O
run	O
on	O
Zope	B-Language
3	O
.	O
</s>
<s>
Instead	O
a	O
module	O
known	O
as	O
Five	O
introduced	O
the	O
new	O
Zope	B-Language
3	O
paradigms	O
into	O
Zope	B-Language
2	O
,	O
although	O
full	O
compatibility	O
is	O
n't	O
possible	O
that	O
way	O
either	O
.	O
</s>
<s>
The	O
existence	O
of	O
two	O
incompatible	O
Web	B-Application
frameworks	I-Application
called	O
Zope	B-Language
has	O
caused	O
a	O
lot	O
of	O
confusion	O
.	O
</s>
<s>
In	O
response	O
,	O
in	O
January	O
2010	O
,	O
Zope	B-Language
3	O
was	O
renamed	O
"	O
BlueBream	O
"	O
.	O
</s>
<s>
"	O
Zope	B-Language
"	O
and	O
"	O
blue	O
bream	O
"	O
are	O
names	O
of	O
a	O
kind	O
of	O
fish	O
,	O
Ballerus	O
ballerus	O
.	O
</s>
<s>
The	O
Zope	B-Language
Foundation	O
is	O
an	O
organization	O
that	O
promotes	O
the	O
development	O
of	O
the	O
Zope	B-Language
platform	O
by	O
supporting	O
the	O
community	O
that	O
develops	O
and	O
maintains	O
the	O
relevant	O
software	B-Architecture
components	I-Architecture
.	O
</s>
<s>
The	O
community	O
includes	O
both	O
open	B-Application
source	I-Application
software	I-Application
,	O
documentation	O
and	O
web	O
infrastructure	O
contributors	O
,	O
as	O
well	O
as	O
business	O
and	O
organization	O
consumers	O
of	O
the	O
software	O
platform	O
.	O
</s>
<s>
It	O
manages	O
the	O
zope.org	B-Language
websites	O
,	O
an	O
infrastructure	O
for	O
open	O
source	O
collaboration	O
.	O
</s>
<s>
A	O
Zope	B-Language
website	O
is	O
usually	O
composed	O
of	O
objects	O
in	O
a	O
Zope	B-Application
Object	I-Application
Database	I-Application
,	O
not	O
files	O
on	O
a	O
file	B-Application
system	I-Application
,	O
as	O
is	O
usual	O
with	O
most	O
web	B-Application
servers	I-Application
.	O
</s>
<s>
This	O
allows	O
users	O
to	O
harness	O
the	O
advantages	O
of	O
object	O
technologies	O
,	O
such	O
as	O
encapsulation	B-Application
.	O
</s>
<s>
Zope	B-Language
maps	O
URLs	O
to	O
objects	O
using	O
the	O
containment	O
hierarchy	O
of	O
such	O
objects	O
;	O
methods	O
are	O
considered	O
to	O
be	O
contained	O
in	O
their	O
objects	O
as	O
well	O
.	O
</s>
<s>
Data	O
can	O
be	O
stored	O
in	O
other	O
databases	O
as	O
well	O
,	O
or	O
on	O
the	O
file	B-Application
system	I-Application
,	O
but	O
ZODB	B-Application
is	O
the	O
most	O
common	O
solution	O
.	O
</s>
<s>
Zope	B-Language
provides	O
two	O
mechanisms	O
for	O
HTML	B-Language
templating	O
:	O
Document	O
Template	O
Markup	O
Language	O
(	O
DTML	O
)	O
and	O
Zope	B-Language
Page	O
Templates	O
(	O
ZPT	O
)	O
.	O
</s>
<s>
However	O
,	O
DTML	O
can	O
be	O
problematic	O
:	O
DTML	O
tags	O
interspersed	O
with	O
HTML	B-Language
form	O
non-valid	O
HTML	B-Language
documents	O
,	O
and	O
its	O
use	O
requires	O
care	O
when	O
including	O
logic	O
into	O
templates	O
,	O
to	O
retain	O
code	O
readability	O
.	O
</s>
<s>
The	O
use	O
of	O
DTML	O
is	O
discouraged	O
by	O
many	O
leading	O
Zope	B-Language
developers	O
.	O
</s>
<s>
ZPT	O
templates	O
can	O
be	O
either	O
well-formed	O
XML	B-Protocol
documents	I-Protocol
or	O
HTML	B-Language
documents	O
,	O
in	O
which	O
all	O
special	O
markup	O
is	O
presented	O
as	O
attributes	O
in	O
the	O
TAL	O
(	O
Template	B-Language
Attribute	I-Language
Language	I-Language
)	O
namespace	O
.	O
</s>
<s>
ZPT	O
offers	O
a	O
very	O
limited	O
set	O
of	O
tools	O
for	O
conditional	O
inclusion	O
and	O
repetition	O
of	O
XML	B-Protocol
elements	O
.	O
</s>
<s>
Consequently	O
,	O
the	O
templates	O
are	O
usually	O
quite	O
simple	O
,	O
with	O
most	O
logic	O
implemented	O
in	O
Python	B-Language
code	I-Language
.	O
</s>
<s>
One	O
significant	O
advantage	O
of	O
ZPT	O
templates	O
is	O
that	O
they	O
can	O
be	O
edited	O
in	O
most	O
graphical	O
HTML	B-Language
editors	O
.	O
</s>
<s>
ZPT	O
also	O
offers	O
direct	O
support	O
for	O
internationalization	B-General_Concept
.	O
</s>
<s>
Zope	B-Language
2	O
underlies	O
the	O
Plone	B-Language
content	B-Protocol
management	I-Protocol
system	I-Protocol
,	O
as	O
well	O
as	O
the	O
ERP5	B-Application
open	O
source	O
enterprise	O
resource	O
planning	O
system	O
.	O
</s>
<s>
BlueBream	O
is	O
a	O
rewrite	O
by	O
the	O
Zope	B-Language
developers	O
of	O
the	O
Zope	B-Language
2	O
web	B-Application
application	I-Application
server	I-Application
.	O
</s>
<s>
It	O
was	O
created	O
under	O
the	O
name	O
"	O
Zope	B-Language
3	O
"	O
,	O
but	O
the	O
existence	O
of	O
two	O
incompatible	O
frameworks	O
with	O
the	O
same	O
name	O
caused	O
much	O
confusion	O
,	O
and	O
Zope	B-Language
3	O
was	O
renamed	O
"	O
BlueBream	O
"	O
in	O
January	O
2010	O
.	O
</s>
<s>
BlueBream	O
is	O
distributed	O
under	O
the	O
terms	O
of	O
the	O
Zope	B-Language
Public	I-Language
License	I-Language
and	O
is	O
thus	O
free	B-Application
software	I-Application
.	O
</s>
<s>
Zope	B-Language
2	O
has	O
proven	O
itself	O
as	O
a	O
useful	O
framework	O
for	O
Web	O
applications	O
development	O
,	O
but	O
its	O
use	O
revealed	O
some	O
shortcomings	O
.	O
</s>
<s>
To	O
name	O
a	O
few	O
,	O
creating	O
Zope	B-Language
2	O
products	O
involves	O
copying	O
a	O
lot	O
of	O
boilerplate	O
code	O
–	O
"	O
magic	O
"	O
code	O
–	O
that	O
just	O
has	O
to	O
be	O
there	O
,	O
and	O
the	O
built-in	O
management	O
interface	O
is	O
difficult	O
to	O
modify	O
or	O
replace	O
.	O
</s>
<s>
Zope	B-Language
3	O
was	O
a	O
rewrite	O
of	O
the	O
software	O
that	O
attempts	O
to	O
address	O
these	O
shortcomings	O
while	O
retaining	O
the	O
advantages	O
of	O
Zope	B-Language
that	O
led	O
to	O
its	O
popularity	O
.	O
</s>
<s>
BlueBream	O
is	O
based	O
on	O
a	O
component	B-Architecture
architecture	I-Architecture
that	O
makes	O
it	O
easy	O
to	O
mix	O
software	B-Architecture
components	I-Architecture
of	O
various	O
origins	O
written	O
in	O
Python	B-Language
.	O
</s>
<s>
Although	O
originally	O
intended	O
as	O
a	O
replacement	O
for	O
Zope	B-Language
2	O
,	O
the	O
Zope	B-Language
Component	B-Architecture
Architecture	I-Architecture
has	O
instead	O
been	O
backported	O
to	O
Zope	B-Language
2	O
,	O
starting	O
with	O
Zope	B-Language
2.8	O
.	O
</s>
<s>
Many	O
Zope	B-Language
platforms	O
such	O
as	O
Plone	B-Language
are	O
going	O
through	O
the	O
same	O
type	O
of	O
piece-by-piece	O
rewriting	O
.	O
</s>
<s>
The	O
first	O
production	O
release	O
of	O
the	O
new	O
software	O
,	O
Zope	B-Language
X3	O
3.0.0	O
,	O
was	O
released	O
on	O
November	O
6	O
,	O
2004	O
.	O
</s>
<s>
The	O
Zope	B-Language
3	O
project	O
started	O
in	O
February	O
2001	O
as	O
an	O
effort	O
to	O
develop	O
a	O
new	O
version	O
of	O
Zope	B-Language
as	O
an	O
almost	O
complete	O
rewrite	O
,	O
with	O
the	O
goal	O
to	O
retain	O
the	O
successful	O
features	O
of	O
Zope	B-Language
2	O
while	O
trying	O
to	O
fix	O
some	O
of	O
its	O
shortcomings	O
.	O
</s>
<s>
The	O
goal	O
was	O
to	O
create	O
a	O
more	O
developer-friendly	O
and	O
flexible	O
platform	O
for	O
programming	O
web	O
applications	O
than	O
Zope	B-Language
2	O
is	O
.	O
</s>
<s>
The	O
project	O
began	O
with	O
the	O
development	O
of	O
a	O
component	B-Architecture
architecture	I-Architecture
,	O
which	O
allows	O
the	O
structuring	O
of	O
code	O
into	O
small	O
,	O
composable	O
units	O
with	O
introspectable	O
interfaces	O
.	O
</s>
<s>
The	O
interfaces	O
are	O
supported	O
by	O
an	O
interface	O
package	O
in	O
order	O
to	O
provide	O
the	O
functionality	O
of	O
explicitly	O
declared	O
interfaces	O
to	O
the	O
Python	B-Language
language	I-Language
.	O
</s>
<s>
The	O
first	O
production	O
release	O
of	O
the	O
software	O
,	O
Zope	B-Language
X3	O
,	O
was	O
released	O
on	O
November	O
6	O
,	O
2004	O
.	O
</s>
<s>
In	O
January	O
2010	O
Zope	B-Language
3	O
was	O
renamed	O
BlueBream	O
.	O
</s>
<s>
The	O
goal	O
of	O
the	O
project	O
was	O
to	O
enable	O
programmers	O
to	O
use	O
Zope	B-Language
in	O
order	O
to	O
expose	O
arbitrary	O
Python	B-Language
objects	O
as	O
model	O
objects	O
to	O
the	O
web	O
without	O
the	O
need	O
to	O
make	O
these	O
objects	O
fulfill	O
particular	O
behavior	O
requirements	O
.	O
</s>
<s>
In	O
Zope	B-Language
2	O
there	O
had	O
been	O
many	O
behavior	O
requirements	O
to	O
allow	O
objects	O
to	O
participate	O
in	O
the	O
framework	O
,	O
which	O
resulted	O
in	O
a	O
large	O
amount	O
of	O
mixin	B-Language
base	O
classes	O
and	O
special	O
attributes	O
.	O
</s>
<s>
Views	O
and	O
models	O
are	O
linked	O
together	O
by	O
the	O
component	B-Architecture
architecture	I-Architecture
.	O
</s>
<s>
The	O
libraries	O
underlying	O
BlueBream	O
have	O
been	O
evolving	O
into	O
a	O
collection	O
of	O
useful	O
libraries	O
for	O
web	O
application	O
development	O
rather	O
than	O
a	O
single	O
,	O
monolithic	O
application	B-Application
server	I-Application
.	O
</s>
<s>
BlueBream	O
includes	O
separate	O
packages	O
for	O
interfaces	O
,	O
component	B-Architecture
architecture	I-Architecture
,	O
HTTP	B-Application
server	I-Application
,	O
publisher	O
,	O
Zope	B-Application
Object	I-Application
Database	I-Application
(	O
ZODB	B-Application
)	O
,	O
Zope	B-Language
Page	O
Templates	O
,	O
I18N	B-General_Concept
,	O
security	O
policy	O
,	O
and	O
so	O
on	O
.	O
</s>
<s>
The	O
component	B-Architecture
architecture	I-Architecture
is	O
used	O
to	O
glue	O
these	O
together	O
.	O
</s>
<s>
The	O
component	B-Architecture
architecture	I-Architecture
is	O
configured	O
using	O
a	O
ZCML	O
(	O
Zope	B-Language
Configuration	O
Markup	O
Language	O
)	O
,	O
an	O
XML	B-Protocol
based	O
configuration	O
file	O
language	O
.	O
</s>
<s>
The	O
Zope	B-Language
3	O
project	O
pioneered	O
the	O
practice	O
of	O
sprints	O
for	O
open	B-Application
source	I-Application
software	I-Application
development	O
.	O
</s>
<s>
BlueBream	O
is	O
considered	O
a	O
stable	O
framework	O
,	O
used	O
on	O
production	O
projects	O
worldwide	O
,	O
most	O
notably	O
Launchpad	B-Protocol
.	O
</s>
<s>
As	O
a	O
result	O
of	O
the	O
development	O
of	O
Zope	B-Language
3	O
/	O
BlueBream	O
,	O
there	O
are	O
now	O
many	O
independent	O
Python	B-Language
packages	O
used	O
and	O
developed	O
as	O
a	O
part	O
of	O
BlueBream	O
,	O
and	O
although	O
many	O
of	O
these	O
are	O
usable	O
outside	O
of	O
BlueBream	O
,	O
many	O
are	O
not	O
.	O
</s>
<s>
The	O
Zope	B-Language
Toolkit	O
(	O
ZTK	O
)	O
project	O
was	O
started	O
to	O
clarify	O
which	O
packages	O
were	O
usable	O
outside	O
BlueBream	O
,	O
and	O
to	O
improve	O
the	O
re-usability	O
of	O
the	O
packages	O
.	O
</s>
<s>
Thus	O
the	O
Zope	B-Language
Toolkit	O
is	O
a	O
base	O
for	O
the	O
Zope	B-Language
frameworks	O
.	O
</s>
<s>
Zope	B-Language
2.12	O
is	O
the	O
first	O
release	O
of	O
a	O
web	B-Application
framework	I-Application
that	O
builds	O
on	O
Zope	B-Language
Toolkit	O
,	O
and	O
Grok	B-Language
and	O
BlueBream	O
were	O
set	O
to	O
have	O
releases	O
based	O
on	O
the	O
ZTK	O
during	O
2010	O
.	O
</s>
<s>
In	O
2006	O
the	O
Grok	B-Language
project	O
was	O
started	O
by	O
a	O
number	O
of	O
Zope	B-Language
3	O
developers	O
who	O
wanted	O
to	O
make	O
Zope	B-Language
3	O
technology	O
more	O
agile	O
in	O
use	O
and	O
more	O
accessible	O
to	O
newcomers	O
.	O
</s>
<s>
Grok	B-Language
has	O
since	O
then	O
seen	O
regular	O
releases	O
and	O
its	O
core	O
technology	O
(	O
Martian	O
,	O
grokcore.component	O
)	O
is	O
also	O
finding	O
uptake	O
in	O
other	O
Zope	B-Language
3	O
and	O
Zope	B-Language
2	O
based	O
projects	O
.	O
</s>
<s>
In	O
late	O
2017	O
,	O
development	O
began	O
on	O
Zope	B-Language
4	O
.	O
</s>
<s>
Zope	B-Language
4	O
is	O
a	O
successor	O
to	O
Zope	B-Language
2.13	O
,	O
making	O
many	O
changes	O
that	O
are	O
not	O
backwards	O
compatible	O
with	O
Zope	B-Language
2	O
.	O
</s>
<s>
Zope	B-Language
5	O
was	O
released	O
in	O
2020	O
.	O
</s>
<s>
As	O
mentioned	O
previously	O
,	O
Zope	B-Language
page	O
templates	O
are	O
themselves	O
XHTML	O
documents	O
,	O
which	O
means	O
they	O
can	O
be	O
viewed	O
and	O
edited	O
using	O
normal	O
HTML	B-Language
editors	O
or	O
XHTML	O
compliant	O
tools	O
(	O
a	O
big	O
advantage	O
compared	O
to	O
other	O
template	O
languages	O
used	O
for	O
Web	O
applications	O
)	O
.	O
</s>
<s>
Instead	O
they	O
are	O
marked	O
up	O
with	O
additional	O
elements	O
and	O
attributes	O
in	O
special	O
XML	B-Protocol
namespaces	O
(	O
see	O
below	O
)	O
.	O
</s>
<s>
You	O
can	O
use	O
Python	B-Language
to	O
alter	O
the	O
href	O
at	O
runtime	O
.	O
</s>
<s>
This	O
is	O
a	O
very	O
cursory	O
explanation	O
of	O
Zope	B-Language
Page	O
Templates	O
.	O
</s>
<s>
The	O
behavior	O
of	O
Zope	B-Language
Page	O
Templates	O
is	O
almost	O
completely	O
described	O
by	O
a	O
template	O
language	O
,	O
fixed	O
on	O
TAL	O
,	O
TALES	B-Language
,	O
and	O
METAL	O
specifications	O
:	O
</s>
<s>
Template	B-Language
Attribute	I-Language
Language	I-Language
(	O
TAL	O
)	O
,	O
</s>
<s>
Template	B-Language
Attribute	I-Language
Language	I-Language
Expression	I-Language
Syntax	I-Language
(	O
TALES	B-Language
)	O
,	O
</s>
<s>
Macro	O
Expansion	O
Template	B-Language
Attribute	I-Language
Language	I-Language
(	O
METAL	O
)	O
.	O
</s>
<s>
SchoolTool	B-Application
is	O
an	O
open	O
source	O
student	B-Application
information	I-Application
system	I-Application
that	O
uses	O
Zope	B-Language
.	O
</s>
<s>
Plone	B-Language
is	O
an	O
open	O
source	O
content	B-Protocol
management	I-Protocol
system	I-Protocol
that	O
uses	O
Zope	B-Language
.	O
</s>
