<s>
The	O
Netscape	B-Application
Server	I-Application
Application	I-Application
Programming	I-Application
Interface	I-Application
(	O
NSAPI	O
)	O
is	O
an	O
application	B-Application
programming	I-Application
interface	I-Application
for	O
extending	O
server	O
software	O
,	O
typically	O
web	B-Application
server	I-Application
software	O
.	O
</s>
<s>
NSAPI	O
was	O
initially	O
developed	O
by	O
Rob	O
McCool	O
at	O
Netscape	B-Protocol
for	O
use	O
in	O
Netscape	B-Protocol
Enterprise	O
Server	O
.	O
</s>
<s>
A	O
variant	O
of	O
NSAPI	O
can	O
also	O
be	O
used	O
with	O
Netscape	B-Application
Directory	I-Application
Server	I-Application
.	O
</s>
<s>
As	O
of	O
2007	O
,	O
varying	O
degrees	O
of	O
support	O
for	O
NSAPI	O
are	O
found	O
in	O
Sun	B-Language
Java	I-Language
System	I-Language
Web	I-Language
Server	I-Language
and	O
Zeus	B-Protocol
Web	I-Protocol
Server	I-Protocol
.	O
</s>
<s>
Applications	O
that	O
use	O
NSAPI	O
are	O
referred	O
to	O
as	O
NSAPI	O
plug-ins	B-Application
.	O
</s>
<s>
Each	O
plug-in	B-Application
implements	O
one	O
or	O
more	O
Server	O
Application	O
Functions	O
(	O
SAFs	O
)	O
.	O
</s>
<s>
To	O
use	O
a	O
SAF	O
,	O
an	O
administrator	B-Application
must	O
first	O
configure	O
the	O
server	O
to	O
load	O
the	O
plug-in	B-Application
that	O
implements	O
that	O
SAF	O
.	O
</s>
<s>
This	O
is	O
typically	O
controlled	O
by	O
a	O
configuration	B-Protocol
file	I-Protocol
named	O
magnus.conf	O
.	O
</s>
<s>
Once	O
the	O
plug-in	B-Application
is	O
loaded	O
,	O
the	O
administrator	B-Application
can	O
configure	O
when	O
the	O
server	O
should	O
invoke	O
the	O
SAF	O
and	O
what	O
parameters	O
it	O
should	O
be	O
passed	O
.	O
</s>
<s>
This	O
is	O
typically	O
controlled	O
by	O
a	O
configuration	B-Protocol
file	I-Protocol
named	O
obj.conf	O
.	O
</s>
<s>
NSAPI	O
can	O
be	O
compared	O
to	O
an	O
earlier	O
protocol	O
named	O
Common	B-Language
Gateway	I-Language
Interface	I-Language
(	O
CGI	O
)	O
.	O
</s>
<s>
Like	O
CGI	O
,	O
NSAPI	O
provides	O
a	O
means	O
of	O
interfacing	O
application	B-Application
software	I-Application
with	O
a	O
web	B-Application
server	I-Application
.	O
</s>
<s>
Unlike	O
CGI	O
programs	B-Application
,	O
NSAPI	O
plug-ins	B-Application
run	O
inside	O
the	O
server	O
process	O
.	O
</s>
<s>
Because	O
CGI	O
programs	B-Application
run	O
outside	O
of	O
the	O
server	O
process	O
,	O
CGI	O
programs	B-Application
are	O
generally	O
slower	O
than	O
NSAPI	O
plug-ins	B-Application
.	O
</s>
<s>
However	O
,	O
running	O
outside	O
of	O
the	O
server	O
process	O
can	O
improve	O
server	O
reliability	O
by	O
isolating	O
potentially	O
buggy	B-Error_Name
applications	O
from	O
the	O
server	O
software	O
and	O
from	O
each	O
other	O
.	O
</s>
<s>
In	O
contrast	O
to	O
CGI	O
programs	B-Application
,	O
NSAPI	O
SAFs	O
can	O
be	O
configured	O
to	O
run	O
at	O
different	O
stages	O
of	O
request	O
processing	O
.	O
</s>
<s>
For	O
example	O
,	O
while	O
processing	O
a	O
single	O
HTTP	B-Protocol
request	O
,	O
different	O
NSAPI	O
SAFs	O
can	O
be	O
used	O
to	O
authenticate	O
and	O
authorize	O
the	O
remote	O
user	O
,	O
map	O
the	O
requested	O
URI	B-Protocol
to	O
a	O
local	O
file	O
system	O
path	O
,	O
generate	O
the	O
web	O
page	O
,	O
and	O
log	O
the	O
request	O
.	O
</s>
<s>
After	O
Netscape	B-Protocol
introduced	O
NSAPI	O
,	O
Microsoft	O
developed	O
ISAPI	B-Library
and	O
the	O
Apache	B-Application
Software	O
Foundation	O
developed	O
Apache	B-Application
API	B-Application
(	O
or	O
ASAPI	O
:	O
Apache	B-Application
Server	I-Application
API	B-Application
)	O
.	O
</s>
<s>
All	O
three	O
APIs	B-Application
have	O
a	O
number	O
of	O
similarities	O
.	O
</s>
<s>
For	O
example	O
:	O
NSAPI	O
,	O
ISAPI	B-Library
and	O
Apache	B-Application
API	B-Application
allow	O
applications	O
to	O
run	O
inside	O
the	O
server	O
process	O
.	O
</s>
<s>
For	O
example	O
,	O
Apache	B-Application
API	B-Application
hooks	O
closely	O
resemble	O
those	O
used	O
in	O
NSAPI	O
.	O
</s>
