[ZDP] History Second review

[Tom Deprez]

Second revision: ASP and PHP.!
---------------------------------------------

 Ok, moving again on slick ice, i've added a part of PHP in the historie of
 the web... I don't know anything about it, so I guess it can be pretty
 rubbish. Hope someone on the list is familiar with it and can make
 corrections, additions to it...

 <SNIP>There is another problem with the scripts solution for a dynamic web.
 Each script may do the same thing (respond to  users, fetch data, and
 generate a web page) in a slightly different way. Each different way makes
 a new, different bug,  inconsistency or security hole possible. Although
 within limits it is nice that people can solve the same problems in
 different ways (as each way has its own advantages and disadvantages), if
 every script has to re-invent the wheel all over, it is far more work to
 write them and debug them, and to make them work together. It also becomes
 a problem  later, when they need to be maintained.
 </SNIP>

 <NEW>
So, people tried to find other solutions to these common problems. One of
these approaches is the use
of a CGI wrapper,  with an appropriat scripting language. Based on embedding
special tags in the HTML file right away
which the CGI-wrapper in his turn parsed. The special tags are recognised
and depending on these tags,  commands can be excecuted at server side. For
instance, an embedded SQL query is used to query a database and the
results or embedded in the result HTML file sended back to the user. Such
utilities are called HTML-embedded scripting languages. This approach
results in the use of mostly one CGI script which is used to parse the
incomming HTML file. And because it was only one CGI script, it can be
integrated in the web sever itself, eliminating the need to start up a
seperate CGI program to generate a web page. However,  HTML, SQL queries,
the scripting language, etc all reside in the HTML file, reducing its
readability. It not only reduces the readability but it makes it also very
hard for different programmers working on the web site. Getting connection
to several databases, etc are still a relative difficult
task. And although we don't need several CGI-scripts, there are still pretty
much HTML-files to manage, which all can have haevy scripting-languages
inside them. An example of such a scripting language is PHP, written by
Rasmus Lerdorf, and it is pretty popular.

Another of these approaches is using a web server with build in objects and
a scripting language. This totally removes the use of a CGI-script but on
the other hand, you're depended on the web server itself. Other web servers
don't understand the scripting language in the HTLM file. Like the previous
approach, HTML and scripting language are mixed which each other. As example
you can look at the .ASP files of the IIS Server.

So, although these approaches reduce some of the problems, they are still
not perfect.
</NEW>

<SNIP>
There is a trend in the development of the web. At first, web sites mainly
published static pages. This can be  compared to what magazines do. But
we're dealing with the Internet here, not magazines. Interactivity and
communication are the main things that make the net so powerful and
appealing. After all, computers can do more  than glossy paper! Computers
run *applications*, not magazines. So it is natural that people expect that
web sites to  be more like applications. A dynamic web sites behaves like
an application; both on the end user side (where users interact with the
site), and on the side of the people who provide the contents for the site
-- and with the Internet often there's an overlap between these two parties.
</SNIP>

Tom.

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