You're an evil man sending a Word document Josh considering
the Check This virus we've seen... :) But I like the intent
of your sig, godspeed the day.
I'll read it if you reformat it into something sensible. Heck, throw
up an HTML site on Geocities if need be and post a URL.
Also:
> 4th- Security is always invoked by the servlet. JSP pages would
be blocked
> by the web server from direct invocation to insure that all JSP pages have
> security. Security might need to be reinvoked at the Application server
> level as well for redundancy (in case the request is from a non-http
> source).
How do you go about blocking direct invocation of these JSP's? (I guess I
should
ask first what web server you're using at it will be dependant on this, no?)
Regards,
Joe.
----- Original Message -----
From: "Joshua Lannin" <[EMAIL PROTECTED]>
To: <[EMAIL PROTECTED]>
Sent: Thursday, January 06, 2000 7:58 AM
Subject: Architecture- Use of Servlets
> Recently I have been helping my company develop a model for a
two-tier
> architecture which will be easily migrated to an EJB multi-tier
environment.
> We have created the attached document which details the architecture we
are
> going to be working with. I'd like to solicit comments from this mailing
> list, as well as make it available to others. It is loosely based on some
> various MVC design pattern articles.
>
> In this scenario (see the doc), the http request comes into the
servlet,
> which is the controller. The controller checks security (this eliminates
> having security dependant on calling a bean directly from the jsp). The
> controller then does any site setup, and calls a 'header' document.
>
> Next, the 'data frame' JSP is invoked. This JSP is called by
either having
> the previous JSP post a name value pair (template='test.jsp'), or by
> invoking a workflow component. The JSP will call a bean to get it's
> content. The bean itself does not do any JDBC or other types of lookups,
it
> will call a class file which will do any low level queries. The class
file
> might return a vector of results to the bean, which will then format the
> results into html, and pass this to the JSP.
>
> This way if we have resources which need to be retrieved by
non-html
> queries, we have a set of classes which we can use, while the beans are
> really there to turn data into html which is then encapsulated in the
> calling JSP page. Also these class files can eventually be turned into
> EJBs, easing migration.
>
> So once the 'data frame' jsp is complete, the servlet then calls a
footer
> document, and results are returned to the browser.
>
> There are a number of rules to the system.
>
> 1st- the servlet acts as a 'dumb' controller. It does not
'generate' new
> html, but rather calls JSP pages (or other servlets) to create new html.
>
> 2nd- navigation logic resides in the JSP. Now I know this goes
against
> many of the articles I have seen of late which suggest that all navigation
> be determined in the servlet, by say, basing decisions on the user session
> or form information. I personally find this to be a very cumbersome
system,
> and prefer to leave any decision making to the JSP page. Some of our JSP
> pages are extremely complex, and have different presentation anyway
> depending on the context in which they are called (for example forms which
> are pre-populated or not depending on if they are editing or creating a
> record). Also this fits more in line with other tag-markup languages such
> as Cold Fusion.
>
> 3rd- beans format information into HTML, which is configurable
based on
> which bean parameters are invoked. Beans never do low level queries,
these
> are left to class files (typically running in another JVM)
>
> 4th- Security is always invoked by the servlet. JSP pages would
be blocked
> by the web server from direct invocation to insure that all JSP pages have
> security. Security might need to be reinvoked at the Application server
> level as well for redundancy (in case the request is from a non-http
> source).
>
>
> I know this is a reasonably long email but I'd like to get some
reaction
> from anyone who has the time to read all this! I am especially interested
> in the ability of pages created in this architecture (which is really
> two-tier) to be migrated to and EJB multi-tier architecture.
>
> Josh Lannin
>
> ------------------------------------------
> Soon we'll be saying 'Back in my
> millennium we still used Microsoft...'
>
> _|_|_| _|_|_| _|_|_|
> _| _| _|
> _| _|_| _| _|_|
> _| _| _| _|
> _|_|_|lobal _|_|_|ommerce _|_|_|ystems
>
> Joshua D. Lannin 4840 Pearl East Circle
> Software Engineer Suite 301-W
> [EMAIL PROTECTED] Boulder, CO, 80301
> ------------------------------------------
>
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