Comment by pavement | Hacker News Reader

Comment by pavement | Hacker News Reader

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This practice has nothing to do with Java, at all. It is not an approach that was invented by Java, for Java, and it is not in any way unique to Java.

Most web technologies support rendering a view based on a set of values residing in a database, and use the values to populate a template. The template contains placeholders reserved for values expected to originate from a database.

The version of the page that appears in your web browser usually does not exist as a serialized HTML page on a disk connected to a server. It often only exists as a representation of two pieces of information bound to a session in memory on a server: 1. The Template or server-side script, 2. the values you are authorized to retrieve from the database, which may or may not be a SQL database.

What you see in the address bar does not need to correlate to the HTML rendered in the browser window. JavaScript (which is not Java) often employs this technique, termed as a "single page web application."

This is true for PHP, Mcrosoft, Ruby, Python, Perl, server-side JavaScript (such as node.js) and yes Java too.

What's being described above isn't simply template-based rendering (which, yes, essentially everything does), but the practice of building web-software like desktop software and keeping the state of the UI server-side. It ignores that browsers are capable of effectively forking the UI through (today) tabs and (historically) "Open in New Window". Interacting with such software is a profoundly unpleasant experience; thankfully it's not particularly common, especially outside of "enterprise" applications (including government services, public utilities, education management, property management, healthcare, etc.)

It is not Java-specific, but it is common to a few specific Java frameworks as well as at least one of Microsoft's older frameworks (I forget which one).

The vast majority of frameworks (including most modern Java frameworks) do the sane thing and keep application state on the server side (often in a database, as you describe) and UI state on the browser side, which allows links and forms to work the way links are generally supposed to work.

> It is not Java-specific, but it is common to a few specific Java frameworks as well as at least one of Microsoft's older frameworks (I forget which one).

ASP.NET WebForms has a feature where the Session ID, normally stored in a cookie, is stored in the request URL path instead. This was done back in 1999-2001 to support extremely rudimentary HTTP clients which did not support HTTP Cookies - imagine really prototypical mobile-phone web-browsers or hastily-written shell scripts using CURL.

Fortunately it was disabled by default and the documentation describes why it's a bad idea to use it - and I understand the business reasons for including it - however this design does not break things like multiple-tab browsing: that's just what happens when you have any stateful web-application, regardless of framework.

It's now gone in ASP.NET MVC (where you gave full control over rendered URLs), so that horrid chapter has ended.

Which is great, because everybody should downvote anything because of a mild distinction, rather than the wildly off the mark question that prompted a reasonable response. Good job!

I, at least, did not downvote the original post. I assumed it was honest ignorance of the practice I described in my reply.

  What's being described above isn't simply template-based rendering

How are you able to draw that conclusion?

The GP didn't supply a link as an example. It is simply a non-specific anecdotal remark, with no further evidence provided.

Well, the post I responded to included a more or less textbook description of template based rendering. It's a response to a response to this:

> The bizarre practice of assigning session keys to visitors and somehow storing the page they're viewing in the server instead of in the URL is pretty common in Brazilian government, which is dominated by Java programmers.

Having dealt with such a service just today (King County Recorder's Office public records search) that behaves in this manner, I felt pretty familiar with what I was describing.

It is entirely possible I'd misapprehended the situation, but as it's an informal conversation on the internet about bad web development practices, I'm going going to dwell on it too much.

You got what I meant correctly. Thank you for understanding me.

I don't know how could anyone think I was talking about general template rendering (but maybe I expressed myself badly, English is not my first language).

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