Sunday, April 27, 2008

Modal Popup Extender, StreamWriter

I've made a small, but useful enhancement to the Waikiki condo rental site I built. The owners of the condo have reservations well in advance so only need to find new people a few times a year. As such, they don't want people constantly writing them, saying such things as, "Hey, can I rent it next week?" This is a waste of time for the writer and for the condo owners.

One way to solve this would be for them to keep me updated about when it was available. But that would mean that I'd have to constantly update the site every few months. Sorry, not interested.

So I built a mechanism whereby they can customize a special message that appears when the user clicks on the Contact page. You can view the current message here:

What you're seeing is an effect provided by the ASP.Net AJAX Control Toolkit. It's called the Modal Popup Extender. It lets you display a Panel (ASP.Net's equivalent of a "Div") that contains whatever controls you want in it. In the example, there are only 3 objects:
  1. The panel, which displays a background image
  2. A label, whose text is customized
  3. An "OK" button
The "disabled" background effect behind the popup panel is caused by the extender referring to this simple CSS entry:

filter:alpha(opacity=70); /* For IE */
opacity:0.7; /* For Firefox */

There's a new Admin page that I added, that is accessed via a link at the bottom of the page, followed by a required password. I could have implemented a full Login mechanism but thought it overkill for this simple application that will forever be used by only 2 people. With that said, I did not embed the password directly in the code for all code files get compiled into a DLL, which is normally accessible by a hacker via the "bin" folder. So instead, I embedded the password in the very secure "web.config" file like this:Arriving on the Admin page, one can only add/edit text and press "Submit" :
Implementing all of this was very simple. For example, the code that writes the text out to a file is this:

if (File.Exists(srcFile))
StreamReader streamReader;
string txt;
streamReader = File.OpenText(srcFile);
txt = streamReader.ReadToEnd();

if (txt != "")
textBox1.Text = txt;

In my local test environment it worked perfectly. But intuitively I knew it wouldn't work right away on my GoDaddy hosted web server. Why? Three words: File write permissions

The text file in question resides in its own folder. This keeps it separate from the code and markup files. What I had to do was go into the GoDaddy File Manager, select this folder, and alter its Permissions so that Write was enabled and not just Read. Without doing that, the file is forever locked from any changes, short of FTP'ing in a new file.

Just some simple techniques here but together they allow for a nice and useful web application!

No comments:

Post a Comment