Categories
JavaScript Technology

Scenario: Internet Zoo

Page and source archived at Wayback Machine. Note, background images were cool in 1997. As for the comment, “The system needs little in the way of security and will reside on a machine totally isolated from any other system”, well, all I can say is those were the days.

The Scenario is a non-profit organization, a mythical city zoo. It represents an online web application that displays static HTML pages and provides for simple queries to a database. No online ordering is occurring, no updates are being made to a database, and no persistent information needs to be maintained between the pages.

This scenario assumes that the organization has not installed a web server. Based on this, this section, and the ones to follow, provide the steps needed to obtain a domain, set up communication protocols, prepare the computer and install and configure the web server.

The system needs little in the way of security and will reside on a machine totally isolated from any other system.

Note that the examples for this approach use Java classes that are not built into the browser, or the standard Sun class library. If you do not have these classes installed on your local machine, they will be downloaded from this server. And this server is not the speediest in the world. What I am trying to say is “Yes. Do take up knitting.”.

Source Code

The source code for the examples in this scenario can be downloaded from this page. Note, though. that the code is not supported by the author, and the author is not responsible for problems that might arise from the download. Now, on that cheerful note (and I am sure you all are breathless with anticipation about the download), grab your source:

Categories
Web

A simple solution to a complex problem

Any information system group that has a client base that is split geographically will have a problem with distribution: how do you notify the clients that a new version of the tool(s) they are using is out, what the version contains, and how to upgrade.

You can automate the upgrade process by using tools that determine that the application a person is accessing is now out of date and upgrading it accordingly. The problem with this approach is that the user will not have control of when the upgrade is occurring and may be wary of an update that they know nothing about.

You can take a more passive approach by sending an email or memo out to all of your clients that an update has occurred to the application and they then can access the update on a certain sub-directory. The problem with this is that unless the update is fixing a problem that the client specifically wants or asked for, they may not be as willing to take the time to make the upgrade to their own installation, and then you in the IS department are now faced with trying to support multiple installations using multiple versions of your product. Additionally, the application user will then have to find this upgrade, download it on their own, and install the upgrade, a multiple step process which can generate problems.

Is there a simple solution? There is a simple possibility.

Many companies are interested in porting applications to the Web in some form of an internal intranet just for this problem. Unfortunately as many IS departments are finding out, most applications will not port to the web that easily. However, this is not the only way the web can be used to solve migration and upgrade problems.

Another approach is to use techniques such as Server Side Includes and to use the concept of the personalized user page. This is a web document that the user will open every morning. The contents of the document have been personalized for the user and presents information from categories that they have chosen. A case in point is that a person who works with Group A in Department 1B for Division J for Company XYZ. They will have a web page that contains new information pertinent to Company XYZ at the top, then information pertinent only to Division J next, information for Department 1B next, and finally information for Group A.

A Server Side Include (SSI) embeds a command line in the HTML document given an extension which is usually .shtml or .stm (the webmaster can determine what this extension is). This type of extension tells the web server to parse the web document for SSI commands before sending the document to the browser. An example of one of these commands is:

<!–#include file=”company.html” –>

This SSI command will instruct the web server to open the file called company.html and load the contents of company.html at this point.

The advantage of this approach should be fairly obvious: the information is specific to the interests and needs of the individual and is presented in such a way that they can examine it for the entire day if they need to; the information can include links to other documents if the person wishes to pursue more in-depth knowledge; and the document can be saved using most browers SaveAs capability. In stead of a flurry of emails which may or may not contain information that is relevant and that can be ignored and difficult to follow or read you have one document that contains all the information.

Another advantage is that no programming is required, and the information for each department can be maintained by each department. Group A maintains the HTML document that is specific to them. If there is no new information a blank HTML document or one containing the words “No New Information” can be given. Division J can maintain their own HTML document, and so on. With the many many simple to use HTML tools this should not be a solution that requires programming intervention.

While presenting a unified approach to information presentation, each group maintains autonomous control over what information is presented.

For our distribution problem, if IS has upgraded software that is in use throughout Division J, a notice can go into the Division J section that a new version of the software is being created, what bugs it will fix and features it will add. When the software is ready, a link can be inserted into the document that will allow the person to download the upgrade with one click of the button. The user can then double click on this file as soon as it is on their machine and the upgrade process can occur.

What is the advantage of this technique over others? The information about the upgrade is presented in the same format and in the same context as the upgrade itself. Information about the upgrade and the upgrade itself are only given to those who are impacted by it.

How can this solve the multiple version problem? After all the user can continue to ignore the upgrade notice and continue on their merry way. Well, this is where the concept of something called a Netscape Cookie comes in.

A Netscape cookie, implemented by both Netscape and Internet Explorer browsers, is a tiny bit of information that is stored locally on the client’s machine and that can be accessed by the browser when a specific web document is loaded. When the document containing the information about the upgrade is loaded, this value is set for the first time. After that point every time the person accesses their personalized web page the cookie is accessed and the value is incremented or decremented. Information can be printed out to the effect that they have so many days to make the upgrade, and this value is decremented for each day.

If they make the upgrade, the cookie information is destroyed and the reader will no longer get the count down.

With additional sophistication, one can create the page in such a way that the download no longer shows once they make the upgrade. To use this approach, persisten information about what HTML documents one specific person will see is kept in a file on the server. When the person logs in and gives their user name and password this file is accessed. Instead of an HTML document the person accesses a file that is called index.cgi. This application will access the file containing the person’s preferences and the information is then used to determine how to build the page the person will see. The application does this by opening up the individual HTML documents that make up the person’s preferences and printing them back to the browser, in turn.

With this approach, after a person makes an upgrade their personal preference file is accessed and the entry that contains the upgrade information is removed. Not only will the person receive timely information that is pertinent to their needs, they will receive content that is dynamic and also matches their choices.

Finally, if the person still does not upgrade by a specific date an email can be generated automatically that will be sent to the IS department informing them of this information.

A link file containing sample Perl script that demonstrates the CGI based approach and that demonstrates the use of SSI can be foundĀ here.