Washington Apple Pi

A Community of Apple iPad, iPhone and Mac Users


VSE Link Tester

by David L. Harris

Washington Apple Pi Journal, reprint information

In the January/February 1997 Journal, in an article titled "WebArranger Update," I mentioned that I used a shareware application called Big Brother to check the URLs of the list of user groups that I maintain on the Pi's Web site. Unfortunately, the Macintosh version of Big Brother is no longer supported by its author, François Pottier. I never found Big Brother to be completely stable, but more importantly, in recent times it produces more false negatives (says a URL is bad when it is OK) and false positives (says a URL is good when it is not) than it did in the past. Why this is so I am not sure; perhaps the error messages sent back by Web servers have changed over time, and Big Brother has not kept up with the changes. In any case, when I was offered a chance to review VSE Link Tester, which does a similar job, I took the opportunity. Since the user group pages now have more than a thousand links, I cannot visit them all each month to update the list. (I do try to visit about half each month, a job which has become much easier since I got high-speed Internet access.) In addition, I have the User Group Specials page <http://www.wap.org/specials/default.html> to check, so an automated tester is very welcome. Anyone with a Web site having many links (URLs) , both internal and external, is well advised to take advantage of some sort of automated link checker to keep it up to date.

 Standard or Business?

VSE Link Tester is available in two different versions: VSE Link Tester Standard and VSE Link Tester Business. The $34.95 Standard version allows testing one Web site at a time. It's for private home pages and smaller business sites. The $99.95 Business version is for Webmasters that deal with many Web sites or large corporate sites. I received the Business edition, version 3.2.1.

main window

Figure 1: Link Tester Main Window

 Setting it up

Figure 1 shows the Link Tester main window, with notes added indicating what the buttons do. Several Web pages are listed in the window; if this were the Standard version, only one could be listed. However, with that version, if you want to test another document, you only need to click the "Edit Link" button (the little icon 4th from the left at the bottom) and change to the document that you want to check. (As you move the cursor over each button, a box comes up showing what its function is&endash;a handy feature.) Both local (on my hard drive) and remote (on the Internet) documents are represented in Figure 1. One of the documents is highlighted, ready for link testing, or indeed, to apply the buttons to it.

edit links

Figure 2: Edit Links

When you add a document, whose URLs you want to check, to Link Tester, you are taken automatically to the General panel of the Edit Link window (Figure 2). There you see several options that can be turned on or off, so you can more finely tune which links you want tested. The Remote Links tab takes you to Figure 3, where you can tell Link Tester to ignore remote links, or define several parameters for testing links in real time. From the Local Links tab you can tell Tester to ignore local links, check for upper/lower case in local links, and access other options for mapping local links within folders on your hard drive. Filter allows you to define links (e.g. those containing "cgi-bin") that should not be tested, and the Advanced panel gives the option of including required passwords, and of specifying the browser that Link Tester should emulate, among a list that Link Tester knows. It does not include OmniWeb for OS X. The feature is useful for Webmasters who create different pages for different browsers. Each file listed in Link Tester's main window can have its own set of all these options.

remote links

Figure 3: Remote Links

Figure 4 shows the General panel of Preferences. You can specify which text editor with which to edit links, among other options. The Link Test panel lets you specify a proxy server if your ISP uses one, and to tell whether to test links with <FORM ACTION> tags. In the Report panel you can specify if an HTML report is to be created, in which browser it will open, the text editor for the report, and if broken links only should be reported.


Figure 4: Setting Preferences

 Link Tester in action

Figure 5 shows Link Tester with an almost completed (98.5%) test. The upper scrolling window shows URLs currently being tested; the middle window shows verified links, and the bottom scrolling window shows links that Link Tester reports as broken. (In the Remote Links panel you can choose how many links are tested concurrently.) While Link Tester is checking remote links online, you can double-click on a URL in any of the windows to go to that location in your chosen Web browser. However, only the last three verified links show in the middle window; it is not scrollable. So if a link has been verified some time ago it will not show in the window. The Error Explanation... button gives you more information on the nature of the error message received by Link Tester for a selected link in the bottom window. When it is done with a test, Link Tester creates a report in HTML format; Show Report opens that report in your chosen browser when the test is complete.

link tester in action

Figure 5: Link Tester in Action

 The report

Figure 6 shows a Link Tester report, seen in Netscape Communicator. The top part is a list of links both good and bad, while further down in the report is a more detailed list of broken links. Clicking on any of the links in the browser will, of course, take you, or attempt to take you, to that location on the Web, assuming you are connected to the Internet. Note from the two parts of the report that only broken links show more than the plain URL. This can be an annoyance if you want to double-check links reported as good (by attempting a connection with your browser): you cannot easily see what item in the tested document is referred to by the bare URL. By contrast, a broken link may be "Green Apple User Group," which I find is much more easily recognized.

link tester report

Figure 6: Link Tester Report

 Reports compared

By contrast, Figure 7 shows a short completed test using Big Brother. Each item is identified both by the name of the link as a user would see it on the Web page (on the left) and its URL (right). Whether the link was found OK or not is indicated under Diagnostic, with broken links in red. One does not have to go to a browser to see the report. Selecting any item and typing Command-K opens that link in your browser.

big brother in action

Figure 7: Big Brother in Action

 How good is it?

As mentioned above, I have found that Big Brother is increasingly inaccurate in reporting whether links are good or not. How does VSE Link Tester compare in doing the basic job it is designed to do? In short, it seems to be much better&endash;not perfect, but better. Like Big Brother it sometimes reports any connecting link as OK. This one was found to be a good link: <http://www.ision.nl/not_found.html>. Going to this page with a browser quickly indicates that it is an error report page. This illustrates why it is sometimes good to manually check links that a tester OK's. Link Tester also sometimes reports that a link is broken, and a subsequent check with a browser connects without problems. However, it is possible that the link was bad when Link Tester was looking, but later returned to Internet view&endash;it happens.

A small puzzle unsolved

Figure 8 illustrates the bottom part of a test report on a file that contained 33 links. Link Tester reported that 31 links were good and two failed. However, it only showed one that was broken. Which one of the 33 did it report as broken but does not show? Because it only reports bare URLs for links that test OK, I did not have the patience to cross-check every URL with the original file to see which one it had left out. If all the good links had been identified with their text names I probably could have caught the missing one much more easily.

link tester puzzle

Figure 8: A Puzzle


VSE Link Tester 3.2.1 requires a Macintosh with a PowerPC processor, System 7.1 or higher (7.6.1 or higher recommended), and 8 MB free RAM. It comes with documentation in HTML format; just open it in your Web browser. The Tester is easy to learn to use, and for the most part it works well. It greatly simplifies the life of anyone who wants to keep Web pages up to date. I found some shortcomings in its report format. You often must wait until Link Tester is finished in order to manually check many links, using the report, and it only shows "good" links as bare URLs. Nevertheless it does its basic job well.

VSE Link Tester: