Caching pages leads to a speedier browsing experience and so is a good idea. Replacing information within a web page using Ajax similarly improves the user’s experience. The problem comes when the browser caches the information from the Ajax request. It’s a logical thing to do, but it’s not normally what the developer wants.
There are a number of ways round this. (more…)
In addition to having problems with JNDI not working properly, I’ve also been bashing my head against Plesk–that is supposedly “designed to simplify the management and administration of web sites”.
It’s the interaction between Plesk and Tomcat that’s the particular problem and how both of them negotiate dealing with multiple domains (or rather don’t deal with it). (more…)
If you’re writing a JSP using the JSTL tag <c:catch var=”myError”> … </c:catch> then I’m sure that you know that the next thing to do is to check after the closing catch tag to see if myError is empty. If not you can output some useful error message having successfully caught any exception. However, sometimes it’s useful to actually output the stack trace (when debugging a site for example). It turns out not to be difficult to do this. Simply copy in the following:
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<c:if test="${not empty myError}">
<p class="error">An error occured: <c:out value="${myError}"/></p>
<pre>
<c:forEach var="stackTraceElem" items="${myError.stackTrace}">
<c:out value="${stackTraceElem}"/><br/>
</c:forEach>
One of the problems with using HTML as the user interface is testing it (in fact testing user interfaces has always been a bit of a problem) so I’m always on the look out for good UI testing tools.
For a while I’ve known about and used Watir which scripts Internet Explorer (and now Firefox with FireWatir though it’s a bit more tricky to set up). Watir allows you to write simple but powerful scripts in Ruby that will instruct IE to load up a page, fill in a form, click a button or whatever and then you can make assertions about what should have happened. It’s not difficult to use and even if you don’t know Ruby, if you know other languages, you can soon pick it up.
Today however I came across Selenium (also on the same OpenQA site). This is neat for two reasons: (1) it’s all written in JavaScript so the same script runs in both IE and Firefox, on the PC or Mac; and (2) it has an IDE (a Firefox extension in fact) which lets you record the tests rather than having to write them yourself (you can then save them away and create test suites; you can also load up tests and single step them, etc.). (There is a Watir recorder on the OpenQA site but it’s only version 0.1 so far. There’s also WET which I haven’t tested, but is a Windows application written in Ruby which wraps around Watir.)
The thing I’m currently looking for though is a test environment where I don’t have to install a large infrastructure and which works easily on both PCs and Macs, supporting both IE and Firefox. Selenium seems to give me exactly that. In fact the project’s customer could probably install it on their PC and be able to run the tests (or even record new tests) which would be great.
Please let me know if you know of other tools that would fit the bill or what your experience is with these tools.
