Technology Tales

Perl vs. PHP: A Personal Experience

Ever since I converted it from a client-side JavaScript-powered affair, my online photo gallery has been written in Perl. There have been some challenges along the way, figuring out how to use hash tables has been one, but everything has worked as expected. However, I am now wondering if it is better to write things in PHP for the sake of consistency with the rest of the website. I had a go a rewriting the random photo page and, unless I have been missing something in the Perl world, things do seem more succinct with PHP. For instance, actions that formerly involved several lines of code can now be achieved in one. Reading the contents of a file into an array and stripping HTML/XML tags from a string fall into this category, and seeing the number of lines of code halving is a striking observation. I am not going to completely abandon Perl, it's a very nice language, but I do rather suspect that there is now an increased chance of my having a website whose server-side processing needs are served entirely by PHP.

A peculiarity with PROC EXPORT

I have just encountered an issue with PROC EXPORT that I did not expect to see: it needs to run in a windowing environment. The way that I found this was that I was running a SAS macro as part of a batch job in a headless UNIX session and my program stopped dead with the job needing to be killed; that returned a message containing something about SAS/FSP and SAS/AF which does explain things. Still, this was not something that I would have expected with an export to a CSV file; the behaviour sounds more what you see with the likes of PROC GPLOT or PROC REPORT. As it happened, adding the -noterminal option to the batch command line sorted things out.

Getting one’s HTTP headers in a twist

I am in the process of further linking the content of hillwalking blog into the fabric of other parts of my website. To date, this has included adding a list of all the posts to the site map and a dossier of the latest entries to the site's welcome page. One thing that started to crop up were a series of warnings of the form:

Cannot modify header information - headers already sent by...

The cause of this was my calling a PHP script that was part of my hillwalking blog installation, and this caused Bad Behaviour to be invoked. The result was that an HTTP header was being sent to create a cookie after one already had been sent to display a web page. A spot of conditional coding and the use of an extra flag resolved the problem.

Apparently, there is another surefire way of getting the same result: whitespace before or after the <?php ... ?> tag in an included script. The cookie issue is one that I can understand, but it does seem strange that an attempt is made to send HTTP header information when the latter arises. It causes loads of questions, though...

Restrictions on SAS libraries when macro catalogs are used

When you open up a SAS macro catalogue so that its entries for use by other programs, it has a major impact on the ability to change the library reference used to access the catalogue after it has apparently been unlocked.

options mstored sasmstore=bld_v001;

Using the line above will open the catalogue for reading, but there is no way to close it to change the library reference or unassign it until the SAS session is shut down. Even this line will not do the trick:

options nomstored sasmstore='';

What it means in practice is that if you have a standard macro setting up access to a number of standard macro libraries, then that setup macro needs to check for any library references used and not try to reassign them, causing errors in the process.

Exploring AJAX

SQL Developer Java error

Last night, I tried starting up Oracle's SQL Developer so that I could add a listing of my hillwalking blog posts to my website's site map with a spot of PHP scripting. However, all that I got was something like that which you see below:

I must confess that this one threw me. The solution, though challenging to find (they often are, even with the abilities of Google) was to use a batch file called sqldeveloper.bat that you can find in the [installation directory]\sqldeveloper\bin directory. It does start the thing when all else seems to fail and got me up and running again. I did get that blog post listing added to the site map after all; Having more visibility of the MySQL tables was a definite plus point.

Windows Sysinternals

In an earlier post, I wondered about command line management of Windows processes. Well, I have since located the sort of tools that I was after as part of the Windows Sysinternals toolkit. It began as an independent endeavour and continued as such until Microsoft acquired them in 2006. You can find out more about the process utilities here, and the whole Sysinternals suite can be downloaded in a single package.

Using alternative editors for SAS programming

When it comes to writing SAS programs, most use the tools that SAS gives us, be it Enterprise Guide, the Enhanced Editor or the Program Editor. While Enterprise Guide can work with UNIX SAS as the processing engine, it is very much a Windows tool and the Enhanced Editor functionality is provided through Windows-only programming (ActiveX, I seem to recall). However, that means that creature comforts are left behind you if you turn to writing SAS code using UNIX SAS; you have only got the good old-fashioned Program Editor supplied by SAS itself. However, there is a trick that you can use to make life more comfortable: SAS does allow you to submit the contents of your paste buffer (or clipboard) using the command SUBMIT BUFFER=DEFAULT and this can be assigned to a function key for ease of use (I use the same key to clear the log and output screens at the same time). In the Windows, you may need to explicitly copy the code to do this but, in UNIX, merely highlighting a section of code with an editor like NEdit will do the trick and, given that NEdit is reasonably pleasant tool for code cutting (the ability to define its macros with a spot of scripting is a definite plus point), this makes life more comfortable again.

Selecting SAS code in the Program Editor on UNIX

Here's a possible bugbear with programming using the SAS Display Manager in UNIX, selecting sections of code and running them. In the installations that I have encountered, the mouse selection is not retained, so the code selection cannot be run. There is a fix for this that is not the most obvious. Going to the Preferences dialogue box (Tools > Options > Preferences... from the menu bar) and selecting the Editing tab brings up the screen below:

Ensuring that "Automatically store selection" is switched off, as shown above, will allow one to select and submit sections of code from a SAS program like what is normal practice with Windows SAS. Though it isn't an obvious solution, it does the trick for me.

Photo gallery trouble

The recent woes at Zooomr (mustn't forget that it is spelt with three O's...), have prompted me to ponder photo galleries. My own is a self-hosted affair, with Perl doing the honours of reading and processing data stored in an XML file. It may seem an unsophisticated system, but it has worked well and, apart from the matter of server administration, I am in full control. Yes, there is a development and maintenance overhead, but I enjoy programming and scripting anyway; I just have to find the time for it. If this is not your idea of fun, then using a service like Flickr, Zooomr or Photobucket is attractive so long as things don't go awry as they have for Zooomr and all the bad publicity and user frustration can't have done Zooomr's future prospects any good at all.