Adventures & experiences in contemporary technology
One of my websites has an online photo gallery. This has been a long-term activity that has taken several forms over the years. Once HTML and JavaScript based, it then was powered by Perl before PHP and MySQL came along to take things from there.
While that remains how it works, the publishing side of things has used its own selection of mechanisms over the same time span. Perl and XML were the backbone until Python and Markdown took over. There was a time when ImageMagick and GraphicsMagick handled image processing, but Python now does that as well.
That was when the error message gracing the title of this post came to my notice. Everything was working well when executed in Spyder, but the message appears when I tried running things using Python on the command line. PIL is the abbreviated name for the Python 3 pillow package; there was one called PIL in the Python 2 days.
For me, pillow loads, resizes and creates new images, which is handy for adding borders and copyright/source information to each image as well as creating thumbnails. All this happens in memory and that makes everything go quickly, much faster than disk-based tools like ImageMagick and GraphicsMagick.
Of course, nothing is going to happen if the package cannot be loaded, and that is what the error message is about. Linux is what I mainly use, so that is the context for this scenario. What I was doing was something like the following in the Python script:
import PIL
Then, I referred to PIL.Image when I needed it, and this could not be found when the script was run from the command line (BASH). The solution was to add something like the following:
from PIL import Image
That sorted it, and I must have run into trouble with PIL.ImageFilter too, since I now load it in the same manner. In both cases, I could just refer to Image or ImageFilter as I required and without the dot syntax. However, you need to make sure that there is no clash with anything in another loaded Python package when doing this.
Since I created a bespoke theme for this site, I have been tweaking things as I go. The basis came from the WordPress Theme Developer Handbook, which gave me a simpler starting point shorn of all sorts of complexity that is encountered with other themes. Naturally, this means that there are little rough edges that need tidying over time.
One of these is dealing with errors on the site like when content is not found. This could be a wrong address or a search query that finds no matching posts. When that happens, there is a redirection to the home page using some simple JavaScript within the loop fallback code enclosed within script start and end tags (including the whole code triggers the action from this post so it cannot be shown here):
location.href="[blog home page ]";
The bloginfo function can be used with the url keyword to find the home page so this does not get hard coded. For now, this works so long as JavaScript is enabled but a more robust approach may come in time. It is not possible to do a PHP redirect because of the nature of HTTP: when headers have been sent, it is not possible to do server redirects. At this stage, things become client side so using JavaScript is one way to go instead.
GNOME 3.10 came out last month but it took until its inclusion into the Arch and Antergos repositories for me to see it in the flesh. Apart from the risk of instability, this is the sort of thing at which rolling distributions excel. They can give you a chance to see the latest software before it is included anywhere else. For the GNOME desktop environment, it might have meant awaiting the next release of Fedora in order to glimpse what is coming. This is not always a bad thing because Ubuntu GNOME seems to be sticking with using a release behind the latest version. With many GNOME Shell extension writers not updating their extensions until Fedora has caught up with the latest release of GNOME for a stable release, this is no bad thing and it means that a version of the desktop environment has been well bedded in by the time it reaches the world of Ubuntu too. Debian takes this even further by using a stable version from a few years ago and there is an argument in favour of that from a solidity perspective.
Being in the habit of kitting out GNOME Shell with extensions, I have a special interest in seeing which ones still work or could work with a little tweaking and those which have fallen from favour. In the top panel, the major change has been to replace the sound and user menus with a single aggregate menu. The user menu in particular has been in receipt of the attentions of extension writers and their efforts either need re-work or dropping after the latest development. The GNOME project seems to have picked up an annoying habit from WordPress in that the GNOME Shell API keeps changing and breaking extensions (plugins in the case of WordPress). There is one habit from the WordPress that needs copying though and that is with documentation, especially of that API for it is hardly anywhere to be found.
GNOME Shell theme developers don’t escape and a large border appeared around the panel when I used Elementary Luna 3.4 so I turned to XGnome Enhanced (found via GNOME-Look.org) instead. The former no longer is being maintained since the developer no longer uses GNOME Shell and has not got the same itch to scratch; maybe someone else could take it over because it worked well enough until 3.8? So far, the new theme works for me so that will be an option should there a move to GNOME 3.10 on one of my PC’s at some point in the future.
Returning to the subject of extensions, I had a go at seeing how the included Applications Menu extension works now since it wasn’t the most stable of items before. That has improved and it looks very usable too so I am not awaiting the updating of the Frippery equivalent. That the GNOME Shell backstage view has not moved on that much from how it was in 3.8 could be seen as a disappointed but the workaround will do just fine. Aside from the Frippery Applications Menu, there are other extensions that I use heavily that have yet to be updated for GNOME Shell 3.10. After a spot of success ahead of a possible upgrade to Ubuntu GNOME 13.10 and GNOME Shell 3.8 (though I remain with version 13.04 for now), I decided to see I could port a number of these to the latest version of the user interface. Below, you’ll find the results of my labours so feel free to make use of these updated items if you need them before they are update on the GNOME Shell Extensions website:
There have been more changes coming in GNOME 3.10 than GNOME Shell, which essentially is a JavaScript construction. The consolidation of application title bars in GNOME applications continues but a big exit button has appeared in the affected applications that wasn’t there before. Also there remains the possibility of applying the previously shared modifications to Nautilus (also known as Files) and a number of these usefully extend themselves to other applications such as Gedit too. Speaking of Gedit, this gains a very useful x of y numbering for the string searching functionality with x being the actual number of the occurrence of a certain piece of text in a file and y being its total number of occurrences.GNOME Tweak Tool has got an overhaul too and lost the setting that makes a folder path box appear in Nautilus instead of a location part, opening Dconf-Editor and going to org > gnome > nautilus > preferences and completing the tick box for always-use-location-entry will do the needful.
Essentially, the GNOME project is continuing along the path on which it set a few years ago. Though I would rather that GNOME Shell would be more mature, invasive changes are coming still and it leaves me wondering if or when this might stop. Maybe that was the consequence of mounting a controversial experiment when users were happy with what was there in GNOME 2. The arrival of Fedora 20 should bring with it an increase in the number of GNOME shell extensions that have been updated. So long as it remains stable Antergos is good have a look at the latest version of GNOME for now and Cinnamon fans may be pleased the Cinnamon 2.0 is another desktop option for the Arch-based distribution. An opportunity to say more about that may arrive yet once the Antergos installer stops failing at a troublesome package download; a separate VM is being set aside for a look at Cinnamon because it destabilised GNOME during a previous look.
With its final release being near at hand, I decided to have a look at the beta release of Ubuntu GNOME 13.10 to get a sense of what might be coming. A misstep along the way had me inadvertently download and install the 64-bit edition of 13.04 into a VirtualBox virtual machine. The intention to update that to its soon to be released successor was scuppered by instability so I never did get to try out an in situ upgrade to 13.10. What I had in mind was to issue the following command:
gksu update-manager -d
However, I found another one when considering how Ubuntu Server might be upgraded without the GUI application that is the Update Manager. To update to a development version, the following command is what you need:
sudo do-release-upgrade -d
To upgrade to a final release of of a new version of Ubuntu, drop the -d switch from the above to use the following:
sudo do-release-upgrade
There is one further option that isn’t recommended for moving between Ubuntu versions but I use it to get updates such as new kernel subversions that are released:
sudo apt-get dist-upgrade
Rather than trying out the above, I downloaded the latest ISO image for the beta release of Ubuntu GNOME 13.10 and installed onto a VM that instead. Though it is the 32 bit version of the distro that is installed on my main home PC, it has been the 64 bit version that I have been trying. So far, that seems to be behaving itself even if it feels a little sluggish but that could be down to the four year old PC that hosts the virtual machine. For a while, I have been playing with the possibility of an upgrade involving an Intel Core i5 4670K CPU and 16 GB of RAM (useful for running multiple virtual machines at a time) along with any motherboard that supports those so looking at a 64 bit operating system has its uses.
The Linux kernel may be 3.11 but that is not my biggest concern. Neither is the fact that LibreOffice 4.1.2.3 was included and GIMP wasn’t, especially when that could be added easily anyway and it is version 2.8.6 that you get. The move to GNOME Shell 3.8 was what drew me to seeing what was coming because I have been depending on a number extensions. As with WordPress and plugins, GNOME Shell seems to have a tempestuous relationship with some of its extensions and I wanted to see which ones still worked. There also has been a change to the backstage application view in that you either get all installed applications displayed when you browse them or you have to start typing the name of the one you want to select it. Losing the categorical view that has been there until GNOME Shell 3.6 is a step backwards and I hope that version 3.10 has seen some sort of a reinstatement. There is a way to add these categories and the result is not as it once was either; also, it shouldn’t be necessary for anyone to dive into a systems innards to address things like this. With all the constant change, it is little wonder that Cinnamon has become a standalone entity with the release of its version 2.0 and that Debian’s toyed with not going with GNOME for its latest version (7.1 at the time of writing and it picked a good GNOME Shell version in 3.4).
Having had a look at other distribution that already have GNOME Shell 3.8, I knew that a few of my extensions worked with it. The list includes Frippery Bottom Panel, Frippery Move Clock, Places Status Indicator, Removable Drive Menu, Remove Rounded Corners (not really needed with the GNOME Shell theme that I use, Elementary Luna 3.4, but I retain it anyway), Show Desktop Button, User Themes and Ignore_Request_Hide_Titlebar. Because of the changes to the backstage view, I added Frippery Applications Menu in preference to Applications Menu because I have found that to be unstable. Useful new discoveries have included Curtains Up and GNOME Shell Open Terminal while Shell Restart User Menu Entry has made a return and found a use this time around too.
There have been some extensions that were not updated to work with GNOME Shell 3.8 that I have got working. In some cases, it was as simple as updating the metadata.json file for an extension with new version numbers of 3.8 and 3.84 to the list associated with the shell version property. All extensions are to be found in the .local/share/gnome-shell/extensions location in your home directory and each has a dedicated file containing the aforementioned file.
With others, it was a matter of looking in the Looking Glass (execute lg in the box that ALT + F2 brings up on your screen to access this) and seeing what error messages were to be found in there before attempting to correct these in either the extensions’ extension.js files or whatever JavaScript (*.js) file was causing the problem. With either or both of these remedies, I managed to port the four extensions below to GNOME Shell 3.8. In fact, you can download these zip files and install them yourself to see how you get on with them.
Advanced Settings in User Menu
There is a Remove Panel App Menu that works with GNOME Shell 3.8 but I found that it got rid of the Places menu instead of the panel’s App Menu so I tried porting the older extension to see if it behaved itself and it does. With these in place, I have bent Ubuntu GNOME 13.10 to my will ahead of its final release next week and that includes customising Nautilus too. Other than a new version of GNOME Shell, it looks as if it will come with less in the way of drama and a breather like that is no bad thing given that personal computing continues to remain in a state of flux these days.
This is an error that I have started to see a lot in the last few weeks. First, it was with Piwik and latterly with WordPress.com Stats. For the record, I have never seen it on up to date systems but always with IE6 and at page unloading time. The CPU usage hits 100% before the error is produced and that has had me blaming JavaScript in error; it isn’t the cause of all ills. In fact, the cause seems to be a bug in a certain release of Adobe Flash 9 but I am of the opinion that the inclusion of certain features in a Flash movie are needed to trigger it too. I don’t have the exact details of this but WordPress.com Stats worked without fault until a recent update and that is what is making me reach the conclusion that I have. That observation is making me wonder whether we are coming to a point where Flash compatibility is something that needs to factored into the use of the said technology in a website or web application. Updating Flash will solve the problem on the client but it might be better if it wasn’t triggered on the server side either.
It amazes me now to think how little tracking I used to do on my various web “experiments” only a few short years ago. However, there was a time when a mere web counter, perhaps displayed on web pages themselves, was enough to yield some level of satisfaction, or dissatisfaction in many a case. Things have come a long way since then and we now seem to have analytics packages all around us. In fact, we don’t even have to dig into our pockets to get our hands on the means to peruse this sort of information either.
At this point, I need to admit that I am known to make use of a few simultaneously but thoughts about reducing their number are coming to mind but there’ll be more on that later. Given that this site is hosted using WordPress software, it should come as no surprise that Automattic’s own plugin has been set into action to see how things are going. The main focus is on the total number of visits by day, week and month with a breakdown showing what pages are doing well as well as an indication of how people came to the site and what links they followed while there. Don’t go expecting details of your visitors like the software that they are using and the country where they are accessing the site with this minimalist option and satisfaction should head your way.
There is next to no way of discussing the subject of website analytics without mentioning Google’s comprehensive offering in the area. You have to admit that it’s comprehensive with perhaps the only bugbear being the lack of live tracking. That need has been addressed very effectively by Woopra, even if its WordPress plugin will not work with IE6. Otherwise, you need the desktop application (being written in Java, it’s a cross-platform affair and I have had it going in both Windows and Linux) but that works well too. Apart maybe from the lack of campaigns, Woopra supplies as good as all of the information that its main competitor provides. It certainly doe what I would need from it.
However, while they can be free as in beer, there are a some costs associated with using using external services like Google Analytics and Woopra. Their means of tracking your web pages for you is by executing a piece of JavaScript that needs to be added to every page. If you have everything set to use a common header or footer page, that shouldn’t be too laborious and there are plugins for publishing platforms like WordPress too. This way of working means that if anyone has JavaScript disabled or decides not to enable JavaScript for the requisite hosts while using the NoScript extension with Firefox, then your numbers are scuppered. Saying that, the same concerns probably any JavaScript code that you may want to execute but there’s another cost again: the calls to external websites can, even with the best attention in the world, slow down the loading of your own pages. Not only is additional JavaScript being run but there also is the latency caused by servers having to communicate across the web.
A self-hosted analytics package would avoid the latter and I found one recently through Lifehacker. Amazingly, it has been around for a while and I hadn’t known about it but I can’t say that I was actively looking for it either. Piwik, formerly known as PHPMyVisites, is the name of my discovery and it seems not too immature either. In fact, I’d venture that it does next to everything that Google Analytics does. While I’d prefer that it used PHP, JavaScript is its means of tracking web pages too. Nevertheless, page loading is still faster than with Google Analytics and/or Woopra and Firefox/NoScript users would only have to allow JavaScript for one site too. If you have had experience with installing PHP/MySQL powered publishing platforms like WordPress, Textpattern and such like, then putting Piwik in place is no ordeal. You may find yourself changing folder access but uploading of the required files, the specification of database credentials and adding an administration user is all fairly standard stuff. I have the thing tracking this edifice as well as my outdoor activities (hillwalking/cycling/photography) web presence and I cannot say that I have any complaints so we’ll see how it goes from here.
I must admit that I have never been a great fan of JavaScript. For one thing, its need to interact with browser objects places you at the mercy of the purveyors of such pieces of software. Debugging is another fine art that can seem opaque to the the uninitiated since the amount and quality of the logging is determined an interpreter that isn’t provided by the language’s overseers. All in all, it seems to present a steep and obstacle-strewn learning curve to newcomers. As it happens, I have always found server side scripting languages like PHP and Perl to be more to my taste and I have no aversion at all to writing SQL.
In the late 1990’s when I was still using free web hosting, JavaScript probably was the best option for my then new online photo gallery. Whatever was the truth, it certainly was the way that I went. Learning Java or Flash might have been useful but I never managed to devote sufficient time to the task so JavaScript turned out to be the way forward until I got a taste of server side scripting. Moving to paid hosting allowed for that to develop and the JavaScript option took a back seat.
Based on my experience of the browser wars and working with JavaScript throughout their existence, I was more than a little surprised at the buzz surrounding AJAX. Ploughing part of the way through WROX’s Beginning AJAX did nothing to sell the technology to me; it came across as a very dry jargon-blighted read. Nevertheless, I do see the advantages of web applications being as responsive as their desktop equivalents but AJAX doesn’t always guarantee this; as someone that has seen such applications crawling on IE6, I can certainly vouch for this. In fact, I suspect that may be behind the appearance of technologies such as AIR and Silverlight so JavaScript may get usurped yet again, just like my move to a photo gallery powered on the server side.
Even with these concerns, using JavaScript to add a spot more interactivity is never a bad thing even if it can be overdone, hence the speed problems that I have witnessed. In fact, I have been known to use DOM scripting but I need to have the use in mind before I can experiment with a technology; I cannot do it the other way around. Nevertheless, I am keen to see what JavaScript libraries such as jQuery and Prototype might have to offer (both have been used in WordPress). I have happened on their respective websites so they might make good places to start and who knows where my curiosity might take me?
Following my move to Firefox 3, the BBC’s iPlayer became problematical again. I eventually sorted it after a fashion but I am noting an option for the frustrated before talking more about that. Finding the links to the ram files for the BBC’s Listen Again service can be a nightmare because of the Beeb’s reliance on JavaScript to cloak things up so it’s useful to find somewhere where things have been deconvoluted for us. That’s The Beebotron. It’s really meant for users of the mobile internet but it serves well for those times when a mismatch between Firefox and RealPlayer on Linux derails the more usual way to do things.
I gave myself a right old fright while tinkering with my hillwalking and photo gallery website. The problem stemmed from my use of window.onload to set up behaviours for web pages in a visitor information directory on the site. A lapse of concentration allowed me to associate an onload event handler with the body tags of the pages using a common header PHP script; another lapse also meant that my mistake was on public view for all to see because I uploaded files before I spotted the problem.
The result was that I was left wondering why the window.onload pieces weren’t working at all, something that seriously broke the pages. The mists of panic and bewilderment were cleared in good time by the realisation as what had happened: the body tag onload had overridden the window onload and rendered it inactive. I don’t know from where the thought arrived but it was the one that resolved the problems that I was seeing; it might be that I might have met it before in the dim and not-so-distance past.
Having your pages degrade gracefully for when a visitor has not enabled JavaScript or when you are foolish enough to break something like I did is definitely an asset, a point brought home to me by my salutary experience. I am not sure why I was willing to run the risk that I did but it now looks as if I need to include the task of adding improved graceful degradation to the to do list.
Looking through Google Analytics for my websites, I have always been struck by the lack of IE7 uptake seemingly apparent from the statistics. However, I recently discovered that there may be a reason for this. I use the Ultimate GA plugin with my WordPress blogs and that adds the JavaScript code block near the bottom of the page. However, I recently saw that giving me scripting errors in IE7 and a spot of manual coding saw it travel to the header section of the web page. That, and the deactivation of the said plugin, was sufficient to rid of the errors in question. Seeing the effect of my changes on the reported share of visitors using IE7 could be interesting. It might even boost the Vista numbers as well.