Adventures & experiences in contemporary technology
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.
There is a simple principal with the 7G Firewall from Perishable press: it is a set of mod_rewrite rules for the Apache web server that can be added to a .htaccess file and there also is a version for the Nginx web server as well. These check query strings, request Uniform Resource Identifiers (URI’s), user agents, remote hosts, HTTP referrers and request methods for any anomalies and blocks those that appear dubious.
Unfortunately, I found that the rules heavily slowed down a website with which I tried them so I am going have to wait until that is moved to a faster system before I really can give them a go. This can be a problem with security tools as I also found with adding a modsec jail to a Fail2Ban instance. As it happens, both sets of observations were made using the GTmetrix tool so it seems that there is a trade off between security and speed that needs to be assessed before adding anything to block unwanted web visitors.
During the summer, I discovered that Firefox was steadfastly opening on the same virtual desktop on Linux Mint (the Cinnamon version) regardless of the one on which it was started. Being a creature of habit who routinely opens Firefox within the same virtual desktop all the time, this was not something that I had noticed until the upheaval of a system rebuild. The supposed cause is setting the browser to reopen tabs from the preceding session. The settings change according to the version of Firefox but it is found in Settings > General in the version in which I am writing these words (Firefox Developer Edition 94.0b4) and the text beside the tick box is Open previous windows and tabs.
While disabling the aforementioned setting could work, there is another less intrusive solution. This needs the opening of a new tab and the entering of the address about:config in the address bar. If you see a warning message about the consequences of proceed further, accept responsibility using the interface as you do just that. In the resulting field marked Search preference name, enter the text widget.disable-workspace-management and toggle the setting from false to true in order to activate it. Then, Firefox should open on the desktop where you want it and not some other default location.
Things have been changing on here. Much of that has been behind the scenes with a move to a new VPS for extra speed and all the upheaval that brings. It also gained me a better system for less money than the old upgrade path was costing me and everything feels more responsive as well. Extra work has gone into securing the website as well and I have learned a lot as that has progressed. New lessons were added to older, and sometimes forgotten, ones.
The more obvious change for those who have been here before is that the visual appearance has been refreshed. A new theme has been applied with a multitude of tweaks to make it feel unique and to iron out any rough edges that there may be. This remains a WordPress-based website and new theme is a variant of the Appointee subtheme of the Appointment theme. WordPress does only supports child theming but not grandchild theming so I had to make a copy of Appointee of my own so I could modify things as I see fit.
To my eyes, things do look cleaner, crisper and brighter so I hope that it feels the same to you. Like so many designs these days, the basis is the Bootstrap framework and that is no bad thing in my mind though the standardisation may be too much for some tastes. What has become challenging is that it is getter harder to find new spins on more traditional layouts with everything going for a more magazine-like appearance and summaries being shown on the front page instead of complete articles. That probably reflects how things are going for websites these days so it may be that the next refresh could be more home grown and that is a while away yet.
As the website heads towards its sixteenth year, there is bound to be continuing change. In some ways, I prefer that some things remain unchanged so I use the classic editor instead of Gutenburg because that works best for me. Block-based editing is not for me since I prefer to tinker with code anyway. Still, not all of its influences can be avoided and I have needed to figure out the new widgets interface. It did not feel that intuitive but I suppose that I will grow accustomed to it.
My interest in technology continues even if it saddens me at time and some things do not impress me; the Windows 11 taskbar is one of those so I will not be in any hurry to move away from Windows 10. Still, the pandemic has offered its own learning with virtual conferencing allowing one to lurk and learn new things. For me, this has included R, Python, Julia and DevOps among other things. That proved worthwhile during a time with many restrictions. All that could yield more content yet and some already is on the way.
As ever, it is my own direct working with technology that yields some real niche ideas that others have not covered. With so many technology blogs out there, they may be getting less and less easy to find but everyone has their own journey so I hope to encounter more of them. There remain times when doing precedes telling and that is how it is on here. It is not all about appearances since content matters as much as it ever did.
Recently, I shared my thoughts on learning new computing languages by oneself using books, online research and personal practice. As successful as that can be, there remains a place for getting some actual instruction as well. Maybe that is why so many turn to YouTube, where there is a multitude of video channels offering such possibilities without cost. What I have also discovered is that this is complemented by a host of other providers whose services attract a fee, and there will be a few of those mentioned later in this post. Paying for online courses does mean that you can get the benefit of curation and an added assurance of quality in what appears to be a growing market.
The variation in quality can dog the YouTube approach, and it also can be tricky to find something good, even if the platform does suggest new videos based on what you have been watching. Much of what is found there does take the form of webinars from the likes of the Why R? Foundation, Posit or the NHSR Community. These can be useful, and there are shorter videos from such providers as the Association of Computing Machinery or SAS Users. These do help more if you already have some knowledge about the topic area being discussed, so they may not make the best starting points for someone who is starting from scratch.
Of course, working your way through a good book will help, and it is something that I have been known to do, but supplementing this with one or more video courses really adds to the experience and I have done a few of these on LinkedIn. That part of the professional platform came from the acquisition of Lynda.com and the topic areas range from soft skills like time management through to computing skills courses with R, SAS and Python seeing coverage among the data science portfolio. Even O’Reilly has ventured into the area in an expansion from the book publishing activities for which so many of us know the organisation.
The available online instructor community does not stop at the above since there are others like Degreed, Baeldung, Udacity, Programiz, Udemy, Business Science and Datanovia. Some of these tend towards online education provision that feels more like an online university course and those are numerous as well as you will find through Data Science Central or KDNuggets. Both of these earn income from advertising to pay for featured blog posts and newsletters, while the former also organises regular webinars and was my first port of call when I became curious about the world of data science during the autumn of 2017.
My point of approach into the world of online training has been as a freelance information professional needing to keep up to date with a rapidly changing field. The mix of content that is both free of charge and that which attracts a fee is one that can work. Both kinds do complement each other while possessing their unique advantages and disadvantages. The need to continually expand skills and knowledge never goes away, so it is well worth spending some time working what you are after, since you need to be sure that any training always adds to your own knowledge and skill level.
There are times when blogs cease to exist and the only place to find the content is on the Wayback Machine. Even then, it is in danger of being lost completely. One such example is the subject of this post.
Though this website makes use of the facilities of Cloudflare for various functions that include the blocking of image hotlinking, the same outcome can be achieved using .htaccess files on Apache web servers. It may work on Nginx to a point too but there are other configuration files that ought to be updated instead of using a .htaccess when some frown upon the approach. In any case, the lines that need adding to .htaccess are listed below though the web address needs to include your own domain in place of the dummy example provided:
RewriteEngine on
RewriteCond %{HTTP_REFERER} !^$
RewriteCond %{HTTP_REFERER} !^http://(www\.)?yourdomain.com(/)?.*$ [NC]
RewriteRule .*\.(gif|jpe?g|png|bmp)$ [F,NC]
The first line turns on the mod_rewrite engine and you may have that done anyway. Of course, the module needs enabling in your Apache configuration for this to work and you have to be allowed to perform the required action as well. This means changing the Apache configuration files. The next pair of lines look at the HTTP referer strings and the third one only allows images to be served from your own web domain and not others. To add more, you need to copy the third line and change the web address accordingly. Any new lines need to precede the last line that defines the file extensions that are to be blocked to other web addresses.
RewriteEngine on
RewriteCond %{HTTP_REFERER} !^$
RewriteCond %{HTTP_REFERER} !^http://(www\.)?yourdomain.com(/)?.*$ [NC]
RewriteRule \.(gif|jpe?g|png|bmp)$ /images/image.gif [L,NC]
Another variant of the previous code involves changing the last line to display a default image showing others what is happening. That may not reduce the bandwidth usage as much as complete blocking but it may be useful for telling others what is happening.
On checking the Site Health page of a WordPress blog, I saw errors that pointed to a problem with its SSL set up. The www subdomain was not included in the site’s certificate and was causing PHP errors as a result though they had no major effect on what visitors saw. Still, it was best to get rid of them so I needed to update the certificate as needed. Execution of a command like the following did the job:
sudo certbot --expand -d existing.com,www.example.com
Using a Let’s Encrypt certificate meant that I could use the certbot command since that already was installed on the server. The --expand and -d switches ensured that the listed domains were added to the certificate to sort out the observed problem. In the above, a dummy domain name is used but this was replaced by the real one to produce the desired effect and make things as they should have been.
When you set up your own web server or use a private server (virtual or physical), you will find that web servers run using the www-data account. That means that website files need to be accessible to that system account if not owned by it. The latter is mandatory if you you want WordPress to be able to update itself with needing FTP details.
It also means that you probably need scheduled jobs to be executed using the privileges possess by the www-data account. For instance, I use WP-CLI to automate spam removal and updates to plugins, themes and WordPress itself. Spam removal can be done without the www-data account but the updates need file access and cannot be completed without this. Therefore, I got interested in setting up cron jobs to run under that account and the following command helps to address this:
sudo -u www-data crontab -e
For that to work, your own account needs to be listed in /etc/sudoers or be assigned to the sudo group in /etc/group. If it is either of those, then entering your own password will open the cron file for www-data and it can be edited as for any other account. Closing and saving the session will update cron with the new job details.
In fact, the same approach can be taken for a variety of commands where files only can be access using www-data. This includes copying, pasting and deleting files as well as executing WP-CLI commands. The latter issues a striking message if you run a command using the root account, a pervasive temptation given what it allows. Any alternative to the latter has to be better from a security standpoint.
This year has seen some optimisation being applied to my web presences guided by the results of GTMetrix scans. It was then that I realised how slow things were, so server loads were reduced. Anything that slowed response times, such as WordPress plugins, got removed. Usage of Matomo also was curtailed in favour of Google Analytics while HTML, CSS and JS minification followed. What had yet to happen was a search for a faster server. Now, another website has been moved onto a virtual private server (VPS) to see how that would go.
Speed was not the only consideration since security was a factor too. After all, a VPS is more locked away from other users than a folder on a shared server. There also is the added sense of control, so Let’s Encrypt SSL certificates can be added using the Electronic Frontier Foundation’s Certbot. That avoids the expense of using an SSL certificate provided through my shared hosting provider and a successful transition for my travel website may mean that this one undergoes the same move.
For the VPS, I chose Ubuntu 18.04 as its operating system and it came with the LAMP stack already in place. Have offload development websites, the mix of Apache, MySQL and PHP is more familiar to me than anything using Nginx or Python. It also means that .htaccess files become more useful than they were on my previous Nginx-based platform. Having full access to the operating system by means of SSH helps too and should mean that I have fewer calls on technical support since I can do more for myself. Any extra tinkering should not affect others either, since this type of setup is well known to me and having an offline counterpart means that anything riskier is tried there beforehand.
Naturally, there were niggles to overcome with the move. The first to fix was to make the MySQL instance accept calls from outside the server so that I could migrate data there from elsewhere and I even got my shared hosting setup to start using the new database to see what performance boost it might give. To make all this happen, I first found the location of the relevant my.cnf configuration file using the following command:
find / -name my.cnf
Once I had the right file, I commented out the following line that it contained and restarted the database service afterwards using another command to stop the appearance of any error 111 messages:
bind-address 127.0.0.1
service mysql restart
After that, things worked as required and I moved onto another matter: uploading the requisite files. That meant installing an FTP server so I chose proftpd since I knew that well from previous tinkering. Once that was in place, file transfer commenced.
When that was done, I could do some testing to see if I had an active web server that loaded the website. Along the way, I also instated some Apache modules like mod-rewrite using the a2enmod command, restarting Apache each time I enabled another module.
Then, I discovered that Textpattern needed php-7.2-xml installed, so the following command was executed to do this:
apt install php7.2-xml
Then, the following line was uncommented in the correct php.ini configuration file that I found using the same method as that described already for the my.cnf configuration and that was followed by yet another Apache restart:
extension=php_xmlrpc.dll
Addressing the above issues yielded enough success for me to change the IP address in my Cloudflare dashboard so it pointed at the VPS and not the shared server. The changeover happened seamlessly without having to await DNS updates as once would have been the case. It had the added advantage of making both WordPress and Textpattern work fully.
With everything working to my satisfaction, I then followed the instructions on Certbot to set up my new Let’s Encrypt SSL certificate. Aside from a tweak to a configuration file and another Apache restart, the process was more automated than I had expected so I was ready to embark on some fine-tuning to embed the new security arrangements. That meant updating .htaccess files and Textpattern has its own, so the following addition was needed there:
RewriteCond %{HTTPS} !=on
RewriteRule ^ https://%{HTTP_HOST}%{REQUEST_URI} [R=301,L]
This complemented what was already in the main .htaccess file and WordPress allows you to include http(s) in the address it uses, so that was another task completed. The general .htaccess only needed the following lines to be added:
RewriteCond %{SERVER_PORT} 80
RewriteRule ^(.*)$ https://www.assortedexplorations.com/$1 [R,L]
What all these achieve is to redirect insecure connections to secure ones for every visitor to the website. After that, internal hyperlinks without https needed updating along with any forms so that a padlock sign could be shown for all pages.
With the main work completed, it was time to sort out a lingering niggle regarding the appearance of an FTP login page every time a WordPress installation or update was requested. The main solution was to make the web server account the owner of the files and directories, but the following line was added to wp-config.php as part of the fix even if it probably is not necessary:
define('FS_METHOD', 'direct');
There also was the non-operation of WP Cron and that was addressed using WP-CLI and a script from Bjorn Johansen. To make double sure of its effectiveness, the following was added to wp-config.php to turn off the usual WP-Cron behaviour:
define('DISABLE_WP_CRON', true);
Intriguingly, WP-CLI offers a long list of possible commands that are worth investigating. A few have been examined but more await attention.
Before those, I still need to get my new VPS to send emails. So far, sendmail has been installed, the hostname changed from localhost and the server restarted. More investigations are needed but what I have not is faster than what was there before, so the effort has been rewarded already.
On another website, I have had a contact form but it was missing some functionality. For instance, it stored the input in files on a web server instead of emailing them. That was fixed more easily than expected using the PHP mail function. Even so, it remains useful to survey corresponding documentation on the w3schools website.
The other changes affected the way the form looked to a visitor. There was a reset button and that was removed on finding that such things are out of favour these days. Thinking again, there hardly was any need for it any way.
Newer additions that came with HTML5 had their place too. Including user hints using the placeholder attribute should add some user friendliness although I have avoided experimenting with browser-powered input validation for now. Use of the required attribute has its uses for tell a visitor that they have forgotten something but I need to check how that is handled in CSS more thoroughly before I go with that since there are new :required, :optional, :valid and :invalid pseudoclasses that can be used to help.
It seems that there is much more to learn about setting up forms since I last checked. This is perhaps a hint that a few books need reading as part of catching with how things are done these days. There also is something new to learn.