Technology Tales

Online learning

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.

Self-learning new computing languages

Over the years, I have taught myself a number of computing languages with some coming in useful for professional work while others came in handy for website development and maintenance. The collection has grown to include HTML, CSS, XML, Perl, PHP and UNIX Shell Scripting. The ongoing pandemic allowed to me added two more to the repertoire: R and Python.

My interest in these arose from my work as an information professional concerned with standardisation and automation of statistical results delivery. To date, the main focus has been on clinical study data but ongoing changes in the life sciences sector could mean that I may need to look further afield so having extra knowledge never hurts. Though I have been a SAS programmer for more than twenty years, its predominance in the clinical research field is not what it was so that I am having to rethink things.

As it happens, I would like to continue working with SAS since it does so much and thoughts of leaving it after me bring sadness. It also helps to know what the alternatives might be and to reject some management hopes about any newcomers, especially with regard to the amount of code being produced and the quality of graphs being created. Use cases need to be assessed dispassionately even when emotions loom behind the scenes.

Both R and Python bring large scripting ecosystems with active communities so the attraction of their adoption makes a deal of sense. SAS is comparable in the scale of its own ecosystem though there are considerable differences and the platform is catching up when it comes to Data Science. The aforementioned open source languages may have had a head start but it seems that others are not standing still either. It is a time to have wider awareness and online conference attendance helps with that.

The breadth of what is available for any programming language more than stymies any attempt to create a truly all encompassing starting point and I have abandoned thoughts of doing anything like that for R. Similarly, I will not even try such a thing for Python. Consequently, this means that my sharing of anything learned will be in the form of discrete postings from time to time, especially given ho easy it is to collect numerous website links for sharing.

The learning has been facilitated by ongoing pandemic restrictions though things are opening up a little now. The pandemic also has given us public data that can be used for practice since much can be gained from having one’s own project instead of completing exercises from a book. Having an interesting data set with which to work is a must and COVID-19 data contain a certain self-interest as well though one always is mindful of the suffering and loss of life that has been happening since the pandemic first took hold.

Fixing an update error in OpenMediaVault 4.0

For a time, I found that executing the command omv-update in OpenMediaVault 4.0 produced the following Python errors appeared among other more benign messages:

Exception ignored in: <function WeakValueDictionary.__init__.<locals>.remove at 0xb7099d64>
Traceback (most recent call last):
File "/usr/lib/python3.5/weakref.py", line 117, in remove
TypeError: 'NoneType' object is not callable
Exception ignored in: <function WeakValueDictionary.__init__.<locals>.remove at 0xb7099d64>
Traceback (most recent call last):
File "/usr/lib/python3.5/weakref.py", line 117, in remove
TypeError: 'NoneType' object is not callable

Not wanting a failed update, I decided that I needed to investigate this and found that /usr/lib/python3.5/weakref.py required the following updates to lines 109 and 117, respectively:

def remove(wr, selfref=ref(self), _atomic_removal=_remove_dead_weakref):

_atomic_removal(d, wr.key)

To be more clear, the line beginning with “def” is how line 109 should appear while the line beginning with _atomic_removal is how line 117 should appear. Once the required edits were made and the file closed, re-running omv-update revealed that the problem was fixed and that is how things remain at the time of writing.

Moving a website from shared hosting to a virtual private server

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.

Sorting out a system update failure for FreeBSD

With my tendency to apply Linux updates using the command, I was happy to see that something similar was possible in FreeBSD too. The first step is to fire up a terminal session and drop into root using the su command. That needs the root superuser password in order to continue and the next step is to update the local repositories using the following command:

pkg update

After that, it is time download updated packages and install these by issuing this command:

pkg upgrade

Most of the time, that is sufficient but I discovered that there are times when the above fails and additional interventions are needed. What I had uncovered were dependency error messages and I set to looking around the web for remedies to this. One forum question that was similar to what I had met with the suggestion of consulting the file called UPDATING in /usr/ports/. An answer like that looks unhelpful but for the inclusion of advice where extra actions were needed. Also, there is a useful article on updating FreeBSD ports that gives more in the way of background knowledge so you understand the more about what needs doing.

Following both that and the UPDATING  file resulted in my taking the following sequence of steps. The first act was to download and initialise the Ports Collection, a set of build instructions.

portsnap fetch extract

The above is a one time only action so future updates are done as follows:

portsnap fetch update

With an up to date Ports Collection in place, it was time to install portman:

pkg install portman

A look through /usr/ports/UPDTAING revealed the commands I needed for updating Python and Perl to address the dependency problem that I was having:

portmaster -o devel/py-setuptools27 devel/py-setuptools
portmaster -r py\*setuptools

With those completed, I re-ran pkg update again and all was well. The extra actions needed to get that result will not get forgotten and I am sharing them on here so I know where they are. If anyone else has use for them, that would be even better.

Running Internet Explorer on Linux

On first sight, this probably sounds daft given how good Firefox is but you cannot ignore those surfing the web using the ever pervasive Internet Explorer when doing some web development. Using virtualisation is a solution to the need but it can mean that you need to set up a web server with Perl, PHP, MySQL and the like in a virtual machine, all for a little offline testing and then there’s the potential for a lot of file copying too. Otherwise, you are trying to sneak things online and catch the glitches before anyone else does, never a good plan.

Therefore, having the ability to run IE to test your offline LAMPP set up is a boon and IES4Linux allows you to do what’s really needed. Naturally, WINE is involved, so some flakiness may be experienced, even after the ever useful API library’s reaching version 1. Otherwise, all usually runs well once you work your way through the very helpful instructions on the IES4Linux website. I did get a misplaced message about the version of WINE that I was using, and Python errors made a worrying appearance, but neither compromised the end result: a working IE6 installation on my main Ubuntu box.

IE5 and IE5.5 are also on offer if you’re interested but, after looking at my visitor statistics, I think that I can discount these. IE7 and the work-in-progress IE8 make no appearance on the availability list. The absence of IE7 is not a big problem as it might appear because coding for IE6 sufficiently suffices for IE7, even now; IE8 may not be the same in this regard but we shall see. Even so, a later browser release does mean a more secure version and I reckon that including IE7 should be next on the project’s to-do list. Saying that, what we have now is far better than nothing at all.