Adventures & experiences in contemporary technology
Recent curiosity about Java programming and Groovy scripting got me trying to start up the Eclipse IDE that I had install on my main machine. What I got instead of a successful application startup was a message that included the following:
!MESSAGE Exception launching the Eclipse Platform:
!STACK
java.lang.ClassNotFoundException: org.eclipse.core.runtime.adaptor.EclipseStarter
at java.base/java.net.URLClassLoader.findClass(URLClassLoader.java:466)
at java.base/java.lang.ClassLoader.loadClass(ClassLoader.java:566)
at java.base/java.lang.ClassLoader.loadClass(ClassLoader.java:499)
at org.eclipse.equinox.launcher.Main.invokeFramework(Main.java:626)
at org.eclipse.equinox.launcher.Main.basicRun(Main.java:584)
at org.eclipse.equinox.launcher.Main.run(Main.java:1438)
at org.eclipse.equinox.launcher.Main.main(Main.java:1414)
The cause was a mismatch between Eclipse and the installed version of Java that it needed in order to run. After all, the software itself is written in the Java language and the installed version from the usual software repositories was too old for Java 11. The solution turned out to be installing a newer version as a Snap (Ubuntu’s answer to Flatpak). The following command did the needful since Snapd already was running on my machine:
sudo snap install eclipse --classic
The only part of the command that warrants extra comment is the --classic switch since that is needed for a tool like Eclipse that needs to access a host file system. On executing, the software was downloaded from Snapcraft and then installed within its own bundle of dependencies. The latter adds a certain detachment from the underlying Linux installation and ensures that no messages appear because of incompatibilities like the one near the start of this post.
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.
Having made plenty of use of grep on the Linux/UNIX command and findstr on the legacy Windows command line, I wondered if PowerShell could be used to search the contents of files for a text string. Usefully, this turns out to be the case but I found that the native functionality does not use what I have used before. The form of the command is given below:
Select-String -Path <filename search expression> -Pattern "<search expression>" > <output file>
While you can have the output appear on screen, it always seems easier to send it to a file for subsequent and that is what I am doing above. The input to the -Path switch can be a filename or a wildcard expression while that to the -Pattern can be a text string enclosed in quotes or a regular expression. It works well once you know what to do so here is an example:
Select-String -Path *.sas -Pattern "proc report" > c:\temp\search.txt
The search.txt file then includes both the file information and the text that has been found for sake of checking that you have what you want. What you do next is up to you.
Because updating Piwik using its web interface has proved tempestuous, I have decided update the self-hosted analytics application an ssh session. The production web servers that I use are hosted on Linux systems so that is why any commands apply to the Linux or UNIX command line only. What is needed for Windows servers may differ.
The first step is to down the required ZIP file with this command:
wget https://builds.piwik.org/piwik.zip
Once the download is complete, the contents of the ZIP archive are extracted into a new subfolder. This is a process that I carry out in a separate folder to that where the website files are kept before copying everything from the extract folder in there. Here is the unzip command and the -o switch turns on overwriting of any previously existing files:
unzip -o piwik.zip
Without the requirement folder in web server area updated, the next step is to do the actual system update that includes any updates to the Piwik database that you are using. There are two commands that you can use once you have specified the location of your Piwik installation. The second is needed when the first option cannot find where the PHP executable is stored. My systems had something more specific than these because both PHP 5.6 and PHP 7.0 are installed. Looking in /usr/bin was enough to find what i needed to execute in place of php below. Otherwise, the command was the same.
./[path to piwik]/console core:update
php [path to piwik]/console core:update
While the upgrade is ongoing, it prompts you to permit it to continue before it goes and makes changes to the database. This did not take long on my systems but that depends on how much data there is. Once, the process has completed, you can delete any extraneous files using the rm command.
Recently, I managed to use 10AppsManager to remove most of the in-built apps from a Windows 10 virtual machine that I have for testing development versions in case anything ugly were to appear in a production update. Curiosity is my excuse for letting the tool do what it did and some could do with restoration. Out of the lot, Windows Store is the main one that I have sorted so far.
The first step of the process was to start up PowerShell in administrator mode. On my system, this is as simple as clicking on the relevant item in the menu popped up by right clicking on the Start Menu button and clicking on the Yes button in the dialogue box that appears afterwards. In your case, it might be a case of right clicking on the appropriate Start Menu programs entry, selecting the administrator option and going from there.
With this PowerShell session open, the first command to issue is the following:
Get-Appxpackage -Allusers > c:\temp\appxpackage.txt
This creates a listing of Windows app information and pops it into a text file in your choice of directory. Opening the text file in Notepad allows you to search it more easily and there is an entry for Windows Store:
Name : Microsoft.WindowsStore
Publisher : CN=Microsoft Corporation, O=Microsoft Corporation, L=Redmond, S=Washington, C=US
Architecture : X64
ResourceId :
Version : 11607.1001.32.0
PackageFullName : Microsoft.WindowsStore_11607.1001.32.0_x64__8wekyb3d8bbwe
InstallLocation : C:\Program Files\WindowsApps\Microsoft.WindowsStore_11607.1001.32.0_x64__8wekyb3d8bbwe
IsFramework : False
PackageFamilyName : Microsoft.WindowsStore_8wekyb3d8bbwe
PublisherId : 8wekyb3d8bbwe
PackageUserInformation : {S-1-5-21-3224249330-198124288-2558179248-1001
IsResourcePackage : False
IsBundle : False
IsDevelopmentMode : False
Dependencies : {Microsoft.VCLibs.140.00_14.0.24123.0_x64__8wekyb3d8bbwe,
Microsoft.NET.Native.Framework.1.3_1.3.24201.0_x64__8wekyb3d8bbwe,
Microsoft.NET.Native.Runtime.1.3_1.3.23901.0_x64__8wekyb3d8bbwe,
Microsoft.WindowsStore_11607.1001.32.0_neutral_split.scale-100_8wekyb3d8bbwe}
Using the information from the InstallLocation field, the following command can be built and executed (here, it has gone over several lines so you need to get your version onto a single one):
Add-AppxPackage -register “C:\Program Files\WindowsApps\Microsoft.WindowsStore_11607.1001.32.0_x64__8wekyb3d8bbwe\AppxManifest.xml” -DisableDevelopmentMode
Once the above has completed, the app was installed and ready to use again. As the mood took me, I installed other apps from the Windows Store as I saw fit.
Recently, I had a situation where my the VDI files for my Windows 10 virtual machine expanded in size all of a sudden and I needed to reduce them. My downloading maps for use with RouteBuddy may have been the cause so I moved the ISO installation files onto the underlying Linux Mint drives. With that space, I then set to uncovering how to compact the virtual disk file and the Sysinternals sdelete tool was recommended for clearing unused space. After downloading, I set it to work in a PowerShell session running on the guest operating system from its directory using the following command:
.\sdelete -z [drive letter designation; E: is an example]
From the command prompt, the following should do:
sdelete -z [drive letter designation; E: is an example]
Once, that had completed, I shut down the VM and executed a command like the following from a bash terminal session:
VBoxManage modifyhd [file location/file name].vdi --compact
Where there was space to release, VDI files were reduced in size to return more disk space. More could be done so I will look into the Windows 10 drives to see what else needs to be moved out of them.
In Windows 10, the preferred place to look if you fancy prompting an update of the system is in the Update & Security section of the Settings application. At the top is the Windows Update and the process usually is as simple as pressing the Check for updates button. For most of the time, that has been my experience but it stopped working on my main Windows 10 virtual machine so I needed to resolve the problem.
Initially, going into the Advanced Options section and deselecting the tick box for Give me updates for other Microsoft products when I update Windows helped but it seemed a non-ideal solution so I looked further. It was then that I found that manually resetting a system’s Windows Updates components helped others so I tried that and restarted the system.
The first part of the process was to right-click on the Start Menu button and select the Windows PowerShell (Admin) entry from the menu that appeared. This may be replaced by Command Prompt (Admin) on your system on your machine, but the next steps in the process are the same. In fact, you could include any commands you see below in a script file and execute that if you prefer. Here, I will run through each group in succession.
From either PowerShell or the Command Prompt, you need to stop the Windows Update, Cryptographic, BITS (or Background Intelligent Transfer Service) and MSI Installer services. To accomplish this, execute the following commands at a command prompt:
net stop wuauserv
net stop cryptSvc
net stop bits
net stop msiserver
With the services stopped, it is then possible to rename the SoftwareDistribution and Catroot2 folders so you can refresh everything to remove them. To accomplish this, execute the following pair of commands using either PowerShell or the Command Prompt:
ren C:\Windows\SoftwareDistribution SoftwareDistribution.old
ren C:\Windows\System32\catroot2 Catroot2.old
Once you have the folders renamed, then you can start the Windows Update, Cryptographic, BITS and MSI Installer services by executing the following commands in either PowerShell or the Command Prompt:
net start wuauserv
net start cryptSvc
net start bits
net start msiserver
Once these have completed, you may close the PowerShell or Command Prompt window that you were using and restart the machine. Going into the Update & Security section of the Settings tool afterwards and pressing the Check for updates button now builds new versions of the folders that you renamed and this takes a little while longer than the usual update process. Otherwise, you could let your system rebuild things in its own time. As it happens, I opted for manual intervention and all has worked well since then.
It seems that the Rename-Item commandlet in Powershell is a very useful tool when it comes to smarter renaming of files. Even text substitution is a possibility and what follows is an example that takes the output of the Dir command for listing the files in a directory and replaces hyphens with underscores in each one.
Dir | Rename-Item –NewName { $_.name –replace “-“,”_” }
The result is that something like the-file.txt becomes the_file.txt. This behaviour is reminiscent of the rename command found on Linux and UNIX systems, where regular expressions can be used like in the following example that has the same result as the above:
rename ‘s/-/_/g’ *
In both cases, you do need to be careful as to what files are in a directory for this though the wildcard syntax on Linux or UNIX will be more familiar who has worked with files via almost any command line. Another thing to watch in the UNIX world is that ** parses the whole directory structure and that could be something that is not wanted for much of the time.
All of this is a far cry from the capabilities of the ren or rename command used in the days of MS-DOS and what has become the legacy Windows command line. Apart from simple renaming, any attempt at tweaking a filename through substitution ended up with the extra string getting appended to filenames when I tried it. Thus, the Powershell option looks better in comparison.
The default PHP version on my outdoors, travel and photography website is 5.2.17 and that is getting on a bit now since it is no longer supported by the PHP project and has not been thus since 2011. One obvious impact was Piwik, which I used for web analytics and needs at least 5.3.2. WordPress 4.0 even needs 5.2.24 so that upgrade became implausible so I contacted Webfusion’s support team and they showed me how to get to at least 5.3.3 and even as far as 5.5.9. The trick is the addition of a line of code to the .htaccess file (near the top was my choice) like one of the following:
PHP 5.3.x
AddHandler application/x-httpd-php53 .php
PHP 5.5.x
AddHandler application/x-httpd-php55 .php
When I got one of these in place, things started to look promising but for a locked database due to my not watching how big it had got. Replacing it with two additional databases addressed the problem of losing write access though there was a little upheaval caused by this. Using PHP 5.5.9 meant that I spotted messages regarding the deprecation of the mysql_connect function so that needed fixing too (prefixing it with @ might be a temporary fix but a more permanent one always is better so that is what I did in the form of piggybacking off what WordPress uses; MySQLi and PDO_MySQL are other options). Sorting the database issue meant that I saw the upgrade message for WordPress as well as a mix of plugins and themes so all looked better and I need worry less about losing security updates. Also, I am up to the latest version of Piwik too and that’s an even better way to be.
There is a bill making its way through the U.K. parliament at the moment that could reduce the power of copyright when it comes to images placed on the web. The current situation is that anyone who creates an image automatically holds the copyright for it. However, the new legislation will remove that if it becomes law as it stands. As it happens, the Royal Photographic Society is doing what it can to avoid any changes to what we have now. There may be the barrier of due diligence but how many of us take steps to mark our own intellectual property? For one, I have been less that attentive to this and now wonder if there is anything more that I should be doing. Others may copyleft their images but I don’t want to find myself unable to share my own photos because another party is claiming rights over them. There’s watermarking them but I also want to add something to the image metadata too.
That got me wondering about adding metadata to any images that I post online that assert my status as the copyright holder. It may not be perfect but any action is better than doing nothing at all. Given that I don’t post photos where EXIF metadata is stripped as part of the uploading process, it should be there to see for anyone who bothers to check and there may not be many who do.
Because I also wanted to batch process images, I looked for a command line tool to do the needful and found ExifTool. Being a Perl library, it is cross-platform so you can use it on Linux, Windows and even OS X. To install it on a Debian or Ubuntu based Linux distro, just use the following command:
sudo apt-get install libimage-exiftool-perl
The form of the command that I found useful for adding the actual copyright information is below:
exiftool -p “-copyright=(c) John …” -ext jpg -overwrite_original
The -p switch preserves the timestamp of the image file while the -overwrite_original one ensures that you don’t end up with unwanted backup files. The copyright message goes within the quotes along with the -copyright option. With a little shell scripting, you can traverse a directory structure and change the metadata for any image files contained in different sub-folders. If you wish to do more than this, there’s always the user documentation to be consulted.