HowTo: Reboot remote Windows computer with unresponsive RDP

I recently had an issue with an older Windows Server 2008 R2 server that couldn’t logout which had resulted to Remote Desktop not connecting to it anymore (not even with the “admin session” option). Luckily I had an admin go and physically cycle its power since it was a physial one without any lower level control available.

When the same issue occured at its twin machine, I decided before asking for another physical intervention to first try various other ways to reboot it remotely (e.g. via Windows Shutdown command and via the Computer Management console), but to no avail.

Eventually what worked was SysInternals PsShutdown tool. The syntax I used was:

PsShutdown –u AdminUserName –p AdminPassword –f –r \\MachineIPaddress

According to its command-line reference:

-u
Specifies optional user name for login to remote computer.

-p
Specifies optional password for user name. If you omit this you will be prompted to enter a hidden password.

-f
Forces all running applications to exit during the shutdown instead of giving them a chance to gracefully save their data.

-r
Reboot after shutdown.

I could maybe have used

-o
Logoff the console user.

instead of –r, but it didn’t help when I first tried without the –f option.

Guess if I had passed –f too in the first place with –o it might have worked, but it never hurts to do a reboot, unless you have any critical services you’re not sure will restart correctly. However, I would worry more about such a thing on a Unix machine rather than on a Windows one where periodic rebooting usually gives a “breath of fresh air” to the OS.

Most probably some application was preventing logoff, however I’d expect Remote Desktop / Terminal Service to be more robust in such a case.

Fix: javascript location.hash throttling issue with IFrame

I had implemented a simple (and most importantly working in older browsers too) way of communication between an IFrame and its parent page via location.replace(“#” + hash), which doesn’t add entries to history like location.hash=… does, and the onhashchange event, when I noticed Edge-Chromium was throwing a “Throttling navigation to prevent the browser from hanging.” error and the lon/lat fields I had on my test page wheren’t updating anymore when I was dragging quickly for a while my location picker marker on an OpenLayers map. If I released the marker and tried after a sec it was starting working again.

image

     

since the URL shown in the error message redirects to some page that has permission denied, I looked up a discussion that explained the “–disable-ipc-flooding-protection” Chromium switch to turn off that protection, however I was not having any loop in my code that was mentioned in that discussion as probable cause.
https://stackoverflow.com/questions/55925936/angular-7-throttling-navigation-to-prevent-the-browser-from-hanging

On Firefox there was a similar error but with other message:

image

Searching about it I read about the “debouncing” concept (to avoid flooding some API with consequtive requests too fast/often) at

https://stackoverflow.com/questions/45236692/angular-and-observale-how-to-avoid-multiple-requests-to-api-within-a-given-time

and

https://stackoverflow.com/questions/35991867/angular-2-using-observable-debounce-with-http-get

And ended up finding a simple implementation of it at

https://medium.com/@griffinmichl/implementing-debounce-in-javascript-eab51a12311e

that I adapted to run in older browsers (like IE11) too:

function debounce(func, wait) {
  var timeout;
  return function() {
    var context = this;
    var args = arguments;
    clearTimeout(timeout); //clear previous scheduled execution if still pending
    timeout = setTimeout(function() { func.apply(context, args); }, wait);
  }
}

function setLocationHash(hash) {
    window.location.replace("#" + hash); //don’t set window.location.hash directly, adds entries to browser history
}

setLocationHashDebounced = debounce(setLocationHash, 20);
    //this will make sure any setLocationHash calls that occur within 20msec replace any pending ones (all are timed to execute in steps of 20msec)

//…

function markersUpdated(otherLocations) { //callback
    theOtherLocations = otherLocations;
    if (theOtherLocations.length > 0) {
        var hash = theOtherLocations[0].toString();
        setLocationHashDebounced(hash);
    }
}

function hashChanged() {
    var hash = window.location.hash.substring(1);
    if (hash.length > 0) {
        var hashParts = hash.split(‘,’);
        if (hashParts.length >= 2){
            var location = [hashParts[0], hashParts[1]]; //[lon, lat]
            map_addOtherMarker(location); //Note: this will just move selected marker if existing and otherLocations.length = _maxOtherLocations > 0
             if (hashParts.length >= 3 && hashParts[2] == "zoom")
                 zoomToLocation(location);
        }
    }
}

Fix: WordPress not detecting updates, wp_options table corruption

I have been trying recently to troubleshoot a WordPress website that was not detecting available core and plugin updates. So I installed WordPress Debug Bar plugin and after enabling WP_DEBUG in wp-config.php I could open the Debug menu from the WordPress admin bar and see some errors being logged.

image

At the wp-content/wp-debug.log file that I had enabled to log wordpress errors, I could see entries like the following (in mixed Greek/English):

   
[26-Jan-2021 13:15:10 UTC] Σφάλμα Duplicate entry ‘113343’ for key ‘wp_options.PRIMARY’ βάσης δεδομένων WordPress για αίτηση INSERT INTO `wp_options` (`option_name`, `option_value`, `autoload`) VALUES (‘wt_cli_start_date’, ‘1611666910’, ‘yes’) ON DUPLICATE KEY UPDATE `option_name` = VALUES(`option_name`), `option_value` = VALUES(`option_value`), `autoload` = VALUES(`autoload`) από require(‘wp-load.php’), require_once(‘wp-config.php’), require_once(‘wp-settings.php’), include_once(‘/plugins/cookie-law-info/cookie-law-info.php’), run_cookie_law_info, Cookie_Law_Info->__construct, Cookie_Law_Info->load_dependencies, require_once(‘/plugins/cookie-law-info/includes/class-cookie-law-info-review_request.php’), Cookie_Law_Info_Review_Request->__construct, Cookie_Law_Info_Review_Request->check_condition, Cookie_Law_Info_Review_Request->reset_start_date, update_option, add_option

Checking the wp_options table with phpMyAdmin I didn’t see it having an option_id with such a value so I opened up the definition for that table from the sidebar and it seems PRIMARY is an index on that table, while the key is option_id as I originally though.

image

Did a new search on it and found this article

MySQL – Fix Error – WordPress Database Error Duplicate Entry for key PRIMARY for Query INSERT INTO wp_options – SQL Authority with Pinal Dave

from a guy I already trusted due to other nice articles on databases. It was as it seems a database corruption (guess the index is corrupted) and running

REPAIR TABLE wp_options

was enough to fix it.

So via phpMyAdmin’s SQL Code tab I executed that simple SQL command and suddenly Wordpess could find core and plugin updates again:

image

HowTo: install multiple Corel Painter brushpacks silently

I got a nice expression software charity bundle with Corel Painter 2020 (current version is 2021) and a bunch of brushes in it and then noticed that the brush packs where available for download as separate installers than the Painter software.

So I launched one of the brush pack installers from the command-line (can give CMD and press enter at the address bar of the file explorer window to open command-line in the current folder) with a /? parameter to see its syntax:

e:\brushpack_abstract_windows.exe /?

image

Then I created a batch file to loop over all the brush_* installer files using the following commands in the console (press ENTER after each one). The for loop executes each brush pack installer from the same folder passing parameters for silent mode (/S /v/qn), as instructed by the dialog above:

copy con PainterInstallBrushes.bat
@for %%f in (brushpack_*) do %%f /S /v/qn

^Z

The last one (^Z) means Press CTRL+Z (then press ENTER for that line too). It signifies the end-of-file / input. We were inputing/copying keystrokes from the console (CON) into the file PainterInstallBrushes.bat (note that if the file exists you’re asked to overwrite it as soon as you copy the 1st line into it, but you still have to press CTRL+Z and ENTER to end input).

To avoid having to press Yes at repeated security dialogs (due to User Access Control [UAC] being activated), I opened an administrator command-prompt (can give CMD at Windows search and right click the found cmd.exe and select to open it as administrator), then executed the batch file (E: goes to drive E, CD \Corel.com goes to Corel.com folder under E: drive root)

c:\windows\system32> e:
e:\somefolder> cd \Corel.com
e:\Corel.com> PainterInstallBrushes.bat

e:\Corel.com>PainterInstallBrushes.bat

e:\Corel.com>brushpack_abstract_windows.exe /S /v/qn

e:\Corel.com>brushpack_alcoholink_windows.exe /S /v/qn

e:\Corel.com>brushpack_bristly_windows.exe /S /v/qn

e:\Corel.com>brushpack_bubbles_windows.exe /S /v/qn

e:\Corel.com>brushpack_drytexture_windows.exe /S /v/qn

e:\Corel.com>brushpack_feather_windows.exe /S /v/qn

e:\Corel.com>brushpack_fireworks_windows.exe /S /v/qn

e:\Corel.com>brushpack_gesturalillustration_windows.exe /S /v/qn

e:\Corel.com>brushpack_mangaii_windows.exe /S /v/qn

e:\Corel.com>brushpack_michellewebbmasterpack_windows.exe /S /v/qn

e:\Corel.com>brushpack_nature_windows.exe /S /v/qn

e:\Corel.com>brushpack_perfectpets_windows.exe /S /v/qn

e:\Corel.com>brushpack_popart_windows.exe /S /v/qn

e:\Corel.com>brushpack_rain_windows.exe /S /v/qn

e:\Corel.com>brushpack_rake_windows.exe /S /v/qn

e:\Corel.com>brushpack_rustandpatina_windows.exe /S /v/qn

e:\Corel.com>brushpack_scrape_windows.exe /S /v/qn

e:\Corel.com>brushpack_stipple_windows.exe /S /v/qn

e:\Corel.com>brushpack_suminagashi_windows.exe /S /v/qn

e:\Corel.com>brushpack_sunnyrays_windows.exe /S /v/qn

An alternative way to using the command-line would have been to create the batch (.bat) file with a text editor in the same folder as the brush pack installers, then right click it and select to run it as an administrator from the popup menu.

HowTo: Extract numeric suffix from a string in Python

I recently needed to extract a numeric suffix from a string value in Python. Initially I did the following:

import re

def extractNumSuffix(value):

    return (None if (search:=re.search(‘^\D*(\d+)$’, value, re.IGNORECASE)) is None else search.group(1))

Note that return has a single-line expression.

So

print(extractNumSuffix("test1030"))

prints 1030

Tried it online at:

https://repl.it/languages/python3

extractNumSuffix

However, then I found out that Assignment Expressions in Python only work from Python 3.8 and up, so I changed it to this one:

import re

def extractNumSuffix(value):
    search=re.search(r"^\D*(\d+)$", value, re.IGNORECASE)
    return (None if search is None else search.group(1))

which should work in Python 2.x too. Don’t forget to import the regular expressions (re) module.

HowTo: Install Python, PIP and cx_Oracle on MSYS2 / Windows

Here’s how to install Python, PIP package installer and cx_Oracle extension module on MSYS2:

$ pacman -S python
warning: python-3.8.3-1 is up to date — reinstalling
resolving dependencies…
looking for conflicting packages…

Packages (1) python-3.8.3-1

Total Installed Size:  108.66 MiB
Net Upgrade Size:        0.00 MiB

:: Proceed with installation? [Y/n] y

$ pacman -S cx_Oracle
error: target not found: cx_Oracle

$ pip install cx_Oracle
bash: pip: command not found

$ pacman -S python-pip
resolving dependencies…
looking for conflicting packages…

Packages (2) python-setuptools-47.1.1-1  python-pip-20.1.1-1

Total Download Size:    2.22 MiB
Total Installed Size:  10.91 MiB

:: Proceed with installation? [Y/n] y
:: Retrieving packages…

$ pip install cx_Oracle
Collecting cx_Oracle
  Downloading cx_Oracle-8.0.0.tar.gz (325 kB)
     |████████████████████████████████| 325 kB 693 kB/s
Using legacy setup.py install for cx-Oracle, since package ‘wheel’ is not installed.
Installing collected packages: cx-Oracle
    Running setup.py install for cx-Oracle … error
    ERROR: Command errored out with exit status 1:
     command: /usr/bin/python3.exe -u -c ‘import sys, setuptools, tokenize; sys.argv[0] = ‘"’"’/tmp/pip-install-wqtzv2rv/cx-Oracle/setup.py’"’"’; __file__=’"’"’/tmp/pip-install-wqtzv2rv/cx-Oracle/setup.py’"’"’;f=getattr(tokenize, ‘"’"’open’"’"’, open)(__file__);code=f.read().replace(‘"’"’\r\n’"’"’, ‘"’"’\n’"’"’);f.close();exec(compile(code, __file__, ‘"’"’exec’"’"’))’ install –record /tmp/pip-record-mui2mjs9/install-record.txt –single-version-externally-managed –compile –install-headers /usr/include/python3.8/cx-Oracle
         cwd: /tmp/pip-install-wqtzv2rv/cx-Oracle/
    Complete output (17 lines):
    running install
    running build
    running build_ext
    building ‘cx_Oracle’ extension
    creating build
    creating build/temp.msys-3.1.5-x86_64-3.8
    creating build/temp.msys-3.1.5-x86_64-3.8/src
    creating build/temp.msys-3.1.5-x86_64-3.8/odpi
    creating build/temp.msys-3.1.5-x86_64-3.8/odpi/src
    x86_64-pc-msys-gcc -Wno-unused-result -Wsign-compare -DNDEBUG -g -fwrapv -O3 -Wall -march=x86-64 -mtune=generic -O2 -pipe -march=x86-64 -mtune=generic -O2 -pipe -march=x86-64 -mtune=generic -O2 -pipe -DCXO_BUILD_VERSION=8.0.0 -Iodpi/include -Iodpi/src -I/usr/include/python3.8 -c src/cxoApiType.c -o build/temp.msys-3.1.5-x86_64-3.8/src/cxoApiType.o
    In file included from src/cxoModule.h:14,
                     from src/cxoApiType.c:11:
    /usr/include/python3.8/Python.h:44:10: fatal error: crypt.h: No such file or directory
       44 | #include <crypt.h>
          |          ^~~~~~~~~
    compilation terminated.
    error: command ‘x86_64-pc-msys-gcc’ failed with exit status 1
    —————————————-
ERROR: Command errored out with exit status 1: /usr/bin/python3.exe -u -c ‘import sys, setuptools, tokenize; sys.argv[0] = ‘"’"’/tmp/pip-install-wqtzv2rv/cx-Oracle/setup.py’"’"’; __file__=’"’"’/tmp/pip-install-wqtzv2rv/cx-Oracle/setup.py’"’"’;f=getattr(tokenize, ‘"’"’open’"’"’, open)(__file__);code=f.read().replace(‘"’"’\r\n’"’"’, ‘"’"’\n’"’"’);f.close();exec(compile(code, __file__, ‘"’"’exec’"’"’))’ install –record /tmp/pip-record-mui2mjs9/install-record.txt –single-version-externally-managed –compile –install-headers /usr/include/python3.8/cx-Oracle Check the logs for full command output.

Found a solution here for other Linuxes, mentioning

apt install python-dev clang libcrypt-dev

Via MSYS2 package manager (pacman), libcrypt and libcrypt-devel seem to be available. The second one should fetch the first one if needed, together with header files for development.

$ pacman -S libcrypt-devel
resolving dependencies…
looking for conflicting packages…

Packages (1) libcrypt-devel-2.1-2

Total Download Size:   0.04 MiB
Total Installed Size:  0.04 MiB

:: Proceed with installation? [Y/n] y

Now we can install cx_Oracle succesfully:

$ pip install cx_Oracle
Collecting cx_Oracle
  Using cached cx_Oracle-8.0.0.tar.gz (325 kB)
Using legacy setup.py install for cx-Oracle, since package ‘wheel’ is not installed.
Installing collected packages: cx-Oracle
    Running setup.py install for cx-Oracle … done
Successfully installed cx-Oracle-8.0.0

Using cross-platform fswatch utility for monitoring file system changes

I was just looking for a way to monitor for file system changs in a cross-platform way.

After searching the answers at a related question on StackExchange and the ones at the other question mentioned as possible duplicate in that question’s comments, I think I’d go with fswatch since it is has cross-platform support. Contributed the following answer to collect info I gathered on fswatch.

It uses different kinds of monitors for different OS and can choose the appropriate one automatically, or allow one to specify which one to use and even pass custom platform-specific parameters to the respective monitor.

The list of monitors it currently supports is:

· A monitor based on the File System Events API of Apple OS X.

· A monitor based on kqueue, an event notification interface introduced in FreeBSD 4.1 and supported on most *BSD systems (including OS X).

· A monitor based on inotify, a Linux kernel subsystem that reports file system changes to applications.

· A monitor based on File Events Notification, a Solaris/Illumos kernel API that reports file events.

· A monitor based on ReadDirectoryChangesW, a Microsoft Windows API that reports changes to a directory.

· A monitor which periodically stats the file system, saves file modification times in memory and manually calculates file system changes, which can work on any operating system where stat (2) can be used.

It seems to be available via apt-get on Debian/Ubuntu Linuxes. See how to install via apt-get and use fswatch.

FreeBSD and OS-X package-based installation support for fswatch is provided by its author.

Can also build and install it at other OSes, found an article+video showing how to make and install fswatch on CentOS.

There is also an other article that shows the same manual process to build/install (and use) fswatch for Linux.

Windows-based package-based installation support doesn’t seem to be available yet (e.g. no package for Chocolatey yet, and no package for Vcpkg)

There is also extensive documentation for fswatch, though docs for the latest 1.5 version point to 1.4 ones currently. See how to convert commands for fswatch 0.x to fswatch 1.x

Tips for manually choosing a monitor (currently not updated to mention all monitors)

Read about fswatch usage here, here and here and a tutorial intro here

A library named libfswatch is kept in sync with the fswatch tool. See here and a newer doc here. Note that the library is versioned differently from fswatch utility itself. Specifically, the 1.14.0 library doc states:

"libtool’s versioning scheme is described by three integers: current:revision:age.

· current is the most recent interface number implemented by the library.

· revision is the implementation number of the current interface.

· age is the difference between the newest and the oldest interface that the library implements.

Beware that there is also another similar s/w called fswatch (that is go-related I think).

Python rstrip and whitespace

Was just reading

https://www.w3schools.com/python/ref_string_rstrip.asp

which says

The rstrip() method removes any trailing characters (characters at the end a string), space is the default trailing character to remove.

Notes:

1) the chars param was added at Python 2.2.3, can’t use it at older versions as noted at

https://docs.python.org/2.6/library/string.html

string.rstrip(s[, chars])
Return a copy of the string with trailing characters removed. If chars is omitted or None, whitespace characters are removed. If given and not None, chars must be a string; the characters in the string will be stripped from the end of the string this method is called on.

Changed in version 2.2.3: The chars parameter was added. The chars parameter cannot be passed in earlier 2.2 versions.

2) from the official doc and other docs too I read the default is to remove whitespace characters, not just the space char:

https://python-reference.readthedocs.io/en/latest/docs/str/rstrip.html

chars
Optional. String specifying the set of characters to be removed. If omitted or None, the chars argument defaults to removing whitespace. The chars argument is not a prefix; rather, all combinations of its values are stripped.

Not sure what is considered whitespace in various Python versions though. At least in Python2 it wasn’t removing \r in both Solaris and MSYS2 (a POSIX environment on Windows) where I just tried.

For example, I was just debugging some program that was working in Python 3, but in Python 2 it was moving the cursor to the start of the line when printing a raw_input prompt with some string it had read before…
…the issue proved to be that it was opening a file with ‘r’ mode instead of ‘rU’ which is universal newlines mode – https://www.python.org/dev/peps/pep-0278/ – converts \r\n to \n – and it seems that rstrip was failing to remove the \r from the end of those strings.

In Python 3 it was either using the universal newlines mode by default and thus stripping the \r from strings while reading from the file, or the rstrip was removing \r too in Python3, but I guess it was the 1st case (didn’t do any more check since the universal newlines read file open mode fixed the issue in Python 2 for me).

Speaking of that, I wonder whether Python considers whitespace differently on Windows and on Unixes (aka having [l/r]strip commands remove \r on the 1st but not on the 2nd case), which would be an extra complexity when writing portable s/w.

HowTo: make raw_input & input work the same in both Python 2 and 3

Was just trying to make a Python 2 script work in Python 3 and at first it seemed I just needed a small change to add missing parentheses to the argument of a couple of print statements.

But then another issue came up, it wasn’t understanding the command raw_input(somePrompt) that was occuring at various places in that file to input text from the console.

Various solutions were proposed at

https://stackoverflow.com/questions/954834/how-do-i-use-raw-input-in-python-3/62825723

but I think I came up with a cleaner looking solution that works in both Python2 and Python3, that should allow one to use either raw_input or input in both Python2 and Python3 with the semantics of Python2’s raw_input (aka the semantics of Python3’s input).

# raw_input isn't defined in Python3.x, whereas input wasn't behaving 
# like raw_input in Python 2.x. This should make both input and raw_input 
# work in Python 2.x/3.x like the raw_input from Python 2.x 
try: input = raw_input
except NameError: raw_input = input

In practice this came up from ideas at other answers on that SO thread. It tries to define input as raw_input which should fail in Python3.x since raw_input is undefined. In that case it will catch a NameError exception and do the reverse, aka define raw_input as input. However in Python2 the first command should execute fine, overriding the insecure input of Python2.x to work the same as raw_input (not trying to interpret input strings that is). Actually that is what Python 3.x input does.

Wonder why they didn’t declare it like that in the first place though, breaking compilation of Python2 programs. After all semantically only Python2 programs that were using the old insecure input would have an issue, not those that were using raw_input which is the semantics Python3 promotes with its newer input.

HowTo: Use DISM and SFC tools to check+fix your Windows installation

If you’re having issues with your Windows 7 or newer, you should consider whether its installation has become corrupted (due to malicious software or hard drive errors).

After doing a disk check (say by right clicking the appropriate drive under my computer and selecting Properties, then Tools tab and Error checking) and a complete virus scan (on Win10 you can click the shield icon of Windows defender in the taskbar tray and at scanning options choose to do a full scan – or if you have installed some third-party antivirus double-click its icon in the taskbar tray and when its GUI opens up opt to do a full scan), then try the following steps to repair your Windows installation:

1. Press WIN+R to open Run dialog

2. Type in:

CMD

Hold down CTRL+SHIFT keys and click OK to open the command line window in Administrator mode (do press Yes at the User Account Control prompt)

A (usually) black text-based console window will open up and you’ll be greated with something like:

Microsoft Windows [Version 10.0.18363.720]
(c) 2019 Microsoft Corporation. All rights reserved.

and then a prompt like:

C:\Windows\system32>

3. Type in the following and press the ENTER key:

DISM.exe /Online /Cleanup-image /Scanhealth

and press ENTER to execute the DISM tool with the option to check the windows image health and wait patiently for it to complete

Deployment Image Servicing and Management tool
Version: 10.0.18362.1

Image Version: 10.0.18363.720

[==========================100.0%==========================] The component store is repairable.
The operation completed successfully.

4. In case you see a message that the component store is repairable, then when greeted with the C:\Windows\system32> prompt again, type in the following and press ENTER:

DISM.exe /Online /Cleanup-image /RestoreHealth

to repair the Windows image:

Deployment Image Servicing and Management tool
Version: 10.0.18362.1

Image Version: 10.0.18363.720

[==========================100.0%==========================] The restore operation completed successfully.
The operation completed successfully.

If RestoreHealth fails and you’re on Windows 10, then you should checkout this article:

https://www.tenforums.com/tutorials/16397-repair-install-windows-10-place-upgrade.html

on how to do an in place upgrade of Windows 10, opting to keep your settings and apps

5. If all goes well you’ll see that the restore operation completed successfully and you’ll be taken again to the command-line prompt C:\Windows\system32>

Now that the windows image is checked and fine, you should check your Windows installation against that image, giving the following command and pressing ENTER:

sfc /scannow

Beginning system scan.  This process will take some time.

Beginning verification phase of system scan.
Verification 100% complete.

Windows Resource Protection found corrupt files and successfully repaired them.
For online repairs, details are included in the CBS log file located at
windir\Logs\CBS\CBS.log. For example C:\Windows\Logs\CBS\CBS.log. For offline
repairs, details are included in the log file provided by the /OFFLOGFILE flag.

After any automatic repairs you should see the prompt C:\Windows\system32> again. Now repeat the same step till you see no more errors found and repaired.

sfc /scannow

Beginning system scan.  This process will take some time.

Beginning verification phase of system scan.
Verification 100% complete.

Windows Resource Protection did not find any integrity violations.

When back at the C:\Windows\system32> prompt with no errors found and repaired, just close the console window or type in the following and press ENTER:

exit

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