screaming.computer

Secure Socket Layer

Fri, 22 Dec 2023 16:07:37 GMT

This SCREAMING.COMPUTER website finally has an SSL certificate, which means you can access it using HTTPS, like any well-behaved site in 2023!

The old HTTP version is still accessible, but HTTPS is the new default. This should make Google happier (it seems to downrank non-SSL sites) as well as being better supported in all modern web browsers.

If you have any http://screaming.computer bookmarks, go ahead and add a little ‘S’ to upgrade to the secure site: https://screaming.computer.

Random Garfield Comic Titles

Sun, 17 Dec 2023 09:18:07 GMT

Let's generate some random no-name Garfield comics.

To begin, we need an unsettlingly-derivative name for the cat, and a suitable subtitle. We're really leaning in to the ‘discount,’ ‘dollar-store,’ “we have Garfield at home” aspect of these titles.

Let's use the proper Garfield fonts, “Alfredo Heavy Regular” for the title and “Garfield Regular” for the tagline:

Then of course we resize to the receipt printer width and crunch it down with 1-bit dithering:

The name-generation algorithm is rather carefully thought-out... we want maximum weirdness while maintaining similarity to the original name (hence the score variable). Cadence and syllables all factor in to the word components.

Notice the weighted-random tagging appended to each string value, which specifies the relative likelihood that any given item will be chosen.

function GarfTaglineGenerate() : string
{
    $tag = '';
    $tag .= WeightedStringRand (array ('lazy|2', 'fat|2', 'hungry|2', 'grumpy|2', 'pampered|1', 'sarcastic|1', 'overweight|1', 'comical|1', 'furry|1', 'funny|1', 'amusing|1', 'clever|1')) . ' ';
    $tag .= WeightedStringRand (array ('cat|6', 'feline|5', 'pet|4', 'animal|4', 'cartoon|3', 'creature|2', 'character|1'));
    return ($tag);
}

function GarfNameGenerate() : string
{
    do
    {
        $name = '';
        $score = 0;

        // --- G ----
        $name .= ($part = WeightedStringRand (array ('G|10', 'X|0', 'D|2', 'F|2', 'B|2', 'R|1', 'J|2')));
        if ($part == 'G')
            $score += 2;

        // --- . ----
        $part = WeightedStringRand (array ('|10', 'r|2', 'w|1', 'l|2'));
        if ($part == '' || mb_endswithi ($name, $part) || in_array ($name . $part, array ('Xw', 'Rw', 'Jw', 'Fw', 'Bw', 'Xr', 'Jr', 'Rl', 'Xl', 'Dl', 'Jl')))
            $score++;
        else
            $name .= $part;

        // --- a ----
        $name .= ($part = WeightedStringRand (array ('a|5', 'e|2', 'i|1', 'o|2', 'u|1')));
        if ($part == 'a')
            $score++;

        // --- r ----
        $name .= ($part = WeightedStringRand (array ('r|5', 'n|2', 'l|2', 's|2', 'd|2', 't|2', 'b|2', 'k|2', 'm|2', 'g|1', 'f|1', 'z|1', 'x|1', 'p|1', '|1')));
        if ($part == 'r')
            $score++;

        // --- f ----
        do   {
            $part = WeightedStringRand (array ('f|10', 'd|2', 'g|2', 's|2', 'n|2', 't|2', 'b|2', 'k|2', 'm|2', 'g|1', 'z|1', 'x|0', 'p|1', 'ph|1', 'sh|1'));
        } while (($part != 'f' && mb_endswithi ($name, mb_firstchar ($part)))
                || in_array (mb_lastchar ($name) . $part, array ('zs', 'zsh', 'sz', 'xz', 'xs', 'xsh')));
        $name .= $part;
        if ($part == 'f')
            $score += 3;

        // --- ie ----
        $name .= ($part = WeightedStringRand (array ('ie|5', 'ee|3', 'oo|2', 'ae|0', 'ou|1', 'a|2', 'e|3', 'i|3', 'o|2', 'u|2')));
        if ($part == 'ie')
            $score += 2;
        else if (in_array ($part, array ('ee', 'e', 'i')))
            $score++;

        // --- ld ----
        $name .= ($part = WeightedStringRand (array ('ld|5', 'd|3', 'g|3', 'lk|2', 'ng|2', 'nk|2', 'k|2', 'rk|2', 'rd|2', 'rf|2', 'lt|2', 't|2', 'nd|2', 'nt|2',
                                                    'rds|1', 'pt|1', 'md|0', 'r|1', 's|1', 'ss|1', 'ck|1', 'll|1')));
        if ($part == 'ld')
            $score += 3;
        else if (mb_lastchar ($part) == 'd')
            $score += 2;

    } while ($score < 7 || mb_containsanyi ($name, array (
            'garfield', 'iemd', 'rir', 'rur', 'ooll', 'eell', 'eeld', 'oold',
            'god', 'denied', 'golfing', 'golfer', 'refund', 'getfound', 'gunfiend', 'food', 'feed', 'girl', 'barf',
            'damn', 'piss', 'fuck', 'shit', 'dick', 'cunt', 'kunt', 'fag', 'porn', 'suck', 'jiz', 'homo', 'poop', 'cock', 'rape', 'kill', 'drug', 'ass', 'gook'))
            || mb_startsanyi ($name, array ('fat', 'fap', 'gag', 'dad', 'jap', 'bad'))
            || mb_endsanyi   ($name, array ('fat', 'find')));

    return ($name);
}

As a final step we also must filter out inappropriate words and substrings from the random results. Some filters just clear out awkward sequences of consonants and vowels, while others filter out hateful terms and inappropriate sexual references. It's a bit weird to have to put these phrases into code, but it's necessary to produce sanitized results.

The support functions should be obvious, but the full source code, plus fonts are available for download for reference.

Observe some potential results from the random title generator:

Gazfink, the grumpy animal
Gemfield, the lazy feline
Berfuld, the overweight animal
Gerzold, the grumpy pet
Glunfeld, the lazy cat
Forfild, the clever creature
Gapfeek, the hungry animal
Donfield, the lazy cartoon
Gufieg, the comical pet
Gamberd, the clever feline
Rarfing, the fat pet
Gazfeeg, the fat cat
Gamfarf, the pampered creature
Garfierf, the fat cartoon
Gapfipt, the clever cat
Jorfurd, the amusing cat
Gamdeed, the clever animal
Gokfilk, the grumpy cartoon
Gerfouss, the amusing cat
Gizfeld, the lazy creature
Gofieg, the pampered pet
Jarkild, the grumpy cat
Glatfeeg, the overweight animal
Gerfeeng, the furry pet
Faffiet, the fat feline
Gafet, the grumpy pet
Gonfierds, the comical character
Ganshild, the fat cat
Grarfied, the grumpy creature
Danfod, the fat feline

All-in-all, there are approximately 45,000 possible names, plus 84 unique subtitles. Seems like a good start for a random Garfield generator.

[UPDATED] Set up a LAMP server VM in UnRAID

Sun, 24 Sep 2023 23:39:52 GMT

Guide v6.4 / Updated 2023-11-24 / First published 2023-09-24 / echo (at) screaming (dot) computer

This is an updated version of the original LAMP server VM in UnRAID setup guide.
New in this version: LTS release of Linux Mint; upgrade to PHP 8; switch from MySQL to MariaDB

Preface

Over the years while working on various projects, I've often wished for a fully-featured web development environment confined to my local network. This would allow for offline development (before uploading to a public server), and also allow hosting of local projects that are never meant to be online.

This is an update of my previous LAMP setup guide, where we host a LAMP server in an UnRAID VM. Updated to use PHP 8 and replacing MySQL with (open source, drop-in replacement) MariaDB.

Large portions of this guide are unchanged from the previous version.

Note that I will refer to MariaDB as “MySQL” throughout, for consistency with traditional LAMP. MariaDB advertises substantial compatibility with MySQL, and all MySQL commands are aliased to the MariaDB executables.

Please Note: The choice of software and settings are entirely based on what I imagine my personal needs to be, and depend upon my current (possibly flawed) understanding of the software involved. This guide might not be suitable for you, and even if it is, it might contain errors. Proceed at your own discretion.

Content may be updated and expanded over time.... take note of the “Updated” date, above.

Overview

Operating system:

Linux Mint Xfce 21.2

Server:

Apache 2.4
MariaDB 10.11
PHP 8.2

Additional features:

phpMyAdmin 5.1
Samba network file sharing
Virtual hosts

* version numbers as of this writing

1. User accounts

Once you have completed all steps in this guide, a variety of accounts and users will exist.

Anywhere you see a VARIABLE in this document, substitute your chosen value. To change passwords later, refer to appendix A.

1.1 Linux Users

Linux Mint does not have a separate user named root. The first user you create during installation gets root privileges; in this guide the primary admin user is VMUSER.

`root`	`VMPASS`	Virtual root user; not a true account
`VMUSER`	`VMPASS`	Primary admin user; has root privileges; member of the `www-data` usergroup

1.2 SQL Users

`root`	`SQLPASS`	MySQL administrator; requires local superuser privileges to use
`SQLUSER`	`SQLPASS`	MySQL administrator; used to access phpMyAdmin
`DBUSER`	`DBPASS`	Limited user with permission to manage only the `DBNAME` database

You should create separate low-privilege users for accessing your databases from PHP projects, such as DBUSER, above; refer to phpMyAdmin user management, and section 8 of this guide.

1.3 Samba User

SMBUSER SMBPASS Used to connect to the network share \\mint-vm\www; member of the www-data usergroup

1.4 Linux Usergroups

www-data Any member of this group has full R/W access to web files, locally via /var/www or remotely via \\mint-vm\www

2. UnRAID VM setup

Download a long-term support (LTS) release of Linux Mint Xfce 64-bit
Place the ISO file in UnRAID /mnt/user/isos

UnRAID [VMs] tab → [Add VM] → [Linux]

Name: Linux Mint Xfce
Initial Memory: 8192 MB
Max Memory: 8192 MB
USB Controller: 3.0 (qemu XHCI)
OS Install ISO: [select downloaded ISO file]
Primary vDisk Size: 48G
[Create]

Launch [VNC Remote] from “Linux Mint Xfce” VM dropdown menu

3. Linux installation

From the boot menu, run [Start Linux Mint]
From the desktop, run [Install Linux Mint]
Accept all defaults, then [Install Now]

Your name: Administrator
Your computer's name: mint-vm
Pick a username: VMUSER
Choose a password: VMPASS
Confirm your password: VMPASS
Log in automatically: yes
[Continue]

Wait for installation, then [Restart Now]
“Please remove the installation medium then press enter” → just press enter
Wait for restart
Uncheck [Show this dialog at startup] on Welcome screen, then close it

Open [Update Manager] from the tray
[Edit] menu → [Preferences] → Notifications: set all values to 90 days
Close [Preferences] window
Install all available updates

Open [System Reports] from the tray (warning icon with exclamation mark)
[Ignore this report] for each detected issue

Open [Power Manager] from the tray (lightning bolt icon)
[Display] tab → uncheck [Display power management], set [Blank after] to never
[Security] tab → [Automatically lock the session] → [Never]

Start Menu → All Applications → [Settings Manager]
[Desktop] icon → [Icons] tab → Default Icons: ☑ Removable Devices

Start Menu → All Applications → [Synaptic Package Manager]
[Status] button → [Installed] → Uninstall packages by clicking the checkbox and selecting “Mark for complete removal”

celluloid
drawing
growisofs
hexchat
hexchat-common
hypnotix
libreoffice-common
libreoffice-*
mythes-*
pix
pix-data
rhythmbox
rhythmbox-data
thunderbird
transmission-common
uno-libs-private

[Apply] button → [Apply]

Start Menu → All Applications → [Session and Startup]
[Application Autostart] tab → Uncheck programs:

mintwelcome
PulseAudio Sound System
Update Manager

Start Menu → Power Icon → [Restart]

4. LAN configuration

These instructions apply to routers running Tomato firmware; tested on FreshTomato v2018.4

STATIC-IP is an IP address suitable for your LAN; ex: 192.168.0.55
HOSTNAME is a local hostname for your server; using an unassigned TLD such as .home or .lan is recommended (avoid .local as it is reserved for use with mDNS); ex: mint-vm.home

4.1 Set a static IP address

[Status] → [Device List] → (your VM) → [static]
Set a STATIC-IP address, [Add], [Save]

[Status] → [Device List] → (your VM) → (click on lease time to delete current lease)
Deleting the lease will expire the existing IP allocation

Reboot the Mint VM, then verify the static IP address is in use

4.2 Set a local hostname for the server

[Advanced] → [DHCP/DNS] → [Dnsmasq Custom Configuration]

local-ttl=1 address=/.HOSTNAME/STATIC-IP

[Save]

This allows any computer on your LAN to access the Mint VM via the host name HOSTNAME or any subdomain *.HOSTNAME

5. Install server software

Inside the Mint VM, open terminal and run these commands

5.1 Prepare to install AMP

sudo apt update && sudo apt -y upgrade sudo reboot

5.2 Install MariaDB SQL server

Find out what Ubuntu version your Mint OS is based on; we need the DISTRIB_CODENAME:

cat /etc/upstream-release/lsb-release

In my case, Linux Mint 21.2 is based on Ubuntu 22.04 “jammy”. The MariaDB respository only supports particular versions, so keep an eye on any error message generated from the CURL command below.

We want to install a long-term support (LTS) release of MariaDB. Check the releases list, note the newest “long-term MariaDB stable release” version number, MARIADB-VERSION. As of this writing, the latest LTS version is 10.11.

curl -LsS https://r.mariadb.com/downloads/mariadb_repo_setup | sudo bash -s -- --os-type=ubuntu --os-version=DISTRIB_CODENAME --mariadb-server-version="mariadb-MARIADB-VERSION" sudo apt-get install mariadb-server mariadb-client -y

mysql -V sudo service mariadb status | grep "Active:"

sudo mysql_secure_installation

Enter current password for root (enter for none): [press enter]
Switch to unix_socket authentication [Y/n]: N
Change the root password? [Y/n]: Y → SQLPASS → SQLPASS
Remove anonymous users? [Y/n]: Y
Disallow root login remotely? [Y/n]: Y
Remove test database and access to it? [Y/n]: Y
Reload privilege tables now? [Y/n]: Y

sudo nano /etc/mysql/mariadb.conf.d/50-server.cnf

Edit the line containing bind-address:

bind-address = 0.0.0.0

Ctrl+O, Enter (to save)
Ctrl+X (to exit nano)

sudo service mariadb restart

5.3 Install Apache web server

sudo apt-get install apache2 apache2-utils -y apache2 -v sudo service apache2 status | grep "Active:"

Test Apache: Open Firefox, view http://localhost

5.4 Install PHP and extensions

Add the ondrej repository for access to newer PHP versions, check available versions, then install PHP.

sudo add-apt-repository ppa:ondrej/php sudo apt-get update apt-cache policy php

sudo apt-get install php php-common php-cli libapache2-mod-php -y php -v

Install PHP extensions:

sudo apt-get install php-mysql php-mbstring php-curl php-xml php-intl php-gd php-imagick -y sudo service apache2 restart

Test PHP:

sudo nano /var/www/html/phpinfo.php

<?php phpinfo(); ?>

Ctrl+O, Enter (to save)
Ctrl+X (to exit nano)

Open Firefox, view http://localhost/phpinfo.php

5.5 Install phpMyAdmin and configure SQL user

sudo apt-get install phpmyadmin -y

when prompted for a webserver, press space to tick the box selecting apache2
when prompted to configure database, select yes
when prompted for MySQL password, enter SQLPASS

sudo mysql -uroot -pSQLPASS

DROP USER 'phpmyadmin'@'localhost'; CREATE USER 'SQLUSER'@'%' IDENTIFIED BY ''; GRANT ALL PRIVILEGES ON *.* TO 'SQLUSER'@'%' WITH GRANT OPTION; FLUSH PRIVILEGES; SELECT User,Host FROM mysql.user;

Ctrl+Z (to exit)

mysqladmin --user=SQLUSER password "SQLPASS"

sudo nano -w /etc/dbconfig-common/phpmyadmin.conf

Edit the line containing dbc_dbuser:

dbc_dbuser='SQLUSER'

Ctrl+O, Enter (to save)
Ctrl+X (to exit nano)

sudo nano -w /etc/phpmyadmin/config-db.php

Edit the line containing $dbuser:

$dbuser='SQLUSER';

Ctrl+O, Enter (to save)
Ctrl+X (to exit nano)

sudo service mysql restart sudo service apache2 restart

Open Firefox, view http://localhost/phpmyadmin
Username: SQLUSER
Password: SQLPASS

5.6 Enable “nologin” user accounts

sudo nano /etc/shells

Append this line to the end of the file:

/usr/sbin/nologin

Ctrl+O, Enter (to save)
Ctrl+X (to exit nano)

5.7 Set permissions on web folder

sudo adduser $USER www-data sudo chown $USER:www-data -R /var/www sudo chmod u=rwX,g=srwX,o=rX -R /var/www sudo chmod 0664 /var/www/html/*

5.8 Allow .htaccess configuration in web folder

sudo nano -w /etc/apache2/apache2.conf

Inside configuration block <Directory /var/www/>, alter the AllowOverride line:

AllowOverride All

Ctrl+O, Enter (to save)
Ctrl+X (to exit nano)

sudo service apache2 restart

5.9 Enable mod_rewrite Apache module

sudo a2enmod rewrite sudo service apache2 restart

5.10 Increase PHP upload and POST size limits

PHP defaults to 8 megabytes max POST size and 2 megabytes max file upload size. Changing these limits so they match can make debugging easier. Select a limit MAXUPLOAD megabytes that is suitable for your projects.

Note: the path below may require updating to match the installed PHP version.

sudo nano -w /etc/php/8.2/apache2/php.ini

Alter the line containing post_max_size:

post_max_size = MAXUPLOADM

Alter the line containing upload_max_filesize:

upload_max_filesize = MAXUPLOADM

Ctrl+O, Enter (to save)
Ctrl+X (to exit nano)

sudo service apache2 restart

5.11 Enable PHP error reporting

If you're using this server for development purposes, you will want to allow PHP to display errors. The display_errors setting should be On for development, and Off for production/live servers.

Note: the path below may require updating to match the installed PHP version.

sudo nano -w /etc/php/8.2/apache2/php.ini

Alter the line containing display_errors:

display_errors = On

Ctrl+O, Enter (to save)
Ctrl+X (to exit nano)

sudo service apache2 restart

Alternately, you can control this setting on a script-by-script basis by calling the PHP ini_set() function:

ini_set ('display_errors', 'On');

Error reporting can be further controlled by the error_reporting setting in php.ini or the corresponding error_reporting() function in your PHP script. For production I use a value of 0, or (E_ALL | E_STRICT) for development.

5.12 Clear command-line history and reboot

history -cw sudo reboot

6. Install and configure Samba

6.1 Install Samba

sudo apt-get update sudo apt-get install samba -y

6.2 Create Samba user

sudo useradd -s /usr/sbin/nologin SMBUSER sudo passwd SMBUSER

when prompted for password, enter SMBPASS

sudo adduser SMBUSER www-data

sudo smbpasswd -a SMBUSER

when prompted for password, enter SMBPASS

sudo smbpasswd -e SMBUSER

6.3 Add network share

sudo nano -w /etc/samba/smb.conf

Append these configuration lines to the end of the file:

[www] comment = Web Data path = /var/www guest ok = no read only = no writeable = yes browseable = yes valid users = +www-data create mask = 0664 directory mask = 0775

Ctrl+O, Enter (to save)
Ctrl+X (to exit nano)

sudo service smbd restart

Validate your Samba configuration:

testparm -s /etc/samba/smb.conf

normalized configuration file is printed; look for error messages

6.4 Test network share

On Windows you may need to flush all open network connections to use new credentials; run this from a command prompt:

net use * /delete

From a Windows PC, connect to the Samba share:
Start Menu → Run → "\\mint-vm\www"
Username: SMBUSER
Password: SMBPASS

7. Configure Apache virtual hosts

* Configuration tested on Apache v2.4

* For detailed reference, refer to the Apache documentation:

* Refer to section 4 in this guide to define a local hostname

Enable multi-project hosting using Apache virtual hosts; this example configures 4 hosts: delta, gamma, phpmyadmin, and a default host:

`delta.HOSTNAME`	`/var/www/delta`
`gamma.HOSTNAME`	`/var/www/gamma`
`phpmyadmin.HOSTNAME`	`/usr/share/phpmyadmin`
`HOSTNAME`	`/var/www/www`

Note that in this configuration the default host is served for any request by IP address and any request to an unknown hostname. This behaviour has security implications: if your server becomes publicly-accessible, your default host might be served. Therefore we remove all admin-related content (such as phpMyAdmin) from this area.

In this example we keep no content on the default host; all real content is served from specific subdomains.

7.1 Remove default host access to phpMyAdmin

Since phpMyAdmin will be accessed under its own subdomain, we should remove it from the default host; this allows us to explicitly control who can access it:

sudo nano -w /etc/phpmyadmin/apache.conf

Comment out (prepend a # character) this Alias line:

#Alias /phpmyadmin /usr/share/phpmyadmin

Ctrl+O, Enter (to save)
Ctrl+X (to exit nano)

sudo service apache2 restart

phpMyAdmin can no longer be accessed from http://localhost/phpmyadmin

7.2 Change the default host's server name and document root

By default Apache serves web files from /var/www/html; we change this directory to better integrate with a multi-host setup:

sudo nano -w /etc/apache2/sites-enabled/000-default.conf

Insert the following line at the top of the file:

ServerName HOSTNAME

This comment may be worth adding inside the <VirtualHost> configuration block:

# This first virtual host definition becomes the default. # Default is served for all requests not matching hosts below, # including requests by IP and requests for undefined hosts.

Add a ServerAlias line inside the <VirtualHost> configuration block:

ServerAlias www.HOSTNAME

Change the DocumentRoot line:

DocumentRoot "/var/www/www"

Ctrl+O, Enter (to save)
Ctrl+X (to exit nano)

Delete the previous html directory and create a new www directory
WARNING: all files in /var/www/html will be deleted!

rm -r /var/www/html mkdir /var/www/www

Validate your configuration and restart the server:

apache2ctl configtest sudo service apache2 restart

You may implement a website on the default host, however in this example setup we prefer to respond “404 Not Found” to all requests that don't match an expected virtual host subdomain:

nano /var/www/www/index.php

<?php http_response_code (404); header ('Content-Type: text/plain'); echo '404 Not Found'; die(); ?>

Ctrl+O, Enter (to save)
Ctrl+X (to exit nano)

Visiting any address that resolves to this server should now yield a 404 error, generated from /var/www/www/index.php; for example:

7.3 Reenable phpMyAdmin under a virtual host

sudo nano -w /etc/apache2/sites-enabled/000-default.conf

Append the following configuration block to the end of the file:

<VirtualHost *:80> DocumentRoot "/usr/share/phpmyadmin" ServerName phpmyadmin.HOSTNAME ServerAlias *.phpmyadmin.HOSTNAME </VirtualHost>

Ctrl+O, Enter (to save)
Ctrl+X (to exit nano)

Validate your configuration and restart the server:

apache2ctl configtest sudo service apache2 restart

Visiting http://phpmyadmin.HOSTNAME now accesses phpMyAdmin

7.4 Add additional virtual hosts, as desired

This example sets up two projects, delta and gamma, each with their own hostname and server directory. In your configuration, you would instead use these placeholders as examples to configure your own projects.

mkdir /var/www/delta mkdir /var/www/gamma

sudo nano -w /etc/apache2/sites-enabled/000-default.conf

Append the following configuration blocks to the end of the file:

<VirtualHost *:80> DocumentRoot "/var/www/delta" ServerName delta.HOSTNAME ServerAlias *.delta.HOSTNAME </VirtualHost> <VirtualHost *:80> DocumentRoot "/var/www/gamma" ServerName gamma.HOSTNAME ServerAlias *.gamma.HOSTNAME </VirtualHost>

Ctrl+O, Enter (to save)
Ctrl+X (to exit nano)

Validate your configuration and restart the server:

apache2ctl configtest sudo service apache2 restart

Access these sites via http://delta.HOSTNAME and http://gamma.HOSTNAME

8. Create a database and limited SQL user

Tip: Match the database name, username, and password of the database from your online hosting provider when configuring this local database. Migrating projects between the two then involves only changing the host name of the database server.

Execute this SQL code from the phpMyAdmin [SQL] tab to create a database:

CREATE DATABASE `DBNAME` CHARACTER SET utf8mb4 COLLATE utf8mb4_unicode_ci;

Create a limited user who can only control this database:

CREATE USER 'DBUSER'@'%' IDENTIFIED WITH mysql_native_password AS ''; GRANT USAGE ON *.* TO 'DBUSER'@'%' REQUIRE NONE; GRANT SELECT, INSERT, UPDATE, DELETE, CREATE, DROP, INDEX, ALTER, CREATE TEMPORARY TABLES, CREATE VIEW, EVENT, TRIGGER, SHOW VIEW, CREATE ROUTINE, ALTER ROUTINE, EXECUTE ON `DBNAME`.* TO 'DBUSER'@'%';

phpMyAdmin → [Home] → [User accounts] → (DBUSER) → [Edit privileges] → [Change password]
Assign a password DBPASS to the database user

From PHP, this database can now be accessed through mysqli or equivalent:

$db = new mysqli ('localhost', 'DBUSER', 'DBPASS', 'DBNAME');

Appendix A: Changing passwords

If you need to change an account password after initial setup, use the following procedures.

If you specify a password directly on the command-line, you can later clear the command-line history, for security:

history -cw

A.1 Linux User

sudo passwd VMUSER

sudo may ask for a password; use OLD-VMPASS
when prompted for new UNIX password, enter NEW-VMPASS

sudo reboot

A.2 SQL User

mysqladmin --user=SQLUSER --password=OLD-SQLPASS password "NEW-SQLPASS"

sudo nano -w /etc/dbconfig-common/phpmyadmin.conf

Edit the line containing dbc_dbpass:

dbc_dbpass='NEW-SQLPASS'

Ctrl+O, Enter (to save)
Ctrl+X (to exit nano)

sudo nano -w /etc/phpmyadmin/config-db.php

Edit the line containing $dbpass:

$dbpass='NEW-SQLPASS';

Ctrl+O, Enter (to save)
Ctrl+X (to exit nano)

sudo service mysql restart sudo service apache2 restart

A.3 Samba User

sudo passwd SMBUSER

sudo may ask for a password; use VMPASS
when prompted for new UNIX password, enter NEW-SMBPASS

sudo smbpasswd SMBUSER

when prompted for password, enter NEW-SMBPASS

sudo service smbd restart

On Windows you may need to flush all open network connections to use new credentials; run this from a command prompt:

net use * /delete

Appendix B: Mount a network share for read/write access

Mount a network share in Linux: This allows your VM to read from and write to shared folders on your network.

Appendix C: Project-specific features

Install the escpos-php receipt printer library

Install and test the escpos-php library: used for communicating with thermal receipt printers via the ESC/POS protocol.

Additionally, if your printer does not natively support printing QR codes, you can add image-based QR code support to the escpos-php library by integrating the PhpQrCode library.

Install the PHP Simple HTML DOM Parser

Install the SimpleHtmlDom library: This PHP library allows for exceptionally-easy web scraping and parsing of arbitrary HTML pages.

[end of guide]

IMagick image dithering for thermal receipt printers

Mon, 15 May 2023 03:15:11 GMT

Let's build a convenience function to load arbitrary image files and convert them to be suitable for thermal printing, using PHP libraries ImageMagick and escpos-php.

Until now I've been manually preparing images (such as the Magic 8-Ball) in Photoshop, resizing to fit the receipt printer resolution and then applying brightness adjustments and 1-bit dithering. This isn't particularly difficult, however it is an irreversible process which locks in a specific resolution and does take some fiddling. Much better to write some code to apply the necessary transformations on-demand.

Here's what we want to do to convert the original image into something printable:

Load the image from disk
Remove transparency and flatten layers onto a white background
Convert to greyscale
Optionally rotate the image (convenience feature)
If too wide, resize to fit receipt paper resolution
If too narrow, add padding depending on preferred left/center/right alignment
Brighten the image, to compensate for perceived darkness of printed images
Dither greyscale image into a 1-bit bitmap

(Click the images to see at full size; also ensure your browser isn't downscaling — dithered bitmaps have weird aliasing artifacts when scaled.)

PHP Code: LoadPrinterOptimizedImage

The function implementation is relatively straightforward, but note that it doesn't do any error-checking. (Bad programmer, no cookie!) We assume php-imagick and escpos-php are installed and available.

define ('PAPER_WIDTH_PIXELS',  384);
define ('PRINTER_IMAGE_GAMMA', 1.8);

function LoadPrinterOptimizedImage (string $filename,
                int $rotate = 0,
                int $align = Imagick::ALIGN_CENTER,
                float $gamma = PRINTER_IMAGE_GAMMA
                ) : ImagickEscposImage
{
    $imagick = new Imagick();
    $imagick->readImage ($filename);

    // Remove transparency, flatten layers onto a white background
    $imagick->setImageBackgroundColor ('white');
    $imagick->setImageAlphaChannel (Imagick::ALPHACHANNEL_REMOVE);
    $imagick->mergeImageLayers (Imagick::LAYERMETHOD_FLATTEN);

    // Convert to greyscale
    $imagick->transformImageColorspace (Imagick::COLORSPACE_GRAY);

    // Optionally rotate the image, constrain to 90 degree increments
    $rotate = 90 * ((int) round ($rotate / 90.0));
    if ($rotate)
    {
        $imagick->rotateImage ('white', $rotate);
        $imagick->setImagePage ($imagick->getImageWidth(), $imagick->getImageHeight(), 0, 0);
    }

    // Store image dimensions
    $imgWidth = $fileWidth = $imagick->getImageWidth();
    $imgHeight = $fileHeight = $imagick->getImageHeight();

    // Shrink image if too wide
    if ($fileWidth > PAPER_WIDTH_PIXELS)
    {
        $imgHeight = (int) round ((1.0 * $fileHeight * PAPER_WIDTH_PIXELS) / $fileWidth);
        $imgWidth = PAPER_WIDTH_PIXELS;
        $imagick->resizeImage ($imgWidth, $imgHeight, Imagick::FILTER_LANCZOS, 0.5);
        $imagick->setImagePage ($imgWidth, $imgHeight, 0, 0);
    }

    // Align image if too narrow
    else if ($fileWidth < PAPER_WIDTH_PIXELS)
    {
        switch ($align)
        {
            case Imagick::ALIGN_CENTER :
                $borderWidth = (int) ((PAPER_WIDTH_PIXELS - $fileWidth) / 2);
                break;

            case Imagick::ALIGN_RIGHT :
                $borderWidth = PAPER_WIDTH_PIXELS - $fileWidth;
                break;

            // Assume printer will left-align image by default
            default :
                $borderWidth = 0;
        }

        // Add a white border as an easy way to generate padding
        // Overflowing border pixels are cropped off, below
        if ($borderWidth > 0)
        {
            $imgWidth = $fileWidth + $borderWidth + $borderWidth;
            $imagick->borderImage ('white', $borderWidth, 0);
            $imagick->setImagePage ($imgWidth, $imgHeight, 0, 0);
        }
    }

    // Crop image to guarantee it doesn't exceed printable width
    $imgWidth = min ($imgWidth, PAPER_WIDTH_PIXELS);
    $imagick->cropImage ($imgWidth, $imgHeight, 0, 0);
    $imagick->setImagePage ($imgWidth, $imgHeight, 0, 0);

    // Apply gamma to brighten image while keeping black and white points
    $imagick->gammaImage ($gamma);

    // Dither! Use palette from built-in bitmap of alternating black/white pixels
    $palette = new Imagick();
    $palette->newPseudoImage (32, 32, 'pattern:GRAY50');
    $imagick->remapImage ($palette, Imagick::DITHERMETHOD_FLOYDSTEINBERG);

    // Dither! (doesn't look as nice as floyd-steinberg)
    //$imagick->quantizeImage (2, Imagick::COLORSPACE_GRAY, 0, true, false);

    // Threshold image at 50% (higher values means more goes to black)
    $imagick->thresholdImage (0.5 * $imagick->getQuantum());

    // Convert Imagick object to ImagickEscposImage
    $img = new ImagickEscposImage (null, false);
    $img->readImageFromImagick ($imagick);
    return ($img);
}

The resulting ImagickEscposImage object can be passed to the Printer::bitImage() function for printing.

Dithering Methods

There are a few ways to downsample a greyscale image into a dithered 1-bit image in ImageMagick. Using remapImage allows you to specify Floyd-Steinberg dithering, which has more pleasing results than some other methods.

An alternative method is to call quantizeImage, which produces adequate results in less code. It's unclear what dithering method is implemented here, but I prefer the results of remapImage.

ImageMagick also has various ways to perform an ordered dither, but the results are inferior for this use case.

Redundant Code

There is some unnecessary code in the function above. It's there since I can't be bothered to learn the detailed internal workings of PHP IMagick, and including it makes the code theoretically more robust, without hurting anything.

Calling setImagePage after each image manipulation is a means to ensure the virtual “canvas” of the image matches the actual dimensions of the image at each step. Likely unnecessary, but I'm unclear about what situations IMagick would allow these to become mismatched, so I leave it in.

Using thresholdImage is definitely not needed after the dither, but I like to call it on every bitmap before printing to ensure we're dealing with a purely black-and-white image. Doesn't hurt anything here, but feel free to delete.

Finally, I include some (int) casts and explicit floating point values in a few bits of math throughout. I truly have no idea what the type promotion rules are in a weakly-typed language like PHP, so I'm coding based on my knowledge of C, and just assuming PHP is similar. Probably some unnecessary casts and values in there, but no harm done.

Spock Module

Since Spock has been such a cooperative test subject during development, let's give him his own screaming.computer module.

function RunModule_spock (Printer $printer) : bool
{
    $printer->setEmphasis (true);
    $printer->text ("Spock\n");
    $printer->setEmphasis (false);

    $quotes = array (
        'Live long and prosper',
        'Peace, and long life',
        'Infinite diversity in infinite combinations',
        'Logic is the beginning of wisdom, not the end',
        'Challenge your preconceptions, or they will challenge you',
        'The needs of the many outweigh the needs of the few, or the one',
        'Once you have eliminated the impossible, whatever remains, however improbable, must be the truth',
        'Insufficient facts always invite danger',
        'I have been, and always shall be, your friend',
        'Humans smile with so little provocation',
        "My congratulations, Captain \u{2014} a dazzling display of logic",
        'Computers make excellent and efficient servants, but I have no wish to serve under them',
        'I will do whatever logically needs to be done',
        'Time is fluid... like a river with currents, eddies, backwash',
        'Change is the essential process of all existence',
        'Insults are effective only where emotion is present',
        'It is only logical'
        );

    $printer->setFont (Printer::FONT_B);
    $printer->text (mb_padstr (mb_wordwrap ("\u{201C}" . RandomElementFromArray ($quotes) . "\u{201D}", PAPER_WIDTH_FONTB_CHARS - 1), 1, 0) . "\n\n");
    $printer->setFont (Printer::FONT_A);

    $img = LoadPrinterOptimizedImage (__DIR__ . '/spock.png');
    $printer->bitImage ($img);

    return (true);
}

Nothing fancy here. Grab a random quote, align and wrap the text, resize and dither our image, then print it all out.

The mb_padstr function is new code I wrote to add left and right padding to each line of a wrapped string. Many receipt printers include ESC/POS functions to natively set left and right column limits for string output (which would achieve the same effect), but I find it easier to just manipulate the string in PHP and output normally.

You can see the effect of mb_padstr where both lines of the quote are left-indented by one space.

Bonus: One of the “Spock quotes” is not a Spock quote at all. Before you check that link, do you know which one?

I maintain that wise Mr. Spock was likely to have said this at some point as well, so it's acceptable to include here.

Purity Ring — Fineshrine

Tue, 02 Feb 2021 04:35:53 GMT

Best new (to me) song I've heard in months! Courtesy of Letterkenny.

Listen to it loud.
What a vibe!

Philosophical Nonsense Generator

Sat, 31 Oct 2020 18:38:05 GMT

Credit: This module is a direct adaptation of the New Age Bullshit Generator by Seb Pearce, using all his original text. His JavaScript code was ported to PHP by Mark Hazlewood, which I then refactored and largely rewrote.

As a module for the screaming.computer, I'm tentatively calling it the Philos-o-matic: Affirmational Platitude Generator.

Hogwash that looks compelling

Seb Pearce describes how the idea came while watching a particular pseudoscience-advocate involved in a philosophy debate:

The thing that really impressed me, though, was his command of the vocabulary of woo... This word is a blanket term for pseudoscience, New Age thinking, dubious alternative medicine and other things that reek of the heady fumes of snake oil. ...

As I sat there listening to the debates, I thought to myself, “This all sounds like random sequences of buzzwords. I bet I could write code to generate it.” It seemed like not only a fun side project, but a great way to prove how easy it is to make hogwash that looks compelling. It might help show that it's the language games and emotions that lure people into this stuff.

— On the New Age Bullshit Generator and parodying woo

The resulting script generates delightful pseudo-inspirational, pseudo-philosophical fragments of nonsense.

At a low level, the core code simply generates N sentences on a given topic from the available templates. My implementation follows a simple randomized structure:

Optional: 1 sentence on a random topic
Always: 3 sentences on a common topic
Optional: 1 or 2 sentences on separate topics

The sentences themselves are templated, with random words inserted according to type.

For example: "The goal of #fixedNP is to plant the seeds of #nMass rather than #nMassBad." can become “The goal of ultrasonic energy is to plant the seeds of self-actualization rather than dogma.”

This is all fairly straightforward random-text-generation stuff, but I have to give kudos to the high-quality templates written by Seb Pearce — the resulting text is highly readable and often charming.

Receipt printer word wrapping

On the receipt printer and screaming.computer side of things, I finally wrote a multibyte-safe word-wrapping function; important for blocks of text since the receipt printer is only 32 characters wide at FONT_A size.

(PHP has the wordwrap function, but it's no good for Unicode strings.)

My mb_wordwrap function inserts a Unicode soft break (U+2028) at all potential wrap points (surrounding all hard breaks, following runs of whitespace, following runs of dashes/hyphens). The string is then exploded at the soft breaks and each chunk is added to the current line if it will fit. When a line gets too long, a hard break is inserted, then we make a new line and carry on with the next chunk.

Compare the default hard-wrap at 32 characters with the intelligent word-wrap:

We are at a crossroads of life-f
orce and materialism. Bondage is
 born in the gap where passion h
as been excluded.

We are at a crossroads of life-
force and materialism. Bondage
is born in the gap where passion
has been excluded.

Again, this is all fairly trivial infrastructure code, but even ‘trivial’ code takes time to design and implement.

Unicode character mismapping

Some of the template strings contain curly-quotes, em-dashes, and other extended Unicode characters.

The escpos receipt printing library ostensibly handles the conversion from UTF-8 to the printer's various native codepages, however I've observed a few glitches where extended characters are printed incorrectly. (Often the right-single-quote U+2019 prints as an accented-lowercase-o for some reason).

A cursory glance at the Printer::text function leads to the EscposPrintBuffer::writeText function, which has some pretty inscrutable codepage-switching code.... I'll study this and debug it eventually, but not today.

In the meantime I yield to the code and simply replace the problematic characters with their nearest ASCII-equivalent.

Words to change your life

This concludes the initial implementation of module #3 for the screaming.computer! At this time, I feel it's important to recall the ancient wisdom:

It can be difficult to know
where to begin. Entity, look
within and empower yourself. How
should you navigate this non-
local solar system?

By evolving, we believe.

Say it with me: “By evolving, we believe!”

Dotter Dotter (projects archive)

Sat, 19 Sep 2020 03:36:21 GMT

Approximately one million years ago (on a previous blog circa 2008) I reblogged Dotter Dotter's 3D pixelcraft:

More retro inspiration: there's something about how the shading softens the hard pixel lines in Tibori Design's Dotter Dotter series that makes me almost lust for either a next-gen game done up with the renderer or — fire up your 3D printers — figure playsets of each. Nintendo's already essentially done the latter nearly spot on with their Super Mario Bros. dioramas, so it's up to somebody now to do the former.

— Offworld, via 4 color rebellion, via Chunnel.tv, December 2008

I'm quite fond of the Legend of Zelda series, and these Dotter Dotter renderings were particularly inspiring:

Coincidentally I'd recently been experimenting with 3D modelling and rendering using NewTek Lightwave (version 9!) and since I'm a sucker for any NES nostalgia, I was compelled to try my hand at recreating something in this vein.

As a superfan of the Metroid series, it was a natural choice to adapt a classic location:

Comparing the file-creation dates on all related source files, apparently I spent nearly eight weeks on this, though I never published the result. I remember lots of intense modelling sessions, and I wrote a bunch of custom code as a Lightwave plugin to assist with the pseudo-voxel modelling process. Everything was pumped through an ambient occlusion renderer module (running on a Pentium 4), then composited in layers.

Though I vaguely recall working on multiple scenes, this image is the only finalized render I have from this effort. I took some minimal artistic license with the block placement, but each cube face is pixel- and colour-accurate.

Behold, my 3D interpretation of NES Metroid:

MySQL Character Sets: utf8 is a Lie

Sun, 19 Jul 2020 20:38:44 GMT

So apparently everyone but myself knew that in MySQL, the utf8 character set is not true UTF-8, but a broken subset that supports only 3-byte characters. Also apparently utf8_general_ci is hopelessly defective and should never be used.

Hmmmph.

What you really want is utf8mb4 and utf8mb4_unicode_ci. This gives you true UTF-8 support and standards-compliant sorting.

Spent part of an afternoon updating all my code and converting my databases to support the correct charset. Should be good-to-go now.

Also updated the database-creation code in my LAMP Server Setup Guide.

One Year of Screaming

Fri, 10 Jul 2020 15:31:13 GMT

This week marks one year since the inspiration for the screaming.computer project first came to me.

I've made gradual progress, working in fits and starts, and taking plenty of detours along the way. This is my ideal mode of development. Even the project goals remain intentionally underdeveloped, which is a clever way for me to shoehorn any interest-of-the-moment under the screaming.computer banner. Not sure why I find this helpful, but I do.

I do have plans, though, and an awesomely-odd end result in mind. It may take a while to get there, but I'm thoroughly enjoying the journey. As I mentioned in the first post here, this has been a platform to exercise my creativity and tickle the odd recesses of my brain. What more could I ask for?!

Here's to another year of screaming.

Cheers!

Amazing Mazes of Varying Difficulty

Sun, 14 Jun 2020 05:25:54 GMT

Module number two for the screaming.computer is a Maze Generator!

After much research into maze generation algorithms, I realized it was fascinating, but a deeper rabbit-hole than I wanted to explore at the moment. Thankfully there are plenty of pre-written maze generators available online, ready to use with some minor tweaks.

I grabbed Bill Parrott's PHP maze class since it seemed pretty straightforward. It generates random mazes of arbitrary size, but unfortunately only renders them to an HTML-based text format.

I modified the display algorithm to instead generate a PNG image via ImageMagick (as in the example image here), and expanded the code to allow for arbitrary cell size.

Once the image generation was in place, I needed to adapt it to the constraints of my thermal receipt printer. Finished off a roll of paper during the dev process; thankfully I bought a big multipack of supplies.

The major issue that immediately presented itself was the printer failed to print the top and bottom borders of the maze image. As far as I can tell, the printer just can't handle a solid horizontal line. I tried increasing the line thickness, but to no avail. Something about the thermal printing process responds poorly to large streaks of pure black (I saw this with the dithered Magic 8-Ball image as well).

The solution I came up with was to rotate the image, thereby causing perfectly-horizontal lines to break up over multiple rows. I experimented with various degrees of rotation; 30° and 45° rotations looked most visually pleasing, but the necessary reduction in size was too much for my taste. I settled on a counterclockwise 1° rotation. It looks a little crooked, but serves the purpose of fixing the horizontal line printing issue.

Various stages of development and testing can be seen here:

The code was then integrated into my standardized module interface. This means when the screaming.computer is run, a module is randomly selected and executed. So far I have just two: the 8-Ball and this Maze.

Maze Difficulty

In the spirit of variety, I randomly select a cell size and maze height (within sensible constraints given the printer resolution). The smaller the cell the more “difficult” the maze is considered to be. Mix in some fun strings to describe the difficulties, and boom, we're done:

$randDifficulty = random_int (0, 1000) / 1000.0; $cellSize = (int) round (($maxCellSize - $minCellSize) * (1.0 - $randDifficulty)) + $minCellSize; $difficulties = array ('Trivial', 'No sweat', 'Easy-peasy', 'Pretty easy', 'Not so hard', 'Make you think', 'Extra medium', 'Time consuming', 'Challenging', 'Expert', 'Painful', 'Hurt me'); $difficultyStr = mb_strtoupper ($difficulties[(int) round ($randDifficulty * (count ($difficulties) - 1))]);

It's a-maze-ing!

It is decidedly so

Thu, 30 Apr 2020 23:27:38 GMT

The screaming.computer has its first module: The Magic 8-Ball. Not exactly a poetry-generator, but it's got to start somewhere!

Infrastructure is in place to randomly load and execute any available module (although just this one exists at the moment), optionally with weighted probability of selection, to account for some modules having more or less variety of output.

The Magic 8-Ball seemed like a straightforward proof-of-concept. Perhaps next I'll do a fortune cookie.... Development on the complex stuff like poetry-generation continues in the background, but it's nice to be able to quickly integrate these simpler ideas as they pop into my head.

Mount a Network Share in Linux

Thu, 26 Mar 2020 15:21:47 GMT

To access a shared folder on your network from Linux Mint, it must be mounted to the local Linux filesystem. Getting the read/write permissions correct is a bit tricky, and often glossed over in other tutorials.

This guide, as usual, assumes your system is configured per the LAMP server setup guide. Furthermore, I assume your network share is wide open (permitting anonymous access) and you want to allow full read/write access from Linux. If your use-case is different, you'll need to adjust the mount parameters.

Since I want to access this share from PHP and Apache, I will be setting its group to the www-data usergroup and enabling group read/write permissions.

Create a directory for your mount point

Create a directory, then set owner and permissions:

sudo mkdir /media/my-network-share sudo chown $USER:www-data -R /media/my-network-share sudo chmod 02775 /media/my-network-share

Mount a network share from terminal

Mount the folder using the mount command (all one line, no spaces after commas):

sudo mount -t cifs -o username=$USER,password=,uid=$(id -u),gid=$(id -g www-data),file_mode=0664,dir_mode=02775 //SHARE-IP/SHARE-PATH /media/my-network-share/

SHARE-IP is the IP address of the system which has the shared folder. (You should also be able to use its name, however on my system the name wouldn't resolve and rather than fixing that issue I just used the IP instead.) SHARE-PATH is the shared folder name or path.

The uid and gid parameters mean the mounted directory will be owned by you (the current Linux user) and the www-data Linux usergroup.

The file_mode and dir_mode parameters set the permissions on the mounted directory so that both owner and group can read and write.

This network share will remain mounted until the next reboot. See below for persistent mounts.

Unmount all shares

sudo umount -a -t cifs -l

Auto-mount a network share on every boot

To have the network share automatically mounted on every boot, add it to the fstab file. This requires slightly different syntax, and you must manually determine your user and group ID numbers in advance.

Find your USERID number:

id -u

Find the GROUPID number for the www-data usergroup:

id -g www-data

Use nano to append a line to the fstab file (all one line, no spaces after commas):

sudo nano -w /etc/fstab

//SHARE-IP/SHARE-PATH /media/my-network-share cifs username=USERNAME,password=,uid=USERID,gid=GROUPID,file_mode=0664,dir_mode=02775

Ctrl+O, Enter (to save)
Ctrl+X (to exit nano)

To immediately mount via the fstab file, run:

sudo mount -a

To ensure everything works as expected, reboot your system, then check the share:

sudo reboot ls -l /media/my-network-share/

Scraping the News

Tue, 17 Mar 2020 21:44:35 GMT

Over the past five weeks I've been busy working on a web scraper to gather daily news content from the web. The scraper has been running for about a month, and has so far collected over 10,000 unique articles. It continues to run, gathering new content in realtime.

Scraper activity summary

Source	Total indexed URLs	Total parsed URLs	Daily scraped URLs (7-day average)
News Site A	2899	2668	105
News Site B	3202	2904	99
News Site C	5617	4649	206
Total	11718	10221	410

At this time the article text is simply being stored in a database along with some minimal metadata (date of publication, etc.). The eventual goal is to use this text as source material for the screaming.computer's generative algorithms. There is also great potential to run various statistical analyses on the text. All of that is still to come.

Scraping process

Never having written a web scraper before, I stuck to a straightforward approach using PHP and the Simple HTML DOM Parser library. The resulting indexer/scraper is only as sophisticated as it needs to be to get the job done. It follows a three-stage process:

Indexing
Gather links to potential news articles from a news site's main page.
Scraping
Screen out unwanted links; download the page; verify it conforms to article format.
Parsing
Parse the article page; strip out unwanted content (related links sections, pullquotes, embedded multimedia, etc.); reduce to plain text; store headline, publication date, and article text in database.

All this is scheduled using cron jobs.

There is a bunch of logic to filter out duplicate articles (news sites love to provide the same content under multiple headlines and URLs). The code to normalize the article text (weeding out unwanted bits of the web page) is customized for each site. This custom code is necessarily brittle and threatens to break at any moment, but such is the nature of web scraping!

Next steps

The indexer/scraper/parser framework is robust enough that I can add additional news sources in the future if desired. Each new source takes a few days to customize, including many rounds of reviewing and correcting the results to handle edge-cases.

With the current sources combined, I'm getting about 350 successfully-parsed articles per day. This should be sufficient to move on to the next stage of the project: breaking the articles into component parts and performing basic text analysis.

Saturday Night Coding Fuel

Sun, 01 Mar 2020 01:47:32 GMT

YouTube randomly suggested this live DJ set by Belgium-based Amelie Lens, and it makes the perfect background for some weekend evening coding.

Been a while since I've listened to some proper techno.

As one commenter put it, “come for the music, stay for the cat.”

Install the PHP Simple HTML DOM Parser for easy web scraping

Mon, 17 Feb 2020 01:38:07 GMT

When brainstorming for this project, I knew I'd eventually need to write a web scraper to gather text content for the screaming.computer. I did quite a bit of Googling, and none of the scraping options looked promising. The available PHP libraries tended to be wildly overcomplicated for my needs, or very out-of-date, or just unnecessarily difficult to use. There were also a bunch of cloud-based scrapers and a few browser plugins, but these have dependencies I'd rather avoid.

Discovering the PHP Simple HTML DOM Parser library was like striking gold. It's up-to-date, easy-to-use, and still quite fully-featured.

Install SimpleHtmlDom using composer

Having previously installed composer to manage another library, it's already available on my LAMP server.

Create a directory for the SimpleHtmlDom library:

mkdir /var/www/_simplehtmldom cd /var/www/_simplehtmldom

Attempt to install the library stable version:

composer require simplehtmldom/simplehtmldom

Could not find a version of package simplehtmldom/simplehtmldom matching your minimum-stability (stable).

Attempt to install any available version of the library:

composer require simplehtmldom/simplehtmldom:*

Your requirements could not be resolved to an installable set of packages. The requested package simplehtmldom/simplehtmldom * is satisfiable by simplehtmldom/simplehtmldom[2.0-RC2, dev-master] but these conflict with your requirements or minimum-stability.

Okay, fine, we'll install the Release Candidate by name:

composer require simplehtmldom/simplehtmldom:2.0-RC2

Clearly I don't know anything about how to use composer, but we have success nonetheless!

Scrape the web using PHP

This PHP fragment shows one basic use of SimpleHtmlDom — loading the CBC website and printing a list of all links on the page:

require_once ('/var/www/_simplehtmldom/vendor/autoload.php'); use simplehtmldom\HtmlWeb; $webParser = new HtmlWeb(); $htmlDoc = $webParser->load ('https://www.cbc.ca/news/'); foreach ($htmlDoc->find ('a') as $anchor) echo $anchor->href, '<br>';

There are also some very helpful examples at the SimpleHtmlDom site.

Add image-based QR code support to escpos-php

Sun, 16 Feb 2020 01:31:20 GMT

The thermal receipt printer I am currently using doesn't natively supporting printing QR codes.

We can extend the escpos-php library to add image-based QR code support through the PhpQrCode library, as indicated in this tutorial by mike42 (the author of escpos-php).

These instructions assume a LAMP server with escpos-php has been configured per previous guides.

Install GD and PhpQrCode

Install the GD graphics library for PHP (verify your PHP version, alter GD library name as appropriate)

php --version sudo apt-get install php7.2-gd sudo service apache2 restart

Download the PhpQrCode library
Unzip it into /var/www/_phpqrcode

Subclass the escpos-php Printer class

We can create a new QrImgPrinter class which extends the escpos-php Printer class, but implements the qrCode function using image-based techniques rather than native printer support.

This code is based on the mike42 tutorial, but is updated to fix a few bugs and work with the current versions of PhpQrCode and escpos-php.

Create a new PHP file /var/www/_escpos/QrImgPrinter.php:

<?php require_once ('/var/www/_escpos/vendor/autoload.php'); use Mike42\Escpos\Printer; use Mike42\Escpos\EscposImage; require_once ('/var/www/_phpqrcode/qrlib.php'); class QrImgPrinter extends Printer { function qrCode (string $content, int $ec = self::QR_ECLEVEL_L, int $size = 3, int $model = self::QR_MODEL_2) { // Validate inputs self::validateInteger ($ec, 0, 3, __FUNCTION__); self::validateInteger ($size, 1, 16, __FUNCTION__); self::validateInteger ($model, 1, 3, __FUNCTION__); if (strlen ($content) < 1) return; // Only Model 2 supported in phpqrcode $model = self::QR_MODEL_2; // Generate filename for temp file $tmpfname = tempnam (sys_get_temp_dir(), 'escpos-php'); // Create QR code in temp file and print it QRcode::png ($content, $tmpfname, $ec, $size, 0, false); $img = EscposImage::load ($tmpfname, false); $this->bitImage ($img); // Delete temp file unlink ($tmpfname); } } ?>

Use the QrImgPrinter class to print QR codes

In your existing receipt printing code, include the QrImgPrinter.php file and change your class instantiation from new Printer to new QrImgPrinter. Then call the qrCode member function normally to print a QR code as an image:

$connector = new FilePrintConnector ('php://stdout'); $printer = new QrImgPrinter ($connector); $printer->initialize(); $printer->qrCode ('http://screaming.computer', Printer::QR_ECLEVEL_L, 6); $printer->text ("\n"); // Flush $printer->close();

Install and test the escpos-php library

Tue, 11 Feb 2020 03:41:13 GMT

Most thermal receipt printers are controlled using the ESC/POS protocol. This is a standard set of control codes to control font size and style, print images and barcodes, etc. (though not all printers support all features — some testing is generally required). The escpos-php library is a fantastic piece of software which wraps this protocol in an easy-to-use set of PHP classes.

Installing the escpos-php library is fairly easy, however it uses the composer dependency manager which I was previously unfamiliar with.

These are the steps I took to install escpos-php on my Linux server VM and print using my thermal receipt printer:

Install composer:

sudo apt install composer

Install the php-intl module:

sudo apt-get install php-intl sudo service apache2 restart

Create a folder for escpos-php in your web directory, then install it:

mkdir /var/www/_escpos cd /var/www/_escpos composer require mike42/escpos-php

Create a PHP file printerTest.php in a suitable location:

require_once ('/var/www/_escpos/vendor/autoload.php'); use Mike42\Escpos\Printer; use Mike42\Escpos\PrintConnectors\FilePrintConnector; $connector = new FilePrintConnector ('php://stdout'); $printer = new Printer ($connector); $printer->initialize(); $printer->text ("test\n"); $printer->close();

This PHP file will output the binary control codes to stdout. We run the program and pipe the output to our printer as follows:

php printerTest.php | lp -s -d THERMALPRINTER

In theory, we could use a CupsPrintConnector instead of the FilePrintConnector which would save us the step of redirecting the output. However, in my (very brief) test, the output seems to go into a print queue and must be manually released before it will print. This may have been a one-time hiccup or there may be a workaround, but using the FilePrintConnector avoided the issue and suits my needs for now.

[SOLVED] Connect a thermal receipt printer to a Linux VM in UnRAID

Sat, 08 Feb 2020 03:08:45 GMT

Guide v1.6 / Updated 2020-02-08 / First published 2020-02-07 / echo (at) screaming (dot) computer

I experienced many problems trying to access my thermal printer from my Linux VM running in UnRAID. After many diagnostics and lots of troubleshooting, I identified a two-part solution:

Install a USB expansion card into the UnRAID server and pass it through for the exclusive use of the VM. This addresses low-level USB errors in the virtual machine.
Install a generic CUPS driver and use the lp command to send data to the printer. This addresses the issue where usblp won't mount the device.

POS58 thermal receipt printer

This particular thermal printer is listed as:

Manufacturer=GD32 Microelectronics
Product=POS58 USB Printer
USB device: Winbond Electronics Corp. Virtual Com Port
Vendor & Product ID: 0416:5011

It's sold under the name “58MM USB Thermal Receipt Printer, Symcode” on Amazon.ca.

USB diagnostics in Linux

Some miscellaneous Linux commands which are helpful for diagnosing USB-connected devices:

lsusb lsusb -v ls -l /dev/usb usb-devices lspci | grep USB dmesg

Failure part 1: libusb errors in UnRAID VM

With the thermal printer plugged into the UnRAID system (prior to adding the USB expansion card) and passed through to the VM, the VM system log showed the following errors when booting:

libusb: error [op_set_interface] setintf failed error -1 errno 110 libusb: error [op_clear_halt] clear_halt failed error -1 errno 71

Under lsusb it appeared as a Winbond Electronics Corp. Virtual Com Port, and running usb-devices showed the device as a POS58 USB Printer.

The printer appeared to be mounted correctly by the usblp kernel module at /dev/usb/lp0.

Inital attempts to access the printer failed due to lack of user permissions. The lp0 device was part of the lp usergroup, so I added my current user to that group:

sudo usermod -a -G lp $USER sudo reboot

Even with correct permissions, sending data to the printer always failed with I/O errors:

echo "test" >> /dev/usb/lp0

bash: echo: write error: Input/output error

...and the VM system log showed this error:

libusb: error [submit_bulk_transfer] submiturb failed error -1 errno=2

Solution part 1: Add a USB expansion card dedicated for VM use

Install your USB expansion card and boot your UnRAID server.

UnRAID [Tools] tab → [System Devices]

Find the PCI ID of your newly-installed card and save it for later use; it is in the form XXXX:XXXX, where the X's are hexadecimal digits. My expansion card appeared as:

IOMMU group 13: [1106:3483] 03:00.0 USB controller: VIA Technologies, Inc. VL805 USB 3.0 Host Controller (rev 01)

so the ID number is 1106:3483

WARNING: Do not get this ID number wrong. Be sure you have the ID of the correct device. Using the wrong ID in the following steps can cause serious issues for UnRAID. Editing the following settings can cause your UnRAID server to become unbootable. Proceed at your own discretion.

UnRAID [Main] tab → [Flash] device → [Syslinux Configuration] → click in the [unRAID OS] textbox

On the append line, add a vfio-pci.ids parameter with the ID of your USB expansion card; this causes UnRAID to avoid “claiming” this device on startup, allowing it to be passed through for the exclusive use of a VM.

After editing, my append line in the unRAID OS section looked as follows:

append initrd=/bzroot vfio-pci.ids=1106:3483

[Apply], [Reboot] your UnRAID server

UnRAID [VMs] tab → (your VM) → [Edit]

USB Controller: 3.0 (qemu XHCI)
Other PCI Devices: [check the box for your expansion card]
[Update]

If you had previous USB devices passed-through to the VM which are no longer connected, you may receive this error: “internal error: unknown pci source type 'vendor'” — The easiest way to resolve this is to reconnect the USB devices, deselect them in the VM configuration, then remove the devices.

UnRAID [VMs] tab → (your VM) → [Start]
UnRAID [VMs] tab → (your VM) → [Logs]

Watch the log window for errors. Mine booted without issue.

Using VNC to access the VM, open a terminal. Run lsusb to observe your USB expansion card.

Successfully resolved: boot-time libusb errors. USB ports are now functioning correctly.

Failure part 2: usblp fails to mount the thermal printer device

Plug the thermal printer into the USB expansion card, run ls /dev/usb to see the mounted device (expecting lp0 or similar), then test the device while watching the log:

echo "test" >> /dev/usb/lp0

If your printer prints the word “test,” congratulations, it works!

Unfortunately this was unsuccessful for me. Running ls /dev/usb came up empty. Curiously, usblp was not mounting the printer now even though it did so prior to using the expansion card.

Running dmesg revealed the following error:

usblp: can't set desired altsetting 0 on interface 0

My expansion card appeared to be successfully configured, but this particular model of USB printer seems to behave in quirky or non-standards-compliant ways.

Others have observed similar issues with this model of printer:

It appears that usblp is failing to initialize and mount the printer.

(If, in your case, you see the device is mounted but it still generates I/O errors, look into blacklisting usblp and try the CUPS solution, below.)

Solution part 2: Install CUPS driver, use lp command to print

* Solution found in this AskUbuntu post: Print via terminal without usblp.

In the Linux Mint GUI, open [Start Menu] → [System] → [Printers] → [+Add]

In the list of [Devices] there was an entry for “Unknown (Printer),” described as “A printer connected to a USB port.” This was the thermal printer.

Devices: Unknown (Printer)
[Forward]

Select printer from database: yes
Makes: Generic
[Forward]

Models: Raw Queue
[Forward]

Printer Name: THERMALPRINTER
[Apply]

Open terminal, test the printer:

echo "test" | lp -d THERMALPRINTER

The printer successfully printed “test” for me.

You can suppress the job ID messages on stdout using the -s option. See the lp man page for full lp command syntax.

Successfully resolved: Use a generic CUPS driver to access the USB printer, in situations where usblp fails to mount the device.

Set up a LAMP server VM in UnRAID

Tue, 21 Jan 2020 23:35:00 GMT

Guide v5.12 / Updated 2020-07-19 / First published 2020-01-21 / echo (at) screaming (dot) computer

This guide has been superceded by an updated version: [Updated 2023-09] LAMP server VM in UnRAID setup guide.
New in that version: LTS release of Linux Mint; upgrade to PHP 8; switch from MySQL to MariaDB

Preface

After a few unsatisfactory experiments with running a WAMP stack on my laptop, I decided to dive in and configure a proper LAMP server on a Linux virtual machine. This approach was ideal since I already had a home server running UnRAID, which has great VM support.

This guide was written primarily for myself as I set up the VM and configured Linux, and installed/configured all the various features and settings that are important for my needs. There was a lot of trial-and-error to get everything working, so I wanted to ensure the “correct” procedures were captured somewhere. The guide grew to the point where it seemed sensible to share publicly in the hopes that others might find it helpful. Here it is.

Please Note: The choice of software and settings are entirely based on what I imagine my personal needs to be, and depend upon my current (possibly flawed) understanding of the software involved. This guide might not be suitable for you, and even if it is, it might contain errors. Proceed at your own discretion.

Content may be updated and expanded over time... take note of the “Updated” date, above.

Overview

Platform:

Linux Mint Xfce 19.3

Server:

Apache 2.4
MySQL 5
PHP 7.2

Additional features:

phpMyAdmin 4.6
ImageMagick 6.9 PHP plugin
Samba network file sharing
Virtual hosts

* version numbers as of this writing

1. User accounts

Once you have completed all steps in this guide, a variety of accounts and users will exist.

Anywhere you see a VARIABLE in this document, substitute your chosen value. To change passwords later, refer to appendix A.

1.1 Linux Users

Linux Mint does not have a separate user named root. The first user you create during installation gets root privileges; in this guide the primary admin user is VMUSER.

`root`	`VMPASS`	Virtual root user; not a true account
`VMUSER`	`VMPASS`	Primary admin user; has root privileges; member of the `www-data` usergroup

1.2 SQL Users

`root`	`SQLPASS`	MySQL administrator; requires local superuser privileges to use
`SQLUSER`	`SQLPASS`	MySQL administrator; used to access phpMyAdmin
`DBUSER`	`DBPASS`	Limited user with permission to manage only the `DBNAME` database

You should create separate low-privilege users for accessing your databases from PHP projects, such as DBUSER, above; refer to phpMyAdmin user management, and section 8 of this guide.

1.3 Samba User

SMBUSER SMBPASS Used to connect to the network share \\mint-vm\www; member of the www-data usergroup

1.4 Linux Usergroups

www-data Any member of this group has full R/W access to web files, locally via /var/www or remotely via \\mint-vm\www

2. UnRAID VM setup

Download Mint Xfce 64-bit ISO from https://www.linuxmint.com/download.php
Place the ISO file in UnRAID /mnt/user/isos

UnRAID [VMs] tab → [Add VM] → [Linux]

Name: Linux Mint Xfce
Initial Memory: 1024 MB
Max Memory: 1024 MB
OS Install ISO: [select downloaded ISO file]
Primary vDisk Size: 16G
[Create]

Launch [VNC Remote] from “Linux Mint Xfce” VM dropdown menu

3. Linux installation

From the boot menu, run [Start Linux Mint]
From the desktop, run [Install Linux Mint]
Accept all defaults, then [Install Now]

Your name: Administrator
Your computer's name: mint-vm
Pick a username: VMUSER
Choose a password: VMPASS
Confirm your password: VMPASS
Log in automatically: yes
[Continue]

Open [Update Manager] from the tray
Install all available updates

Open [System Reports] from the tray (warning icon with exclamation mark)
[Ignore this problem] for each detected issue

4. LAN configuration

These instructions apply to routers running Tomato firmware; tested on FreshTomato v2018.4

4.1 Set a static IP address

[Status] → [Device List] → (your VM) → [static]
Set a STATIC-IP address, [Add], [Save]

[Status] → [Device List] → (your VM) → (click on lease time to delete current lease)
Deleting the lease will expire the existing IP allocation

Reboot the Mint VM, then verify the static IP address is in use

4.2 Set a local hostname for the server

[Advanced] → [DHCP/DNS] → [Dnsmasq Custom Configuration]

local-ttl=1 address=/.HOSTNAME/STATIC-IP

[Save]

This allows any computer on your LAN to access the Mint VM via the host name HOSTNAME or any subdomain *.HOSTNAME

5. Install server software

Inside the Mint VM, open terminal and run these commands

5.1 Install LAMP

sudo apt-get update && sudo apt-get dist-upgrade -y sudo reboot sudo apt-get install lamp-server^ -y

Test Apache: Open Firefox, view http://localhost

5.2 Test PHP

sudo nano /var/www/html/phpinfo.php

<?php phpinfo(); ?>

Ctrl+O, Enter (to save)
Ctrl+X (to exit nano)

sudo service apache2 restart

Open Firefox, view http://localhost/phpinfo.php

5.3 Install phpMyAdmin and configure SQL user

sudo apt-get install phpmyadmin -y

when prompted for a webserver, press space to tick the box selecting apache2
when prompted to configure database, select yes
when prompted for MySQL password, enter SQLPASS

sudo mysql -uroot -pSQLPASS

DROP USER 'root'@'localhost'; DROP USER 'phpmyadmin'@'localhost'; CREATE USER 'SQLUSER'@'%' IDENTIFIED BY ''; GRANT ALL PRIVILEGES ON *.* TO 'SQLUSER'@'%' WITH GRANT OPTION; FLUSH PRIVILEGES; SELECT User,Host FROM mysql.user;

Ctrl+Z (to exit)

mysqladmin --user=SQLUSER password "SQLPASS"

sudo nano -w /etc/dbconfig-common/phpmyadmin.conf

Edit the line containing dbc_dbuser:

dbc_dbuser='SQLUSER'

Ctrl+O, Enter (to save)
Ctrl+X (to exit nano)

sudo nano -w /etc/phpmyadmin/config-db.php

Edit the line containing $dbuser:

$dbuser='SQLUSER';

Ctrl+O, Enter (to save)
Ctrl+X (to exit nano)

sudo service mysql restart sudo service apache2 restart

Open Firefox, view http://localhost/phpmyadmin
Username: SQLUSER
Password: SQLPASS

5.4 Enable “nologin” user accounts

sudo nano /etc/shells

Append this line to the end of the file (no trailing newline):

/usr/sbin/nologin

Ctrl+O, Enter (to save)
Ctrl+X (to exit nano)

5.5 Set permissions on web folder

sudo adduser $USER www-data sudo chown $USER:www-data -R /var/www sudo chmod u=rwX,g=srwX,o=rX -R /var/www sudo chmod 0664 /var/www/html/*

5.6 Allow .htaccess configuration in web folder

sudo nano -w /etc/apache2/apache2.conf

Inside configuration block <Directory /var/www/>, alter the AllowOverride line:

AllowOverride All

Ctrl+O, Enter (to save)
Ctrl+X (to exit nano)

sudo service apache2 restart

5.7 Enable mod_rewrite Apache module

sudo a2enmod rewrite sudo service apache2 restart

5.8 Install ImageMagick plugin for PHP

sudo apt-get install php-imagick sudo service apache2 restart

5.9 Increase PHP upload and POST size limits

Note: the path below may require updating to match the installed PHP version.

sudo nano -w /etc/php/7.2/apache2/php.ini

Alter the line containing post_max_size:

post_max_size = MAXUPLOADM

Alter the line containing upload_max_filesize:

upload_max_filesize = MAXUPLOADM

Ctrl+O, Enter (to save)
Ctrl+X (to exit nano)

sudo service apache2 restart

5.10 Enable PHP error reporting

If you're using this server for development purposes, you will want to allow PHP to display errors. The display_errors setting should be On for development, and Off for production/live servers.

Note: the path below may require updating to match the installed PHP version.

sudo nano -w /etc/php/7.2/apache2/php.ini

Alter the line containing display_errors:

display_errors = On

Ctrl+O, Enter (to save)
Ctrl+X (to exit nano)

sudo service apache2 restart

Alternately, you can control this setting on a script-by-script basis by calling the PHP ini_set() function:

ini_set ('display_errors', 'On');

5.11 Reboot

sudo reboot

6. Install and configure Samba

6.1 Install Samba

sudo apt-get update sudo apt-get install samba

6.2 Create Samba user

sudo useradd -s /usr/sbin/nologin SMBUSER sudo passwd SMBUSER

when prompted for password, enter SMBPASS

sudo adduser SMBUSER www-data

sudo smbpasswd -a SMBUSER

when prompted for password, enter SMBPASS

sudo smbpasswd -e SMBUSER

6.3 Add network share

sudo nano -w /etc/samba/smb.conf

Append these configuration lines to the end of the file:

[www] comment = Web Data path = /var/www guest ok = no read only = no writeable = yes browseable = yes valid users = +www-data create mask = 0664 directory mask = 0775

Ctrl+O, Enter (to save)
Ctrl+X (to exit nano)

sudo service smbd restart

Validate your Samba configuration:

testparm -s /etc/samba/smb.conf

normalized configuration file is printed; look for error messages

6.4 Test network share

Validate your network share:

smbtree

look for \\MINT-VM\www

From a Windows PC, connect to the Samba share:
Start Menu → Run → "\\mint-vm\www"
Username: SMBUSER
Password: SMBPASS

7. Configure Apache virtual hosts

* Configuration tested on Apache v2.4

* For detailed reference, refer to the Apache documentation:

* Refer to section 4 in this guide to define a local hostname

Enable multi-project hosting using Apache virtual hosts; this example configures 4 hosts: delta, gamma, phpmyadmin, and a default host:

`delta.HOSTNAME`	`/var/www/delta`
`gamma.HOSTNAME`	`/var/www/gamma`
`phpmyadmin.HOSTNAME`	`/usr/share/phpmyadmin`
`HOSTNAME`	`/var/www/www`

In this example we keep no content on the default host; all real content is served from specific subdomains.

7.1 Remove default host access to phpMyAdmin

Since phpMyAdmin will be accessed under its own subdomain, we should remove it from the default host; this allows us to explicitly control who can access it:

sudo nano -w /etc/phpmyadmin/apache.conf

Comment out (prepend a # character) this Alias line:

#Alias /phpmyadmin /usr/share/phpmyadmin

Ctrl+O, Enter (to save)
Ctrl+X (to exit nano)

sudo service apache2 restart

phpMyAdmin can no longer be accessed from http://localhost/phpmyadmin

7.2 Change the default host's server name and document root

By default Apache serves web files from /var/www/html; we change this directory to better integrate with a multi-host setup:

sudo nano -w /etc/apache2/sites-enabled/000-default.conf

Insert the following line at the top of the file:

ServerName HOSTNAME

This comment may be worth adding inside the <VirtualHost> configuration block:

# This first virtual host definition becomes the default. # Default is served for all requests not matching hosts below, # including requests by IP and requests for undefined hosts.

Add a ServerAlias line inside the <VirtualHost> configuration block:

ServerAlias www.HOSTNAME

Change the DocumentRoot line:

DocumentRoot "/var/www/www"

Ctrl+O, Enter (to save)
Ctrl+X (to exit nano)

Delete the previous html directory and create a new www directory
WARNING: all files in /var/www/html will be deleted!

rm -r /var/www/html mkdir /var/www/www

Validate your configuration and restart the server:

apache2ctl configtest sudo service apache2 restart

You may implement a website on the default host, however in this example setup we prefer to respond “404 Not Found” to all requests that don't match an expected virtual host subdomain:

nano /var/www/www/index.php

<?php http_response_code (404); header ('Content-Type: text/plain'); echo '404 Not Found'; die(); ?>

Ctrl+O, Enter (to save)
Ctrl+X (to exit nano)

Visiting any address that resolves to this server should now yield a 404 error, generated from /var/www/www/index.php; for example:

7.3 Reenable phpMyAdmin under a virtual host

sudo nano -w /etc/apache2/sites-enabled/000-default.conf

Append the following configuration block to the end of the file:

<VirtualHost *:80> DocumentRoot "/usr/share/phpmyadmin" ServerName phpmyadmin.HOSTNAME ServerAlias *.phpmyadmin.HOSTNAME </VirtualHost>

Ctrl+O, Enter (to save)
Ctrl+X (to exit nano)

Validate your configuration and restart the server:

apache2ctl configtest sudo service apache2 restart

Visiting http://phpmyadmin.HOSTNAME now accesses phpMyAdmin

7.4 Add additional virtual hosts, as desired

mkdir /var/www/delta mkdir /var/www/gamma

sudo nano -w /etc/apache2/sites-enabled/000-default.conf

Append the following configuration blocks to the end of the file:

Ctrl+O, Enter (to save)
Ctrl+X (to exit nano)

Validate your configuration and restart the server:

apache2ctl configtest sudo service apache2 restart

Access these sites via http://delta.HOSTNAME and http://gamma.HOSTNAME

8. Create a database and limited SQL user

Execute this SQL code from the phpMyAdmin [SQL] tab to create a database:

CREATE DATABASE `DBNAME` CHARACTER SET utf8mb4 COLLATE utf8mb4_unicode_ci;

Create a limited user who can only control this database:

phpMyAdmin → [Home] → [User accounts] → (DBUSER) → [Edit privileges] → [Change password]
Assign a password DBPASS to the database user

From PHP, this database can now be accessed through mysqli or equivalent:

$db = new mysqli ('localhost', 'DBUSER', 'DBPASS', 'DBNAME');

Appendix A: Changing passwords

If you need to change an account password after initial setup, use the following procedures:

A.1 Linux User

sudo passwd VMUSER

sudo may ask for a password; use OLD-VMPASS
when prompted for new UNIX password, enter NEW-VMPASS

sudo reboot

A.2 SQL User

mysqladmin --user=SQLUSER --password=OLD-SQLPASS password "NEW-SQLPASS"

sudo nano -w /etc/dbconfig-common/phpmyadmin.conf

Edit the line containing dbc_dbpass:

dbc_dbpass='NEW-SQLPASS'

Ctrl+O, Enter (to save)
Ctrl+X (to exit nano)

sudo nano -w /etc/phpmyadmin/config-db.php

Edit the line containing $dbpass:

$dbpass='NEW-SQLPASS';

Ctrl+O, Enter (to save)
Ctrl+X (to exit nano)

sudo service mysql restart sudo service apache2 restart

A.3 Samba User

sudo passwd SMBUSER

sudo may ask for a password; use VMPASS
when prompted for new UNIX password, enter NEW-SMBPASS

sudo smbpasswd SMBUSER

when prompted for password, enter NEW-SMBPASS

sudo service smbd restart

On Windows you may need to flush all open network connections to use new credentials; run this from a command prompt:

net use * /delete

Appendix B: Add a USB expansion card & connect a thermal printer

Connect a thermal receipt printer to a Linux VM in UnRAID: this guide provides troubleshooting suggestions and solutions for connecting a USB printer to the VM. It also outlines how to add a USB expansion card for exclusive use of the virtual machine.

Appendix C: Install the escpos-php receipt printer library

Install and test the escpos-php library: used for communicating with thermal receipt printers via the ESC/POS protocol.

Additionally, if your printer does not natively support printing QR codes, you can add image-based QR code support to the escpos-php library by integrating the PhpQrCode library.

Appendix D: Install the PHP Simple HTML DOM Parser

Install the SimpleHtmlDom library: This PHP library allows for exceptionally-easy web scraping and parsing of arbitrary HTML pages.

Appendix E: Mount a network share for read/write access

Mount a network share in Linux: This allows your VM to read from and write to shared folders on your network.

[end of guide]

A Verse of Unknown Origin

Sun, 05 Jan 2020 03:33:34 GMT

May everyone be happy.
May everyone be free of disease.
May auspiciousness be seen everywhere.
May suffering belong to no one.
Peace.