Categoria: webmaster

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php+bash script problem

If you call a bash script from a php one, be sure that you have the correct permissions. To grant them, you could have to do this command:

setfacl -m u:www-data:rwx /the/path/where/you/have/to/exec/bash
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Mariadb problem after upgrading to a linux lts release

If after a major upgrade (typically to a new LTS release) your maridb local server doesn’t work any more, it could be a problem of AppArmor settings.

To solve it you can try with

sudo nano /etc/apparmor.d/tunables/alias

and then, add the end of that file

alias /var/lib/mysql/ -> /your/mysql-data/path/,

and then

sudo systemctl reload apparmor

and

sudo systemctl start mariadb
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add an external md file to a php page

… and, of course see it as html, with the same graphical appearance of any other web text.

A way can be use a very light javascript, md-block.js, di Lea Verou.

Then you can add a function to your php website, like the following:

<?php
/* to call a file Markdown from a given folder */

function scheda_md($file)
{
    global $yourwebsite;

    $file = basename($file);

    return '<md-block src="' .
           $yourwebsite .
           '/the-path/where-are-md-files/from-yourwebsite-root' .
           htmlspecialchars($file, ENT_QUOTES, 'UTF-8') .
           '"></md-block>';
}
?>

And in the page where you want to show that md file you can use this code:

<?= scheda_md('the-md-name.md') ?>

add footnotes to embedded md file

I mean notes that should be correctly shown both in a webpage and in the standalone md file.
You have to modify the js (md-bloc.js), as you can see in the linked file.

In this way you can use the md syntax, such as:

[^1] (for the anchor) and
[^1]: for the footnote.

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drop-down menu not working

If in some websites their drop-down menu doesn’t work, you can check if you have enabled (in that websites) the “Absolute enable right click” extension, that can interfere heavily with javascript. Try to disable it, and you can see if that was the problem.

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Automatically list wp posts

You can list automatically wordpress posts in your php webpage, based on its tags.

The following php code allow you to list all wp posts with a given tag:

<?php

// --- 1️⃣ Caricamento WordPress (solo se non già caricato) ---
if (!function_exists('get_posts')) {
    $possible_paths = [
        __DIR__."/../[your-wp-path]/wp-load.php",  // standard
        __DIR__."/../../[your-wp-path]/wp-load.php", // if you inclyde subfolders
    ];
    foreach ($possible_paths as $path) {
        if (file_exists($path)) {
            require_once($path);
            break;
        }
    }
}

// --- 2️⃣ Preparazione query ---
global $post;
$args = [
    'posts_per_page' => 200,
];

if (!empty($whatcategory)) {
    $args['category_name'] = $whatcategory; // category slug 
}
if (!empty($whattag)) {
    // $args['tag'] = $whattag; 
    $args['tag_slug__in'] = array_map('trim', explode(',', $whattag)); // tag slug (not shown names)
}

// --- 3️⃣ Cache opzionale (transient WordPress) ---
$cache_key = 'lista_blog_' . ($whatcategory ?? 'none') . '_' . ($whattag ?? 'none');
$myposts = get_transient($cache_key);

if ($myposts === false) {
    $myposts = get_posts($args);
    set_transient($cache_key, $myposts, 3600); // cache 1 ora
}

// --- 4️⃣ Output ---
if (!empty($myposts)) {
    echo '<h2>
        <span lang="en">Our blog posts about this topic</span>
        <span lang="it">Posts del nostro blog su questo tema</span>
    </h2>
    <ul id="blog-posts">';

    foreach ($myposts as $post) {
        // Non dipendiamo dal loop globale
        echo '<li><a href="'.get_permalink($post).'" rel="bookmark">'.get_the_title($post).'</a></li>';
    }

    echo '</ul>';
    wp_reset_postdata();
}
?>

You can put this code in a separate file, and include it in your php webpage, i.g. in the footer, with a code like the following:

<?php
$listablog = "[the-path-of-your-separate-file/the-name-of-your-separate-file";
  if (file_exists($listablog)) {
    if (
        (isset($whatcategory) && !empty($whatcategory)) ||
        (isset($whattag) && !empty($whattag))
    ) {
        include $listablog;
    }
  }
?>

In the header of a webpage where you want add this list, you have to set the value of the tag you want list:
$whattag="your tag,another tag";

Be careful: you has to set, as value, not the visualized tag name, but the “slug”. You can see it also with mouse hover and status bar.

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Php variables in WordPress

To set a variable, such as an url, you can use the following steps:

  • add to your wp-config a code with something like 
require_once ABSPATH . 'wp-settings.php';
/** variabili */
define('GLOSSARIO_URL', 'yourwebsite/glossario.php');
  • add to functions.php (in your wp theme root) something like 
define('GLOSSARIO_URL', 'yourwebsite/glossario.php');

function glossario_link($atts) {
    $atts = shortcode_atts([
        'id' => '',
        'testo' => ''
    ], $atts);

    $url = GLOSSARIO_URL . '#' . $atts['id'];

    return '<a href="' . esc_url($url) . '">' . esc_html($atts['testo']) . '</a>';
}

add_shortcode('glossario', 'glossario_link');
  • in wp editor you will be able to call that code inserting a text like this:
[glossario id="universalismo" testo="universalisticamente"]

where the content of testo="" is what will appears in your wp page (while in the editor you will see that code)

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Fix a corrupt innodb

Today happened that mariadb worked almost correctly, but two wordpress db were incorrectly managed. Indeed I could modify a post, but I couldn’t add a new one.

In another PC I, luckily, had the good wp db (perfectlty working with its innodb). So, it was possible to fix this problem. With the following steps:

a) in the well working device dump (from a teminal) the working wp db:

mysqldump -u root -p --single-transaction --routines --triggers your-db-name > dump-yourdbname.sql

b) in the bad working device

  • activate (if not already active) mariadb
  • in a terminal: mysql -u root -p (of course you have to provide your mysql psw)
  • and then, within mysql, you have to delete the old, bad, db, and create a new one:
    • DROP DATABASE IF EXISTS yourdbname;
    • CREATE DATABASE yourdbname CHARACTER SET utf8mb4 COLLATE utf8mb4_unicode_ci;
    • EXIT;
  • Now you have a new, good but empty db. You have now to import the content of it, with this code: mysql -u root -p yourdbname < dump-yourdbname.sql

Now all should work 🙂.

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External markdown file in WordPress

If you want keep an external markdown file and include it in a WordPress page, you can follow these steps:

  • add a js file, such as md-block.js, in your js theme folder (typically /wp-content/themes/your-theme/js/ )
  • modify the functions.php file, in your root theme folder,. adding this code:
// per markdown BEGIN

function carica_md_block() {
    wp_enqueue_script(
        'md-block',
        get_stylesheet_directory_uri() . '/js/md-block.js',
        array(),
        null,
        true
    );
}
add_action('wp_enqueue_scripts', 'carica_md_block');

add_filter('script_loader_tag', function($tag, $handle, $src) {
    if ($handle === 'md-block') {
        return '<script type="module" src="' . esc_url($src) . '"></script>';
    }
    return $tag;
}, 10, 3);

function shortcode_scheda_md($atts) {
    $atts = shortcode_atts(array(
        'file' => ''
    ), $atts);

    $file = basename($atts['file']);

    if (empty($file) || pathinfo($file, PATHINFO_EXTENSION) !== 'md') {
        return '';
    }

    $url = content_url('/uploads/some-path/' . rawurlencode($file));

    return '<md-block src="' . esc_url($url) . '"></md-block>';
}
add_shortcode('scheda_md', 'shortcode_scheda_md');

// per markdown END
  • you can put your md files in the path above set: /uploads/some-path/ . Note that the folder some-path could be a symlinked one, from your local PC.
  • in the wordpress page when you want include a md file you can write,
    • using HTML (customized), [scheda_md file="the-name-of-the-file.md"],
    • or the code visualizaztion: something like[scheda_md]the-name-of-the-file.md[/scheda_md]
  • where that file, obviously, should be in /some-path/ folder.

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wp plugins

wp users

An useful wp plugin is wp users that allow you to collect subscriptions from the readers of your blog.

It has add-ons such as captcha that, linked with Google captcha, allow you to select humans from robots (and spam).

Be careful however to set v2 rather than v3, both in Google and in your wp plugin settings, otherwise you couldn’t be more able to login.