Category Archives: PHP

Why I think in Python is not a good idea to raise exceptions inside your methods

Last update: 2022-05-18 10:48 Irish Time

Recently a colleague was asking me for advice on their design of error handling in a Python application.

They were catching an error and raising an Exception, inside the except part of a method, to be catch outside the method.

And at some point a simple logic got really messy and unnecessarily complicated. Also troubleshooting and debugging an error was painful because they were only getting a Custom Exception and not context.

I explained to my colleague that I believed that the person that created that Exception chain of catch came from Java background and why I think they choose that path, and why I think in Python it’s a bad idea.

In Java, functions and methods can only return one object.

I programmed a lot in Java in my career, and it was a pain having to create value objects, and having to create all kind of objects for the return. Is it a good thing that types are strongly verified by the language? Yes. It worked? Yes. It made me invest much more time than necessary? Also yes.

Having the possibility to return only one object makes it mandatory having a way to return when there was an error. Otherwise you would need to encapsulate an error code and error description fields in each object, which is contrary to the nature of the object.

For example, a class Persona. Doesn’t make any sense having an attribute inside the class Persona to register if an operation related to this object went wrong.

For example, if we are in a class Spaceship that has a method GetPersonaInCommand() and there is a problem in that method, doesn’t make any sense to return an empty Persona object with attributes idError, errorDescription. Probably the Constructor or Persona will require at least a name or Id to build the object…. so in this case, makes sense that the method raises an Exception so the calling code catches it and knows that something went wrong or when there is no data to return.

This will force to write Custom Exceptions, but it’s a solution.

Another solution is creating a generic response object which could be an Object with these attributes:

  • idError
  • errorDescription
  • an Object which is the response, in our example Persona or null

I created this kind of approach for my Cassandra libraries to easily work with Cassandra from Java and from PHP, and for Cassandra Universal Driver (a http/s gateway created in year 2014).

Why this in not necessary in Python

Python allows you to return multiple values, so I encourage you tor return a boolean for indicating the success of the operation, and the object/value you’re interested.

You can see it easily if you take a look to FileUtils class from my OpenSource libraries carleslibs.

The method get_file_size_in_bytes(self, s_file) for example:

    def get_file_size_in_bytes(self, s_file):

        b_success = False
        i_file_size = 0

            # This will help with Unit Testing by raisin IOError Exception

            i_file_size = os.path.getsize(s_file)
            b_success = True
        except IOError:
            b_success = False

        return b_success, i_file_size

It will always return a boolean value to indicate success or failure of the operation and an integer for the size of the file.

The calling code will do something like this:

o_fileutils = FileUtils()
b_success, i_bytes = o_fileutils.get_file_size_in_bytes("profile.png")
if b_succes is False:
    print("Error! The file does not exist or cannot be accessed!")

if i_bytes < 1024:
    print("The profile picture should be at least 1KB")

print("Profile picture exists and is", i_bytes, " bytes in length!")

The fact that Python can return multiple variables makes super easy dealing with error handling without having to take the road of Custom Exceptions.

And it is Ok if you want to follow this path, but in my opinion, for most of the developers up to Senior levels, it only over complicates the logic of your code and the amount of try/excepts you have to have everywhere.

If you use PHP you can mix different types in an Array, so you can always return an Array with a boolean, or an i_id_error, and your object or data of whatever type it’s.

Getting back to my carleslibs Open Source package, it is super easy to Unit Test these methods.

In my opinion, this level of simplicity, brings only advantages. Including Software Development speed, which is good for the business.

I’m not advocating for not using Custom Exceptions or to not develop a Exceptions Raising strategy if you need it and you know what you’re doing. I’m just suggesting why I think most of the developments in Python do not really need this and only over complicates the development. There are situations where raising exceptions will be a perfectly useful or even the best approach, there are many scenarios, but I think that in most of cases, using raise inside except will only multiply the time of the development and slow down the speed of bringing new features to the business, over complicating Unit Test as well, and be a real pain for the Junior and Intermediate developers.

The Constructor

Obviously, as the Constructor doesn’t return any value, it is perfectly fine to raise an exception in there, or just to use try/except in the code that is instancing the objects.

News from the blog 2022-04-22


I was interviewed by Radio America Barcelona, in their studios in Barcelona.

RAB is a radio for the Catalan diaspora and expats.

The interview was broadcasted by Twitch and can be watched. It’s in Catalan language:

You can follow them:

Sant Jordi discounted books (promo)

Tomorrow 23th of April is Sant Jordi (Saint George), the patron of Catalonia, and the Catalan traditional celebration consist in this day women gifting a book to the men they love and men gifting a rose to the women they love.

I created a voucher for all my Python books, so, since during 23th of April you can acquire the four books per $10 USD in total.

This voucher is limited to 100 sales.

Python 3

I wrote an article with a Python 3 code that shows the length for file names in Linux ext3 and ext4 Filesystems and in ZFS Pools Filesystem.

I show basically how ASCii characters over 127 are encoded, reducing the maximum length of 255 bytes for the filename.


I’ve updated an article explaining how to create a ZPool raidz (RAID 5 equivalent) from three loop devices based on local files.

Thanks to those that bought my ZFS book this month. :)

HTML and JavaScript

I wrote a super simple code to hide the <p> using jQuery and JavaScript.

Free books

Books I bought

This month I bought these books.


I continued to block any Russian or Belarus Ip Address that connects to the blog.

I also started to block entire ranges of Ip’s from Digital Ocean, as many attacks come from Servers in their infrastructure.

Despite blocking tens of thousands of Ip Addresses, the number of visitors keep growing.

My Health

Thanks to my strict discipline I managed to recover super well and I’m healthier than before and guided by the satisfied doctors we removed two daily medicines.

I started a new medicine that is for the final phase of my recuperation, which doctors expect to be completely. In fact I’m much more healthier than I was before going to the hospital.


Will AI take the world?
Sadly, true history. The responsibility to deliver is from all of us.

News from the Blog 2022-02-22

My Open Source projects

zpool watch

zpool watch is a small Python program for Linux workstations with graphical environment and ZFS, that checks every 30 seconds if your OpenZFS pools are Ok.

If a pool is not healthy, it displays a message in a window using tk inter.

Basically allows you to skip checking from the terminal zpool status continuously or to having to customize the ZED service to send an email and having to figure out how to it can spawn a window alert to the graphical system or what to do if the session has not been initiated.


Since last News from the Blog I’ve released carleslibs v.1.06, v.1.0.5 and v.1.0.4.

v.1.0.6 adds a new class OsUtils to deal with mostly-Linux Os tasks, like knowing the userid, the username, if it’s root, the distribution name and kernel version.

It also adds:


In v.1.0.5 I’ve included a new method for getting the Datetime in Unix Epoc format as Integer and increased Code Coverage to 95% for ScreenUtils class.

v. 1.0.4 contains a minor update, a method in StringUtils to escape html from a string.

It uses the library html (part of Python core) so it was small work to do for me to create this method, and the Unit Test for it, but I wanted to use carleslibs in more projects and adding it as core functionality, makes the code of these projects I’m working on, much more clear.

I’m working in the future v.1.0.7.

I released the stable version 0.8.8 and tagged it.

Minor refactors and adding more Code Coverage (Unit Testing), and protection in the code for division per zero when seconds passed as int are 0. (this was not an actual error, but is worth protecting the code just in case for the future)

Working on branch 0.8.9.

Currently in Master there is a stable version of 0.8.9 mainly fixing which was not detecting when CTOP was running inside a Docker Container (reporting Unable to decode DMI).

My Books

Docker Combat Guide

Added 20 new pages with some tricks, like clearing the logs (1.6GB in my workstation), using some cool tools, using bind mounts and using Docker in Windows from command line without activating Docker Desktop or WSL.

BTW if you work with Windows and you cannot use Docker Desktop due to the new license, in this article I explain how to use docker stand alone in Windows, without using WSL.

ZFS on Ubuntu

One of my SATA 2TB 2.5″ 5,400 rpm drive got damaged and so was generating errors, so that was a fantastic opportunity to show how to detect and deal with the situation to replace it with a new SATA 2TB 3.5″ 7,200 rpm and fix the pool.

So I updated my ZFS on Ubuntu 20.04 LTS book.

Python 3

I’ve updated Python 3 Exercises for Beginners and added a new example of how to parse the <title> tag from an HTML page, using Beautifulsoup package, to the repository of Python 3 Combat Guide book.

I also added three new exercises, and solved them.

My friend Michela is translating the book to Italian. Thanks! :)

If you already purchased any of my books, you can download the updates of them when I upload them to LeanPub.

Free courses

Code Challenges

One of my students sent me this platform, which is kinda hackerrank, but oriented to video games. To solve code challenges by programming video games.

He is having plenty of fun:

More Symfony, APIs

If you enjoyed the Free Videos about Symfony, there is more.

It talks about a bundle for building APIs.

And this tutorial explains in detail how to work with Webpack Encore:

100 Days of Code: Python Bootcamp

A friend of mine, and colleague, Michela, is following this bootcamp and recommends it for people learning from ground 0.

My work at Blizzard

The company sent me the Stein, which is sent to the employees that serve for two years, with a recognition and a celebration called “The Circle of Honor”.

Books purchased

I bought this book as often I discover new ways, better, to explain the things to my students.

Sometimes I buy books for beginners, as I can get explained what I want to do super fast and some times they teach nice tricks that I didn’t know. I have huge Django books, and it took a lot to finish them.

A simpler book may only talk about how to install and work with it under a platform (Windows or Mac, as instance) but it is all that I require as the command to create projects are the same cross platform.

For example, you can get to install and to create a simple project with ORM, connected to the database, very quickly.


So I just discovered that Zoom has an option to draw in the shared screen, like Slack has. It is called Annotate. It is super useful for my classes. :)

Also discovered the icons in the Chat. It seems that not all the video calls accept it.


As Working From Home I needed an scanner, I looked in Amazon and all of them were costing more than €200.

I changed my strategy and I bought a All-In-One from HP, which costed me €68.

So I’ll have a scanner and a backup printer, which always comes handy.

The nightmare started after I tried to connect it with Ubuntu.

Ubuntu was not recognizing it. Checking the manuals they force to configure the printer from an Android/iPhone app or from their web page, my understanding is for windows only. In any case I would not install the proprietary drivers in my Linux system.

Annoyed, I installed the Android application, and it was requesting to get Location permissions to configure it. No way. There was not possible to configure the printer without giving GPS/Location permissions to the app, so I cancelled the process.

I grabbed a Windows 10 laptop and plugged the All-in-one through the USB. I ran the wizard to search for Scanners and Printers and was not unable to use my scanner, only to configure as a printer, so I was forced to install HP drivers.

Irritated I did, and they were suggesting to configure the printer so I can print from Internet or from the phone. Thanks HP, you’ll be the next SolarWinds big-security-hole. I said no way, and in order to use the Wifi I have to agree to open that security door which is that the printer would be connected to Internet permanently, sending and receiving information. I said no, I’ll use only via USB.

Even selecting that, in order to scan, the Software forces me to create an account.

Disappointing. HP is doing very big stupid mistakes. They used to be a good company.

Since they stopped doing the drivers in Barcelona years ago, their Software and solutions (not the hardware) went to hell.

I checked the reviews in the App Store and so many people gave them 1 star and have problems… what a shame the way they created this solution.


I made a donation to OpenShot Video Editor.

This is a great Open Source, multi-platform editor, so I wanted to support the creator.


Attacks: looking for exploits

This is just a sample of a set of attacks to the blog in a 3 minutes interval.

Another one this morning:

Now all are blocked in the Firewall.

This is a non stop practice from spammers and pirates that has been going on for years.

It was almost three decades ago, when I was the Linux responsible of an ISP, and I was installing a brand new Linux system connected to a service called “infovia”, at the time when Internet was used with dial-up and modems, and in the interval of time of the installation, it got hacked. I had the Ethernet connected. So then already, this was happening.

The morning I was writing this, I blocked thousands of offending Ip Addresses.

Protection solutions

I recommend you to use CloudFlare, is a CDN/Cache/Accelerator with DoS protection and even in its Free version is really useful.


So I come with a game kind of Quiz that you can play with your friends, family or work colleagues working from home (WFH).

The idea is that the master shares screen and sound in Zoom, and then the rest connect to and enter the code displayed on the master’s screen on their own browser, and an interactive game is started.

It is recommended that the master has two monitors so they can also play.

The games are so fun as a phrase appearing and people having to complete with a lie. If your friends vote your phrase, believing is true, you get points. If you vote the true answer, you get points too.

Very funny and recommendable.


<humor>Skynet sent another terminator to end me, but I terminated it. Its processor lays exhibited in my home now</humor>

I bought a laminator.

It has also a ruler and a trimmer to cut the paper.

It was only €39 and I’ve to say that I’m very happy with the results.

It takes around 5 minutes to be ready, it takes to get to the hot-enough temperature, and feeds the pages slowly, around 50 secs a DIN-A4, but the results are worth the time.

I’ve protected my medical receipts and other value documents and the work was perfect. No bubbles at all. No big deal if the plastic covers are introduced not 100% straight. Even if you pass again an already plasticized document, all is good.



One of my friends sent me this image.

It is old, but still it’s fun. So it assumes the cameras of the parking or speed cameras, will OCR the plate to build a query, and that the code is not well protected. So basically is exploiting a Sql Injection.

Anybody working on the systems side, and with databases, knows how annoying are those potential situations.

Python and coding

One of my colleagues shared this :)

News from the Blog 2022-01-22

News for the Blog

It has been 9 years since I created the blog, and some articles have old content that still get many visitors. To make sure they get the clear picture and not obsolete information, all the articles of the taxonomy POST, will include the Date and Time when the article was first published.

I also removed the annoying link “Leave a comment” on top. I think it influences some people to leave comments before actually having read the article.

It is still possible to add comments, but they are on the bottom of the page. I believe it makes more sense this way. This is the way.

Technically that involved modifying the files of my template:

  • functions.php
  • content.php

My Books

Automating and Provisioning to Amazon AWS using boto3 Amazon’s SDK for Python 3

I finished my book about Automating and Provisioning to Amazon AWS using boto3 Amazon’s SDK for Python 3.

It’s 128 pages in Full size DIN-A4 DRM-Free, and comes with a link to code samples of a real project CLI Menu based.

Docker Combat Guide

I have updated my book Docker Combat Guide and I added a completely new section, including source code, to work with Docker’s Python SDK.

I show the Docker SDK by showing the code of an actual CLI program I wrote in Python 3.

Here you can see a video that demonstrates how I launched a project with three Docker Containers via Docker compose. The Containers have Python, Flask webserver, and redis as bridge between the two Python Containers.

All the source code are downloadable with the book.

Watch at 1080p at Full Screen for better experience

My Classes

In January I resumed the coding classes. I have new students, and few spots free in my agenda, as some of my students graduated and others have been hired as Software Developers. I can not be more proud. :)

Free Training

Symfony is one of the most popular PHP Frameworks.

You can learn it with these free videos:

Software Licenses I Purchased

Before leaving 2021, I registered WinRAR for Windows.

WinRAR is a compressing Software that has been with us for 19 years.

I’m pretty sure I registered it in the past, but these holidays I was out only with two Window laptops and I had to do some work for the university and WinRAR came it handy, so I decided to register it again.

I create Software and Books, and I earn my life with this, so it makes a lot of sense to pay others for their good work crafting Software.

Books I Purchased

I bought this book and by the moment is really good. I wanted to buy some updated books as all my Linux books have some years already. Also I keep my skills sharp by reading reading reading.

Hardware I purchased

So I bought a cheap car power inverter.

The ones I saw in Amazon were €120+ and they were not very good rated, so I opted to buy a cheap one in the supermarket and keep it on the car just in case one day I need it. (My new Asus Zenbook laptop has 18 hours of autonomy and I don’t charge it for days, but you never know)

For those that don’t know, a power inverter allows you to get a 220V (120V in US) plug, from the connection of the lighter from your car. Also you can get the energy from an external car battery. This comes in really handy to charge the laptop, cameras, your drone… if you are in the nature and you don’t have any plug near.

I bought one years ago to power up Raspberry Pi’s when I was doing Research for a project I was studying to launch.


Many friends are using Starlink as a substitute of fiber for their rural homes, and they are super happy with it.

One of them send me a very fun article.

It is in Italian, but you can google translate it.

Anyways you can get the idea of what’s going on in the picture :)

So tell me… so your speed with Starlink drops 80% in winter uh… aha…

Random news about Software

I tried the voice recognition in Slack huddle, and it works pretty well. Also Zoom has this feature and they are great. Specially when you are in a group call, or in a class.

My health

I was experimenting some problems, so I scheduled an appointment to get blood analysis and to be checked. Just in case.

TL;TR I could have died.

The doctors saw my analysis and sent me to the hospital urgently, where they found something that was going to be lethal. For hours they were checking me and doing several more analysis and tests to discard false positives, etc… and they precisely found the issue and provided urgent treatment and confirmed that I could have died at any moment.

Basically I dodged a bullet.

I was doing certain healthy things that helped me in a situation that could have been deadly or extremely dangerous to my health.

With the treatment and my strict discipline, I reverted the situation really quick and now I have more health and more energy than before. I feel rejuvenated.

I’m feeling lucky that with my work, the classes, the books I wrote, etc… I didn’t have to worry about the expensive medicines, the transport, etc… It was a bad moment, during Christmas, with so many people on holidays, pharmacies and GPs closed, so I had to spend more time looking for, traveling, and to pay more than it would had been strictly necessary. Despite all the time I used to my health, I managed to finish my university duties on time, and I didn’t miss my duties at work after the hospital, neither I had to cancel any programming classes or mentoring sessions. Nobody out of my closest circle knew what was going on, with the exception of my boss, which I kept informed in real time, just in case there was any problem, as I didn’t want to let down the company and have my duties at work to be unattended if something major happened.

I was not afraid to die. Unfortunately I’ve lost very significant people since I was a child. Relatives, very appreciated bosses and colleagues which I considered my friends, and great friends of different circles. Illnesses, accidents, and a friend of mine committed suicide years ago, and some of my partners attempted it (before we know each other). When you see people that are so good leaving, this brings a sadness that cannot be explained with words. I have had a tough life.

We have a limited time, and he have freedom to make choices. Some people choose to be miserable, to mistreat others, to lie, to cheat, to be unfaithful, to lack ethic and integrity. Those are their choices. Their wasted time will not come back.

Some of my friends are doctors. I admire them. They save lives and improve the quality of life of people with health problems.

I like being an Engineer cause I can create things, I can build instead of destroy, I can help to improve the world, and I can help users to have a good time and to avoid the frustration of services being down. I chose to do a positive work. So many times I’ve been offered much bigger salaries to do something I didn’t like, or by companies that I don’t admire, and I refused. Cause I wanted to make a better world. I know many people don’t think like that, and they only take take take. They are even unable to understand my choices, even to believe that I’m like that. But it’s enough that I know what I’m doing, and that it makes sense for me, and that I know that I’m doing well. And then, one day, you realize, that doing well, being fair and nice even if other people stabbed you in the back, you got to know fantastic people like you, and people that adore you and love to have you in their life, in their companies… So I’m really fortunate. To all the good-hearted people around, that give without expect anything in return, that try to make the world a better place, thank you.

News of the blog 2021-08-16

  • I completed my ZFS on Ubuntu 20.04 LTS book.
    I had an error in an actual hard drive so I added a Troubleshooting section explaining how I fixed it.
  • I paused for a while the advance of my book Python: basic exercises for beginners, as my colleague Michela is translating it to Italian. She is a great Engineer and I cannot be more happy of having her help.
  • I added a new article about how to create a simple web Star Wars game using Flask.
    As always, I use Docker and a Dockerfile to automate the deployment, so you can test it without messing with your local system.
    The code is very simple and easy to understand.
mysql> UPDATE wp_options set option_value='blog.carlesmateo.local' WHERE option_name='siteurl';
Query OK, 1 row affected (0.02 sec)
Rows matched: 1 Changed: 1 Warnings: 0

This way I set an entry in /etc/hosts and I can do all the tests I want.

  • I added a new section to the blog, is a link where you can see all the articles published, ordered by number of views.

Is in the main page, just after the recommended articles.
Here you can see the source code.

  • I removed the Categories:
    • Storage
      • ZFS
  • In favor of:
    • Hardware
      • Storage
        • ZFS
  • So the articles with Categories in the group deleted were reassigned the Categories in the second group.
  • Visually:
    • I removed some annoying lines from the Quick Selection access.
      They came from inherited CSS properties from my WordPress, long time customized, and I created new styles for this section.
    • I adjusted the line-height to avoid separation between lines being too much.
  • I added a link in the section of Other Engineering Blogs that I like, to the great site, author of many super cool WordPress plugins.

My PHP Script to see WordPress Posts and Views ordered by Views

This article shows the code for my PHP program posts_and_views.php that you can see at the bottom of in the Quick Selection bar.

Page rendered of all my Published Posts sorted by Views

So I wrote this small PHP Code to display the number of Post Views recorded in my WordPress Database, sorted by Views in descending order.

In other words, sorted from Most Viewed.

Please note: In order to track the post views I use the excellent plugin WP-PostViews by Lester ‘GaMerZ’ Chan

Here is the code for posts_and_views.php

As you can see I use wp-config.php file to get the Database Settings (username, password, database) but I don’t use the WordPress Engine, it is just a stand alone PHP. So I wrote my own function to get the slug based on the category name. I believe the slug for it is in the Database and I could have added this as a SubQuery with JOINs, which would be better, but I wanted to keep the Database workload lightweight and especially, I did not want to invest more time investigating how the get the slug.

As I tested my function I didn’t find any Category failing but I saw that I had the Category Storage repeated in two different structure tree in Categories, and I will only always link to just the first one (So I was not linkin to the slug storage-2). I fixed that Category that I found repeated but to be honest if this script was a commercial solution or an Open Source solution properly maintained rather than just a sample, I would update it to have Categories and Tags’ slugs coming from the Database.

I would probably make it work with a Cron that would generate a cached page, updated every hour or every ten minutes. I did this in other projects I worked or in my PHP Framework Catalonia Framerwork.

But honestly, the load of the page does not justify a major effort in optimizing here, in this case.

<!DOCTYPE html>
        .first {

            background-color: blue;
            padding: 12px;
        .second {
            background-color: rgba(254, 253, 252, 0.7);
            text-align: center;
            padding:20px 0;
            font-size: 20px;

        .centered {
            text-align: center;

        /* unvisited link */
        a:link {
            color: blue;
            text-decoration: none;

        /* visited link */
        a:visited {
            color: blue;
            text-decoration: none;

        /* mouse over link */
        a:hover {
            color: #00A8EF;
            text-decoration: underline;

        /* selected link */
        a:active {
            color: blue;

include "wp-config.php";

$s_site_name = "Carles Mateo's blog";
$s_site_link = "";

function get_category_slug($s_text) {
    $s_output_text = strtolower($s_text);
    $s_output_text = str_replace(" ", "-", $s_output_text);

    return $s_output_text;

<h1><a href="<?php print $s_site_link; ?>"><?php print($s_site_name); ?></a></h1>

$s_sort = "views DESC, post_date, post_title DESC";

if (array_key_exists("sort", $_GET)) {
    if ($_GET["sort"] == "date") {
        $s_sort = "post_date, views, post_title";

$s_servername = "localhost";
$s_database = DB_NAME;
$s_username = DB_USER;
$s_password = DB_PASSWORD;

// Create connection
$o_conn = new mysqli($s_servername, $s_username, $s_password, $s_database);

// Check connection
if ($o_conn->connect_error) {
    die("Connection failed: " . $o_conn->connect_error);

mysql> DESCRIBE wp_posts;
| Field                 | Type            | Null | Key | Default             | Extra          |
| ID                    | bigint unsigned | NO   | PRI | NULL                | auto_increment |
| post_author           | bigint unsigned | NO   | MUL | 0                   |                |
| post_date             | datetime        | NO   |     | 0000-00-00 00:00:00 |                |
| post_date_gmt         | datetime        | NO   |     | 0000-00-00 00:00:00 |                |
| post_content          | longtext        | NO   |     | NULL                |                |
| post_title            | text            | NO   |     | NULL                |                |
| post_excerpt          | text            | NO   |     | NULL                |                |
| post_status           | varchar(20)     | NO   |     | publish             |                |
| comment_status        | varchar(20)     | NO   |     | open                |                |
| ping_status           | varchar(20)     | NO   |     | open                |                |
| post_password         | varchar(255)    | NO   |     |                     |                |
| post_name             | varchar(200)    | NO   | MUL |                     |                |
| to_ping               | text            | NO   |     | NULL                |                |
| pinged                | text            | NO   |     | NULL                |                |
| post_modified         | datetime        | NO   |     | 0000-00-00 00:00:00 |                |
| post_modified_gmt     | datetime        | NO   |     | 0000-00-00 00:00:00 |                |
| post_content_filtered | longtext        | NO   |     | NULL                |                |
| post_parent           | bigint unsigned | NO   | MUL | 0                   |                |
| guid                  | varchar(255)    | NO   |     |                     |                |
| menu_order            | int             | NO   |     | 0                   |                |
| post_type             | varchar(20)     | NO   | MUL | post                |                |
| post_mime_type        | varchar(100)    | NO   |     |                     |                |
| comment_count         | bigint          | NO   |     | 0                   |                |

mysql> describe wp_postmeta;
| Field      | Type            | Null | Key | Default | Extra          |
| meta_id    | bigint unsigned | NO   | PRI | NULL    | auto_increment |
| post_id    | bigint unsigned | NO   | MUL | 0       |                |
| meta_key   | varchar(255)    | YES  | MUL | NULL    |                |
| meta_value | longtext        | YES  |     | NULL    |                |

$s_sql = "SELECT DISTINCT post_title, post_content,
                 (SELECT CAST(meta_value AS SIGNED) FROM wp_postmeta WHERE wp_postmeta.meta_key = 'views' AND wp_postmeta.post_id = wp_posts.ID) AS 'views',
                 (SELECT group_concat( separator ',') 
                         FROM wp_terms
                  INNER JOIN wp_term_taxonomy 
                          ON wp_terms.term_id = wp_term_taxonomy.term_id
                  INNER JOIN wp_term_relationships wpr 
                          ON wpr.term_taxonomy_id = wp_term_taxonomy.term_taxonomy_id
                         taxonomy= 'category' AND wp_posts.ID = wpr.object_id
                ) AS 'Categories',
                (SELECT group_concat( separator ', ') 
                        FROM wp_terms
                 INNER JOIN wp_term_taxonomy 
                         ON wp_terms.term_id = wp_term_taxonomy.term_id
                 INNER JOIN wp_term_relationships wpr 
                         ON wpr.term_taxonomy_id = wp_term_taxonomy.term_taxonomy_id
                        taxonomy= 'post_tag' AND wp_posts.ID = wpr.object_id
                ) AS 'Tags',
               ID, post_name, post_date, post_modified, post_type
          FROM wp_posts
                post_type = 'post' AND post_status = 'publish'
          ORDER BY

$o_result = $o_conn->query($s_sql);

if ($o_result->num_rows > 0) {
    ?><table style="border:1px solid">
    <tr class="first"><th>Title</th><th style="min-width:100px">Views</th><th style="min-width:150px">Creation Date</th><th>Categories</th><th>Tags</th></tr>

    $i_total_views = 0;
    $i_articles = 0;

    // output data of each row
    while($row = $o_result->fetch_assoc()) {
        $s_style='style="border:1px solid"';
        $s_url = $row['post_name'];
        print("<td $s_style>");
        print('<a href="'.$s_url.'" target="_blank">');
        print('<td class="centered" '.$s_style.'>');
        print("<td $s_style>");
        print("<td $s_style>");
        $s_categories = $row["Categories"];
        $a_categories = explode (",", $s_categories);
        $s_categories_content = "";
        foreach($a_categories as $s_category) {
            $s_category_slug = "/category/".get_category_slug($s_category)."/";
            $s_categories_content = $s_categories_content .'<a href="'.$s_category_slug.'" target="_blank">';
            $s_categories_content = $s_categories_content .$s_category;
            $s_categories_content = $s_categories_content ."</a>, ";

        if (strlen($s_categories_content) > 0) {
            $s_categories_content = substr($s_categories_content, 0, -2);

        print("<td $s_style>");
        // $row["post_content"];
        $i_total_views = $i_total_views + intval($row["views"]);
        echo "</tr>";
    } ?></table><?php
    print("<strong>Total articles:</strong> ".number_format($i_articles)." <strong>Total Views:</strong> ".number_format($i_total_views));
} else {
    echo "<p>0 results</p>";


News from the blog 2021-01-11

Happy New Year to all.

Is something very simple, but will help my student friends to validate Input from Keyboard without losing too many hours.

The Input Validation Classes I create in PHP for Privalia or in my PHP Catalonia Framework, are much, much, more powerful, allowing the validation of complete forms, rendering errors, etc… although they were created for Web, and not for Keyboard input.

It recursively goes to all the subdirectories looking for .py files, and then it counts the lines.

  • I updated the price of my books to be the minimum allowed by LeanPub, to $5 USD, and created a bundle of two of them for $7 USD.

So people can benefit from this during the lock down.

  • I’ve updated the Python Combat Guide book with a sample of using Paramiko Libraries for SSH, and increased the Object Oriented Programing and Unit Testing, sections. I also added some books to the Bibliography.
  • I’ve read the postmortem initial analysis from Slack’s incident. It’s really interesting.

I cannot share it, but I guess that at some point they will publish it on their blog:

  • As I’m giving more Python Classes I decided to write a book to teach to code in Python for non-programmers.