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PyCoder’s Weekly: Issue #643 (Aug. 20, 2024)
#643 – AUGUST 20, 2024
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The Scrapy crawl stat logs are useful for tracking and monitoring the performance of a spider. If you want to keep them longer rather than just see the console printout, you can have them written to a database.
XIEGERTS.COM • Shared by Stephen
In this video course, you’ll learn how to use Python to communicate with REST APIs. You’ll learn about REST architecture and how to use the requests library to get data from a REST API. You’ll also explore different Python tools you can use to build REST APIs.
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argparse, the standard library module that Django uses for parsing command line options, supports sub-commands. These are pretty neat for providing an expansive API without hundreds of individual commands. This article shows you how to write your own.
ADAM JOHNSON
When crawling websites with Scrapy you’ll quickly come across all sorts of scenarios that require you to get creative or interact with the page that you’re trying to scrape. One of these scenarios is when you need to crawl an infinite scroll page. This type of website page loads more content as you scroll down the page like a social media feed.
STEPHEN SIEGERT • Shared by Stephen Siegert
SQL injection is the process of tricking a database into doing unintended things by modifying the input values to a query. Boolean-based blind injection is a subset that reveals structural information about the database. These can be hard to craft by hand, this article shows you how to automate the process to help do penetration testing.
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If you use Python’s print() function to get information about the flow of your programs, then logging is the natural next step for you. This tutorial will guide you through creating your first logs and show you ways to curate them to grow with your projects.
REAL PYTHON
How costly it is to call functions and builtins in your python code? Does inlining help? How have the recent CPython releases improved performance in these areas? This article dives deep on function performance.
ABHINAV UPADHYAY
On *nix systems with GDB installed, you can attach to already running processes. This article shows you how to combine that with Python’s PDB debugger to then add breakpoints to Python in a running script.
DOMINIK CZARNOTA
This is a deeper dive into types and Pydantic around how to build “correct by construction” design patterns. Building your objects so that validation becomes a single call.
WILLIAM WOODRUFF
PyTorch vs Tensorflow: Which one should you use? Learn about these two popular deep learning libraries and how to choose the best one for your project.
REAL PYTHON
Have you ever wanted to create a plot or graph in your terminal? Learn how with the textual-plotext package.
MIKE DRISCOLL
A list of things to check when something works on your computer but not on someone else’s.
MATHEUS RICHARD
Juan talks about his love for the uv tool and how it has simplified Python packaging.
JUAN LUIS CANO RODRIGUEZ
GITHUB.COM/BNKC • Shared by lev ostatnigrosh
Events Weekly Real Python Office Hours Q&A (Virtual) August 21, 2024
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August 21 to August 23, 2024
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August 23 to August 26, 2024
KIWIPYCON.NZ
August 24, 2024
MEETUP.COM
August 26 to August 31, 2024
EUROSCIPY.ORG
August 29 to September 1, 2024
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Happy Pythoning!
This was PyCoder’s Weekly Issue #643.
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Stack Abuse: Building Custom Email Templates with HTML and CSS in Python
An HTML email utilizes HTML code for presentation. Its design is heavy and looks like a modern web page, rich with visual elements like images, videos, etc., to emphasize different parts of an email's content.
Building email templates tailored to your brand is useful for various email marketing purposes such as welcoming new customers, order confirmation, and so on. Email template customization allows you to save time by not having to create emails from scratch each time. You can also include an email link in HTML to automatically compose emails in your email client.
In this step-by-step guide, you'll learn how to build an HTML email template, add a CSS email design to it, and send it to your target audience.
Setting Up Your Template Directory and Jinja2Follow the steps below to set up your HTML email template directory and Jinja2 for Python email automation:
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Create a Template Directory: To hold your HTML email templates, you will need to set up a template directory inside your project module. Let's name this directory - html_emailtemp.
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Install Jinja2: Jinja is a popular templating engine for Python that developers use to create configuration files, HTML documents, etc. Jinja2 is its latest version. It lets you create dynamic content via loops, blocks, variables, etc. It's used in various Python projects, like building websites and microservices, automating emails with Python, and more.
Use this command to install Jinja2 on your computer:
pip install jinja2
To create an HTML email template, let's understand how to code your email step by step. If you want to modify your templates, you can do it easily by following the steps below:
Step 1: Structure HTMLA basic email will have a proper structure - a header, a body, and a footer.
- Header: Used for branding purposes (in emails, at least)
- Body: It will house the main text or content of the email
- Footer: It's at the end of the email if you want to add more links, information, or call-to-actions (CTA)
Begin by creating your HTML structure, keeping it simple since email clients are less compatible than web browsers. For example, using tables is preferable for custom email layouts.
Here's how you can create a basic HTML mail with a defined structure:
<!DOCTYPE html> <html lang="en"> <head> <meta charset="UTF-8"> <meta name="viewport" content="width=device-width, initial-scale=1"> <title>HTML Email Template</title> <style type="text/css"> /* Add your CSS here */ </style> </head> <body> <table width="100%" cellpadding="0" cellspacing="0"> <tr> <td align="center"> <table width="600" cellpadding="0" cellspacing="0"> <!-- Header --> <tr> <td style="background-color: #1c3f60; color: #ffffff; text-align: center; padding: 20px;"> <h1>Your order is confirmed</h1> </td> </tr> <!-- Body --> <tr> <td style="padding: 20px; font-size: 16px; line-height: 1.6; color:#ffffff;"> <p>The estimated delivery date is 22nd August 2024.</p> </td> </tr> <!-- Footer --> <tr> <td style="background-color: #ff6100; color: #000000; text-align: center; padding: 20px;"> <p>For additional help, contact us at support@domain.com</p> </td> </tr> </table> </td> </tr> </table> </body> </html>Explanation:
- <!DOCTYPE html>: This declares HTML as your document type.
- <html>: This is an HTML page's root element.
- <head>: This stores the document's metadata, like CSS styles.
- <style>: CSS styles are defined here.
- <body>: This stores your email's main content.
- <table>: This tag defines the email layout, giving it a tabular structure with cells and rows, which makes rendering easier for email clients.
- <tr>: This tag defines the table's row, allowing vertical content stacking.
- <td>: This tag is used to define a cell inside a row. It contains content like images, text, buttons, etc.
Now, let's create the structure of your HTML email. To ensure it's compatible with different email clients, use tables to generate a custom email layout, instead of CSS.
<table width="100%" cellpadding="0" cellspacing="0"> <tr> <td align="center"> <table width="600" cellpadding="0" cellspacing="0" style="border: 1px solid #1c3f60; padding: 20px;"> <tr> <td align="center"> <h1 style="color: #7ed957;">Hi, Jon!</h1> <p style="font-size: 16px; color: #ffde59;">Thank you for being our valuable customer!</p> </td> </tr> </table> </td> </tr> </table> Styling the Email with CSSOnce you've defined your email structure, let's start designing emails with HTML and CSS:
Inline CSSUse inline CSS to ensure different email clients render CSS accurately and preserve the intended aesthetics of your email style.
<p style="font-size: 16px; color: blue;">Styled paragraph.</p> Adjusting StyleUsers might use different devices and screen sizes to view your email. Therefore, it's necessary to adapt the style to suit various screen sizes. In this case, we'll use media queries to achieve this goal and facilitate responsive email design.
<style type="text/css"> @media screen and (max-width: 600px) { .container { width: 100% !important; padding: 10px !important; } } </style> <table class="container" width="600"> <!-- Content --> </table>Explanation:
- @media screen and (max-width: 600px) {....}: This is a media query that targets device screens of up to 600 pixels, ensuring the style applies only to these devices, such as tablets and smartphones.
- width: 100% !important;: This style changes the width of the table - .container. The code instructs that the table width be set to full screen, not 600px.
- !important: This rule overrides other styles that may conflict with it.
- padding: 10px !important;: Inside the .container table, a padding of 10px is added to the table.
Here, we are adding a call to action (CTA) link at the button - "Get a 30-day free trial" that points to this page - https://www.mydomain.com.
<table cellpadding="0" cellspacing="0" style="margin: auto;"> <tr> <td align="center" style="background-color: #8c52ff; padding: 10px 20px; border-radius: 5px;"> <a href="https://www.mydomain.com" target="_blank" style="color: #ffffff; text-decoration: none; font-weight: bold;">Get a 30-day free trial</a> </td> </tr> </table>Let's Now Look at the Complete HTML Email Template:
<!DOCTYPE html> <html lang="en"> <head> <meta charset="UTF-8"> <meta name="viewport" content="width=device-width, initial-scale=1"> <title>HTML Email Template</title> <style type="text/css"> /* Adding the CSS */ body { margin: 0; padding: 0; background-color: #f4f4f4; font-family: Arial, sans-serif; } table { border-collapse: collapse; } .mailcontainer { width: 100%; max-width: 600px; margin: auto; background-color: #ffffff; } .header { background-color: #1c3f60; color: #ffffff; text-align: center; padding: 20px; } .body { padding: 20px; font-size: 16px; line-height: 1.6; background-color: #1c3f60; color: #7ed957; } .footer { background-color: #ff6100; color: #000000; text-align: center; padding: 20px; } .cta { background-color: #8c52ff; padding: 10px 20px; border-radius: 5px; color: #ffffff; text-decoration: none; font-weight: bold; } @media screen and (max-width: 600px) { .container { width: 100% !important; padding: 10px !important; } } </style> </head> <body> <table width="100%" cellpadding="0" cellspacing="0"> <tr> <td align="center"> <table class="container" width="600" cellpadding="0" cellspacing="0"> <!-- Header --> <tr> <td class="header"> <h1>Your order is confirmed</h1> </td> </tr> <!-- Body --> <tr> <td class="body"> <p>The estimated delivery date is 22nd August 2024.</p> <p style="font-size: 16px; color: blue;">Styled paragraph.</p> <table width="100%" cellpadding="0" cellspacing="0" style="border: 1px solid #1c3f60; padding: 20px;"> <tr> <td align="center"> <h1 style="color: #7ed957;">Hi, Jon!</h1> <p style="font-size: 16px; color: #ffde59;">Thank you for being our valuable customer!</p> </td> </tr> </table> <table cellpadding="0" cellspacing="0" style="margin: auto;"> <tr> <td align="center" style="background-color: #8c52ff; padding: 10px 20px; border-radius: 5px;"> <a href="https://www.mydomain.com" target="_blank" rel="noopener noreferrer" style="color: #ffffff; text-decoration: none; font-weight: bold;">Get a 30-day free trial</a> </td> </tr> </table> </td> </tr> <!-- Footer --> <tr> <td style="background-color: #ff6100; color: #000000; text-align: center; padding: 20px;"> <p>For additional help, contact us at support@domain.com</p> </td> </tr> </table> </td> </tr> </table> </body> </html>Explanation:
- .mailcontainer: This is a class that you can use to style your email content's main section. It's given a set width, margin, border, and color.
- .header, .footer, .body: These are classes used to style your email's header, footer, and body, respectively.
- .cta: This class allows you to style your buttons, such as CTA buttons, with a specified color, border design, padding, etc.
Having created our HTML template, it's now time to bring everything together using the Jinja2 templating engine.
Import Project ModulesYou've already set up your template directory - html_emailtemp. Now you can find and render templates using code. But before you do that, import the relevant project modules using the code below:
from jinja2 import Environment, PackageLoader, select_autoescape env = Environment(loader=PackageLoader('email_project', 'html_emailtemp'), autoescape=select_autoescape(['html', 'xml']))Explanation:
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Environment: Jinja2 utilizes a central object, the template Environment. Its instances store global objects and configurations, and load your email templates from a file.
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PackageLoader: This configures Jinja2 to load email templates.
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autoescape: To mitigate security threats such as cross-site scripting (XSS) attacks and protect your code, you can escape values (that are passed to the email template) while rendering HTML using the command autoescape. Or, you can validate user inputs to reject malicious code.
For security, autoescape is set to True to enable escaping values. If you turn it to False, Jinja2 won't be able to escape values, and XSS attacks may occur. To enable autoescape, set autoescape to True:
env = Environment(loader=PackageLoader("myapp"), autoescape=True)
Once done, a template environment will be created with a template loader to find email templates created inside your project module's template folder.
Next, load your HTML email template using the method - get_template(). This function will return your loaded template. It also offers several benefits such as enabling email template inheritance, so you can reuse the template in multiple scenarios.
template1 = env.get_template("myemailtemplate.html")
Render the TemplateTo render your email template, use the method - render()
html1 = template1.render()
As these HTML email templates are dynamic, you can pass keyworded arguments (kwargs) with Jinja2 to the render function. The kwargs will then be passed to your email template. Here's how you can render your templates using the destined user's name - "Jon Doe" - in your email.
html1 = template1.render(name="Jon Doe")
Let's look at the complete code for this section:
from jinja2 import Environment, PackageLoader, select_autoescape env = Environment(loader=PackageLoader("email_project", "html_emailtemp"), autoescape=select_autoescape(["html", "xml"])) template1 = env.get_template("myemailtemplate.html") html1 = template1.render() Sending the EmailTo send an email, you can use the application-level, straightforward protocol - Simple Mail Transfer Protocol (SMTP). This protocol streamlines the email sending process and determines how to format, send, and encrypt your emails between the source and destination mail servers.
In this instance, we'll send emails in Python via SMTP since Python offers a built-in module for email sending. To send emails, Python provides a library, 'smtplib', to facilitate effortless interaction with the SMTP protocol.
To get started:
Install 'smtplib': Ensure you have installed Python on your system. Now, import 'smtplib' to set up connectivity with the mail server.
import smtplib
Define your HTML parameter: Define your HTML parameter for the mail object where you'll keep your HTML template. It will instruct email clients to render the template.
Here's the full code for this section:
import smtplib from email.mime.text import MIMEText # MIMEText is a class from the email package from jinja2 import Template # Let's use Template class for our HTML template sender = "<a href='mailto:sender1@gmail.com' target='_blank' rel='noopener noreferrer'>sender1@gmail.com</a>" recipient = "<a href='mailto:recipient1@gmail.com' target='_blank' rel='noopener noreferrer'>recipient1@gmail.com</a>" subject = "Your order is confirmed!" with open('myemailtemplate.html', 'r') as f: template1 = Template(f.read()) # Enter the HTML template html_emailtemp = """ <!DOCTYPE html> <html lang='en'> <head> <meta charset='UTF-8'> <meta name='viewport' content='width=device-width, initial-scale=1'> <title>HTML Email Template</title> <style type='text/css'> # Adding the CSS body { margin: 0; padding: 0; background-color: #f4f4f4; font-family: Arial, sans-serif; } table { border-collapse: collapse; } .mailcontainer { width: 100%; max-width: 600px; margin: auto; background-color: #ffffff; } .header { background-color: #1c3f60; color: #ffffff; text-align: center; padding: 20px; } .body { padding: 20px; font-size: 16px; line-height: 1.6; background-color: #1c3f60; color: #7ed957; } .footer { background-color: #ff6100; color: #000000; text-align: center; padding: 20px; } .cta { background-color: #8c52ff; padding: 10px 20px; border-radius: 5px; color: #ffffff; text-decoration: none; font-weight: bold; } @media screen and (max-width: 600px) { .container { width: 100% !important; padding: 10px !important; } } </style> </head> <body> <table width='100%' cellpadding='0' cellspacing='0'> <tr> <td align='center'> <table class='container' width='600' cellpadding='0' cellspacing='0'> <!-- Header --> <tr> <td class='header'> <h1>Your order is confirmed</h1> </td> </tr> <!-- Body --> <tr> <td class='body'> <p>The estimated delivery date is 22nd August 2024.</p> <p style='font-size: 16px; color: blue;'>Styled paragraph.</p> <table width='100%' cellpadding='0' cellspacing='0' style='border: 1px solid #1c3f60; padding: 20px;'> <tr> <td align='center'> <h1 style='color: #7ed957;'>Hi, Jane!</h1> <p style='font-size: 16px; color: #ffde59;'> Thank you for being our valuable customer! </p> </td> </tr> </table> <table cellpadding='0' cellspacing='0' style='margin: auto;'> <tr> <td align='center' style='background-color: #8c52ff; padding: 10px 20px; border-radius: 5px;'> <a href='https://www.mydomain.com' target='_blank' rel='noopener noreferrer' style='color: #ffffff; text-decoration: none; font-weight: bold;'>Get a 30-day free trial</a> </td> </tr> </table> </td> </tr> <!-- Footer --> <tr> <td style='background-color: #ff6100; color: #000000; text-align: center; padding: 20px;'> <p>For additional help, contact us at support@domain.com</p> </td> </tr> </table> </td> </tr> </table> </body> </html> """ template1 = Template(html_emailtemp) html1 = template1.render(name="Jon Doe") # Attach your MIMEText objects for HTML message = MIMEText(html1, 'html') message['Subject'] = subject message['From'] = sender message['To'] = recipient # Send the HTML email with smtplib.SMTP_SSL('smtp.gmail.com', 465) as server: server.login(username, password) server.sendmail(sender, recipient, message.as_string())Explanation:
- sender: The sender's email address
- recipient: The recipient's email address
- from email.mime.text import MIMEText: This is used to import the class MIMEText, enabling you to attach your HTML template in the email.
- smtplib.SMTP_SSL('smtp.gmail.com', 465) as server:: This establishes a connection with your email provider's (Gmail's) SMTP server using port 465. If you are using another SMTP provider, use their domain name, such as smtp.domain.com, with an appropriate port number. The connection is secured with SSL.
- server.login(username, password): This function allows you to log in to the email server using your username and password.
- server.sendemail(sender, recipient, message.as_string()): This command sends the HTML email.
Before sending your HTML email, test it to understand how different email clients render CSS and HTML. Testing tools like Email on Acid, Litmus, etc. can assist you.
ConclusionTo build custom email templates with HTML and CSS in Python, follow the above instructions. First, begin structuring your HTML email template, style emails with CSS, and then send them to your recipients. Always check your email template's compatibility with different email clients and ensure to keep your HTML simple using tables. Adding an email link in HTML will also allow you to compose an email automatically in your email client and send it to a specific email address.
Matt Glaman: Next stages for the Drupal Starshot trial experience
Drupal CMS is the official name for Drupal Starshot. We officially have the Drupal CMS project on Drupal.org, where the previous prototype has been converted into the official codebase. This monolithic repository will contain the Composer project and packages (recipes) that makeup Drupal CMS.
Plasma Crash Course - KCrash
A while ago a colleague of mine asked about our crash infrastructure in Plasma and whether I could give some overview on it. This seems very useful to others as well, I thought. Here I am, telling you all about it!
Our crash infrastructure is comprised of a number of different components.
- KCrash: a KDE Framework performing crash interception and prepartion for handover to…
- coredumpd: a systemd component performing process core collection and handover to…
- DrKonqi: a GUI for crashes sending data to…
- Sentry: a web service and UI for tracing and presenting crashes for developers
We will look at them in turn. This post introduces KCrash.
KCrashKCrash, as the name suggests, is our KDE framework for crash handling. While it is a mid-tier framework and could be used by outside projects, it mostly doesn’t make sense to, because some behavior is very KDE-specific.
It installs POSIX signal handlers to intercept crash signals and then prepares the crashed process for handover to coredumpd and DrKonqi. More on these two in another post. Once prepared it sends the crash signal into the next higher level crash handler until the signal eventually reaches the default handler and cause the kernel to invoke the core pattern.
Before that can happen, a bunch of work needs doing inside KCrash. Most of it quite boring, but also somewhat challenging.
You see, when handling a signal you need to only use signal-safe functions. The manpage explains very well why. This proves quite challenging at the level we usually are at (i.e. Qt) because it is entirely unclear what is and isn’t ultimately signal-safe under the hood. Additionally, since we are dealing with crash scenarios, we must not trigger new memory allocation, because the heap management may have had an accident.
To that end, KCrash has to use fairy low-level API. To make that easier to work with, there are actually two parts to KCrash:
- The Initialization Stage
- The Crash Stage
Initialization is generally triggered by calling KCrash::initialize. You may already wonder what kind of initialization KCrash could possibly need. Well, the obvious one is setting up the signal handling. But beyond that the init stage is also used to prepare us for the crash stage. I’ve already mentioned the serious constraints we will encounter once the signal hits, so we had best be prepared for that. In particular we’ll do as much of the work as possible during initialization. This most important includes copying QString content into pre-allocated char * instances such that we later only need to read existing memory. The second most important aspect is the metadata file preparation for use in…
The Crash StageOnce initialization has happened, we are ready for crashes. Ideally the application doesn’t crash, of course. 😉
But if it does the biggest task is rescuing our data!
MetadataInside KCrash we have the concept of Metadata: everything we know about the crashed application: the signal, process ID, executable, used graphics device… and so on and so forth. All this data is collected into a metadata file on-disk in ~/.cache/kcrash-metadata at the time of crash.
Here’s an example file:
[KCrash] exe=/usr/bin/kwin_wayland glrenderer= platform=wayland appname=kwin_wayland apppath=/usr/bin signal=11 pid=1353 appversion=6.1.80 programname=KWin bugaddress=submit@bugs.kde.orgThe actual fields vary depending on what is available for any given application, but it’s generally more or less what is shown in the example.
This metadata file will later be consumed by DrKonqi in an effort to obtain information that only existed at runtime inside the application - such as the version that was running, or whether it was running in legacy X11 mode.
HandoffOnce the metadata is safely saved to disk, KCrash simply calls raise(). This re-raises the signal into the default handler, and through that causes a core dump.
What happens next is up to the system configuration as per the core manpage.
The recommended setup for distributions is that a crash handler be configured as core_pattern and that this handler consumes the crash. We recommend an implementation of the coredumpd and journald interfaces as that will then allow our crash handler to come in and log the crash with KDE.
So that was KCrash, the first in our four-step crash-handling pipeline. In the next blog post I’ll tell you all about the next one: coredumpd.
Real Python: Exploring Astrophysics in Python With pandas and Matplotlib
This course uses three problems often covered in introductory astro-physics courses to play in Python. Along the way you’ll learn some astronomy, and how to use a variety of datascience libraries like NumPy, Matplotlib, pandas, and pint.
In this video course you’ll learn about:
- Introductory astrophysics topics
- Working with dataframes in pandas
- Writing code that uses scientific units
- Visualizing information with Matplotlib
[ Improve Your Python With 🐍 Python Tricks 💌 – Get a short & sweet Python Trick delivered to your inbox every couple of days. >> Click here to learn more and see examples ]
Drupal Association blog: Extending the Life of Drupal 7 with Commercial Support
As a Drupal 7 user, you might feel the pressure of the impending end-of-life (EOL) announcement. While Drupal 7 has served us well over the years, preparing for the future is essential. However, The Drupal Association has partners who offer D7 Extended Security Support. you can confidently extend the life of your Drupal 7 site while strategically planning your migration to newer versions of Drupal. Find a partner here.
The Importance of Planning Your MigrationMigrating from Drupal 7 is crucial for staying current with new features, security updates, and performance improvements. There are significant advantages to moving to newer versions of Drupal:
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Enhanced Security: Newer versions of Drupal come with advanced security measures that protect your site from emerging threats.
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Modern Features: Newer Drupal versions introduce features that streamline content management, enhance user experience, and improve site performance.
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Better Performance: Newer versions are optimized for speed and efficiency, providing a better experience for your users.
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Community Support: With most of the Drupal community moving forward, staying on an outdated version might limit your access to community resources and modules.
To find a Drupal 7 Migration Partner to lead your migration, reach out to our Certified Migrations Partners that offer services in these categories.
Debian Brasil: Debian Day 2024 in Santa Maria - Brazil
by por Andrew Gonçalves
Debian Day in Santa Maria - RS 2024 was held after a 5-year hiatus from the previous version of the event. It took place on the morning of August 16, in the Blue Hall of the Franciscan University (UFN) with support from the Debian community and the Computing Practices Laboratory of UFN.
The event was attended by students from all semesters of the Computer Science, Digital Games and Informational Systems, where we had the opportunity to talk to the participants.
Around 60 students attended a lecture introducing them to Free and Open Source Software, Linux and were introduced to the Debian project, both about the philosophy of the project and how it works in practice and the opportunities that have opened up for participants by being part of Debian.
After the talk, a packaging demonstration was given by local DD Francisco Vilmar, who demonstrated in practice how software packaging works in Debian.
I would like to thank all the people who helped us:
- Debian Project
- Professor Ana Paula Canal (UFN)
- Professor Sylvio André Garcia (UFN)
- Laboratory of Computing Practices
- Francisco Vilmar (local DD)
And thanks to all the participants who attended this event asking intriguing questions and taking an interest in the world of Free Software.
Photos:
Debian Brasil: Debian Day 2024 em Santa Maria/RS - Brasil
por Andrew Gonçalves
O Debian Day em Santa Maria - RS 2024 foi realizado após 5 anos de hiato, foi feito durante a manhã do dia 16/08/2024 no Salão Azul da Universidade Franciscana (UFN) com apoio da comunidade Debian e do Laboratório de Práticas da Computação da UFN.
O evento contou com alunos de todos os semestres dos cursos de Ciência da Computação, Jogos Digitais e Sistemas de Informação, fizemos um coffee break onde tivemos a oportunidade de conversar com os participantes.
Cerca de 60 alunos prestigiaram uma palestra de introdução ao Software Livre e de Código Aberto, Linux e foram introduzidos ao projeto Debian, tanto sobre a filosofia do projeto, até como ele acontece na prática e oportunidades que se abriram para participantes do projeto por fazerem parte do Debian.
Após a palestra foi feita uma demonstração de empacotamento pelo DD local Francisco Vilmar, que demonstrou na prática como funciona o empacotamento de software no Debian.
Gostaria de agradecer a todas as pessoas que nos ajudaram:
- Projeto Debian
- Professora Ana Paula Canal (UFN)
- Professor Sylvio André Garcia
- Laboratório de Práticas da Computação
- Francisco Vilmar (DD local)
E um muito obrigado a todos os participantes que nos prestigiaram neste evento fazendo perguntas intrigantes e se interessando pelo mundo do Software Livre.
Algumas fotos:
Specbee: How to configure Faceted Search in Drupal - An easy step-by-step guide
The Drop Times: “It’s Time to Give Back Beyond Code”: Kevin Quillen
Python Bytes: #397 So many PyCon videos
CKEditor: DrupalCon 2024 - A chat with Simon Morvan
Dirk Eddelbuettel: digest 0.6.37 on CRAN: Maintenance
Release 0.6.37 of the digest package arrived at CRAN today and has also been uploaded to Debian.
digest creates hash digests of arbitrary R objects. It can use a number different hashing algorithms (md5, sha-1, sha-256, sha-512, crc32, xxhash32, xxhash64, murmur32, spookyhash, blake3,crc32c, xxh3_64 and xxh3_128), and enables easy comparison of (potentially large and nested) R language objects as it relies on the native serialization in R. It is a mature and widely-used package (with 70.8 million downloads just on the partial cloud mirrors of CRAN which keep logs) as many tasks may involve caching of objects for which it provides convenient general-purpose hash key generation to quickly identify the various objects.
This release updates one of the different hashing source functions which, to remain close to their upstream, used Free() and Calloc() (uppercased to use the R allocator) but not the prefixed stricter versions R_Free() and R_Calloc(). R will switch to enforcing these in the next release next year. Kevin had noticed (while doing some other testing) that this now fails under R-devel (with a switch set), and prepares a very nice and clean PR to take care of it. As of today, CRAN is now sending ‘please fix, or else …’ notes so it was a good time to send this to CRAN. We also updated some remaining http URLs in the README.md to https, and switched to Author/Maintainer field to the now also mandatory Authors@R.
My CRANberries provides a summary of changes to the previous version. For questions or comments use the issue tracker off the GitHub repo. For documentation (including the changelog) see the documentation site.
If you like this or other open-source work I do, you can now sponsor me at GitHub.
This post by Dirk Eddelbuettel originated on his Thinking inside the box blog. Please report excessive re-aggregation in third-party for-profit settings.
TestDriven.io: Limiting Content Types in a Django Model
Message-passing APIs (SIMPL)
In the KDE world, famously there was that weekend where DCOP (Desktop Communicating Objects Protocol) was created, setting the stage for things like KParts. GNOME picked the CORBA object model, and much later the Free Desktop world settled on DBus as a message-passing API. But even at the time, there were other message-passing APIs. At work-work I use one, called SIMPL, which is kind of shout-out to the late ’90s of DCOP.
Please note that my presentation of “history” is just what I remember now of events that were already “tales told ‘round the campfire” 15 years ago. Corrections welcome (by email).
At work-work SIMPL is just a given, and it’s got wrappers and abstractions so that there’s a decent C++ style API around it. At its heart it is a point-to-point message-passing API with no policy at all about the payload of messages. That is both a blessing – no policy means it can be used for whatever kind of messages you think is necessary – and a curse – no policy means that you end up writing a bunch of abstractions to represent the messages that you actually use.
Code at the wrapped-in-C++ level looks something like this (effectively obscuring the underlying transport):
auto reply = CoordinatorTask().Send(requests::GetCurrentUser()); if(reply.has_value()) { do_something(reply.value().username); ...There does not seem to be much online about SIMPL anymore. There is a LinuxDevices article from 2000 when SIMPL was under some active development as an Open Source project, there’s a LWN comment from 2015 that mentions it still, and there’s a Wikipedia article on it, as a historical note. Note that the Website link on wikipedia goes to something that is now a spam domain. I can’t quickly find sources anymore.
I do wonder at the chances of history that made desktop developers at the time entirely miss out on this existing message-passing mechanism – perhaps the SIMPL authors were too focused on industrial automation and not visible in the X11 desktop space, and not visible on SunOS and other platforms where a fair bit of KDE development happened at the time.
One thing that the SIMPL library developers emphasize repeatedly in documentation (there’s a book) is a philosophy of doing one thing and doing it well. So serialization and message payloads are not part of this – no policy. So security and access control are not part of his – no policy. Those concerns are things that can go into a different API layer on top of SIMPL.
Something else that the SIMPL authors emphasize is doing one thing and doing it well. That applies to the applications that use SIMPL, in particular. And that translates, in the depths of the library, to being able to register only one name for an application (for purposes of discovering what other applications there are, each application has a unique name in the system). It translates into a lack of thread safety, due to the use of global state. It translates into a contextless API, so all an application can do is call “give me the next incoming message”. There’s no concept of an event-loop, and no obvious mechanisms for integrating SIMPL message-handling into another event loop (like an X11 loop).
For me personally this means that I need to re-tool my brain during the trip between home and work, switching of Qt wrappers around DBus to work-work wrappers around SIMPL and the subtleties of each. In practice, that means mostly cursing QtDBus (because of the relative amount of time I put into both).
Matthew Garrett: Client-side filtering of private data is a bad idea
Feeld is a dating app aimed largely at alternative relationship communities (think "classier Fetlife" for the most part), so unsurprisingly it's fairly popular in San Francisco. Their website makes the claim:
Can people see what or who I'm looking for?
No. You're the only person who can see which genders or sexualities you're looking for. Your curiosity and privacy are always protected.
which is based on you being able to restrict searches to people of specific genders, sexualities, or relationship situations. This sort of claim is one of those things that just sits in the back of my head worrying me, so I checked it out.
First step was to grab a copy of the Android APK (there are multiple sites that scrape them from the Play Store) and run it through apk-mitm - Android apps by default don't trust any additional certificates in the device certificate store, and also frequently implement certificate pinning. apk-mitm pulls apart the apk, looks for known http libraries, disables pinning, and sets the appropriate manifest options for the app to trust additional certificates. Then I set up mitmproxy, installed the cert on a test phone, and installed the app. Now I was ready to start.
What became immediately clear was that the app was using graphql to query. What was a little more surprising is that it appears to have been implemented such that there's no server state - when browsing profiles, the client requests a batch of profiles along with a list of profiles that the client has already seen. This has the advantage that the server doesn't need to keep track of a session, but also means that queries just keep getting larger and larger the more you swipe. I'm not a web developer, I have absolutely no idea what the tradeoffs are here, so I point this out as a point of interest rather than anything else.
Anyway. For people unfamiliar with graphql, it's basically a way to query a database and define the set of fields you want returned. Let's take the example of requesting a user's profile. You'd provide the profile ID in question, and request their bio, age, rough distance, status, photos, and other bits of data that the client should show. So far so good. But what happens if we request other data?
graphql supports introspection to request a copy of the database schema, but this feature is optional and was disabled in this case. Could I find this data anywhere else? Pulling apart the apk revealed that it's a React Native app, so effectively a framework for allowing writing of native apps in Javascript. Sometimes you'll be lucky and find the actual Javascript source there, but these days it's more common to find Hermes blobs. Fortunately hermes-dec exists and does a decent job of recovering something that approximates the original input, and from this I was able to find various lists of database fields.
So, remember that original FAQ statement, that your desires would never be shown to anyone else? One of the fields mentioned in the app was "lookingFor", a field that wasn't present in the default profile query. What happens if we perform the incredibly complicated hack of exporting a profile query as a curl statement, add "lookingFor" into the set of requested fields, and run it?
Oops.
So, point 1 is that you can't simply protect data by having your client not ask for it - private data must never be released. But there was a whole separate class of issue that was an even more obvious issue.
Looking more closely at the profile data returned, I noticed that there were fields there that weren't being displayed in the UI. Those included things like "ageRange", the range of ages that the profile owner was interested in, and also whether the profile owner had already "liked" or "disliked" your profile (which means a bunch of the profiles you see may already have turned you down, but the app simply didn't show that). This isn't ideal, but what was more concerning was that profiles that were flagged as hidden were still being sent to the app and then just not displayed to the user. Another example of this is that the app supports associating your profile with profiles belonging to partners - if one of those profiles was then hidden, the app would stop showing the partnership, but was still providing the profile ID in the query response and querying that ID would still show the hidden profile contents.
Reporting this was inconvenient. There was no security contact listed on the website or in the app. I ended up finding Feeld's head of trust and safety on Linkedin, paying for a month of Linkedin Pro, and messaging them that way. I was then directed towards a HackerOne program with a link to terms and conditions that 404ed, and it took a while to convince them I was uninterested in signing up to a program without explicit terms and conditions. Finally I was just asked to email security@, and successfully got in touch. I heard nothing back, but after prompting was told that the issues were fixed - I then looked some more, found another example of the same sort of issue, and eventually that was fixed as well. I've now been informed that work has been done to ensure that this entire class of issue has been dealt with, but I haven't done any significant amount of work to ensure that that's the case.
You can't trust clients. You can't give them information and assume they'll never show it to anyone. You can't put private data in a database with no additional acls and just rely on nobody ever asking for it. You also can't find a single instance of this sort of issue and fix it without verifying that there aren't other examples of the same class. I'm glad that Feeld engaged with me earnestly and fixed these issues, and I really do hope that this has altered their development model such that it's not something that comes up again in future.
(Edit to add: as far as I can tell, pictures tagged as "private" which are only supposed to be visible if there's a match were appropriately protected, and while there is a "location" field that contains latitude and longitude this appears to only return 0 rather than leaking precise location. I also saw no evidence that email addresses, real names, or any billing data was leaked in any way)
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FSF Events: Free Software Directory meeting on IRC: Friday, August 23, starting at 12:00 EDT (16:00 UTC)
The Drop Times: A Name of Purpose and Clarity
Real Python: Python Classes: The Power of Object-Oriented Programming
Python supports the object-oriented programming paradigm through classes. They provide an elegant way to define reusable pieces of code that encapsulate data and behavior in a single entity. With classes, you can quickly and intuitively model real-world objects and solve complex problems.
If you’re new to classes, need to refresh your knowledge, or want to dive deeper into them, then this tutorial is for you!
In this tutorial, you’ll learn how to:
- Define Python classes with the class keyword
- Add state to your classes with class and instance attributes
- Provide behavior to your classes with methods
- Use inheritance to build hierarchies of classes
- Provide interfaces with abstract classes
To get the most out of this tutorial, you should know about Python variables, data types, and functions. Some experience with object-oriented programming (OOP) is also a plus. Don’t worry if you’re not an OOP expert yet. In this tutorial, you’ll learn the key concepts that you need to get started and more. You’ll also write several practical examples to help reinforce your knowledge of Python classes.
Get Your Code: Click here to download your free sample code that shows you how to build powerful object blueprints with classes in Python.
Take the Quiz: Test your knowledge with our interactive “Python Classes - The Power of Object-Oriented Programming” quiz. You’ll receive a score upon completion to help you track your learning progress:
Interactive Quiz
Python Classes - The Power of Object-Oriented ProgrammingIn this quiz, you'll test your understanding of Python classes. With this knowledge, you'll be able to define reusable pieces of code that encapsulate data and behavior in a single entity, model real-world objects, and solve complex problems.
Getting Started With Python ClassesPython is a multiparadigm programming language that supports object-oriented programming (OOP) through classes that you can define with the class keyword. You can think of a class as a piece of code that specifies the data and behavior that represent and model a particular type of object.
What is a class in Python? A common analogy is that a class is like the blueprint for a house. You can use the blueprint to create several houses and even a complete neighborhood. Each concrete house is an object or instance that’s derived from the blueprint.
Each instance can have its own properties, such as color, owner, and interior design. These properties carry what’s commonly known as the object’s state. Instances can also have different behaviors, such as locking the doors and windows, opening the garage door, turning the lights on and off, watering the garden, and more.
In OOP, you commonly use the term attributes to refer to the properties or data associated with a specific object of a given class. In Python, attributes are variables defined inside a class with the purpose of storing all the required data for the class to work.
Similarly, you’ll use the term methods to refer to the different behaviors that objects will show. Methods are functions that you define within a class. These functions typically operate on or with the attributes of the underlying instance or class. Attributes and methods are collectively referred to as members of a class or object.
You can write classes to model the real world. These classes will help you better organize your code and solve complex programming problems.
For example, you can use classes to create objects that emulate people, animals, vehicles, books, buildings, cars, or other objects. You can also model virtual objects, such as a web server, directory tree, chatbot, file manager, and more.
Finally, you can use classes to build class hierarchies. This way, you’ll promote code reuse and remove repetition throughout your codebase.
In this tutorial, you’ll learn a lot about classes and all the cool things that you can do with them. To kick things off, you’ll start by defining your first class in Python. Then you’ll dive into other topics related to instances, attributes, and methods.
Defining a Class in PythonTo define a class, you need to use the class keyword followed by the class name and a colon, just like you’d do for other compound statements in Python. Then you must define the class body, which will start at the next indentation level:
Python Syntax class ClassName: <body> Copied!In a class’s body, you can define attributes and methods as needed. As you already learned, attributes are variables that hold the class data, while methods are functions that provide behavior and typically act on the class data.
Note: In Python, the body of a given class works as a namespace where attributes and methods live. You can only access those attributes and methods through the class or its objects.
As an example of how to define attributes and methods, say that you need a Circle class to model different circles in a drawing application. Initially, your class will have a single attribute to hold the radius. It’ll also have a method to calculate the circle’s area:
Python circle.py import math class Circle: def __init__(self, radius): self.radius = radius def calculate_area(self): return math.pi * self.radius ** 2 Copied!In this code snippet, you define Circle using the class keyword. Inside the class, you write two methods. The .__init__() method has a special meaning in Python classes. This method is known as the object initializer because it defines and sets the initial values for the object’s attributes. You’ll learn more about this method in the Instance Attributes section.
Read the full article at https://realpython.com/python-classes/ »[ Improve Your Python With 🐍 Python Tricks 💌 – Get a short & sweet Python Trick delivered to your inbox every couple of days. >> Click here to learn more and see examples ]