In an earlier post I complained about spreadsheet programs: Excel, LibreOffice Calc and Gnumeric. All of them confuse non-dates with dates, and automatically interpret certain number strings with 2 colons as [h]:mm:ss. Grrr.

Many tools for network analysis have existed for quite some time. Under Linux, for example, these are Wireshark, tcpdump, nload, iftop, iptraf, nethogs, bmon, tcptrack as well as speedometer and ettercap. For a detailed description of them, you may have a look at Silver Moon’s comparison [1].

So, why not use an existing tool, and write your own one, instead? Reasons I see are a better understanding of TCP/IP network protocols, learning how to code properly, or implementing just the specific feature you need for your use case because the existing tools do not give you what you actually need. Furthermore, speed and load improvements to your application/system can also play a role that motivates you to move more in this direction.

In the wild, there exist quite several Python libraries for network processing and analysis. For low-level programming, the socket library [2] is the key. High-level protocol-based libraries are httplib, ftplib, imaplib, and smtplib. In order to monitor network ports and the packet stream competitive candidates, are python-nmap [3], dpkt [4], and PyShark [5] are used. For both monitoring and changing the packet stream, the scapy library [6] is widely in use.

In this article, we will have a look at the PyShark library and monitor which packages arrive at a specific network interface. As you will see below, working with PyShark is straightforward. The documentation on the project website will help you for the first steps — with it, you will achieve a usable result very quickly. However, when it comes to the nitty-gritty, more knowledge is necessary.

PyShark can do a lot more than it seems at first sight, and unfortunately, at the time of this writing, the existing documentation does not cover that in full. This makes it unnecessarily difficult and provides a good reason to look deeper under the bonnet.

What is a role? Put simply, roles are a form of code reuse. Often, the term shared behavior is used. Roles are said to be consumed and the methods ( including attribute accessors ) are flattened into the consuming class.

One of the major benefits of roles is they attempt to solve the diamond problem encountered in multi-inheritance by requiring developers to resolve name collisions manually that arise in multi-inheritance. Don't be fooled however, roles are a form of multi-inheritance.

I often see roles being used in ways they shouldn’t be. Let’s look at the mis-use of roles, then see an example of shared behavior.

I’m using that word inheritance a lot for a reason, one of the two ways I see roles most often misused is to hide an inheritance nightmare.

"Look ma, no multi-inheritance support, no problem. I’ll just throw stuff in roles and glum them on wherever I really want to use inheritance. It all sounds fancy, but I am just lumping stuff into a class cause I don’t really understand OO principals."

Software developers are highly sought-after tech professionals, and the demand for their skills is continually increasing. In this Life in Tech article, we’ll provide a general look at the various duties and requirements associated with the role of software developer.

Let’s start with a basic description before getting into the nuances and specifics. Briefly, then, software developers conceive, design, and build computer programs, says ComputerScience.org. To accomplish this, they identify user needs, write and test new software, and maintain and improve it as needed. Software developers occupy crucial roles in a variety of industries, including tech, entertainment, manufacturing, finance, and government.

How do others program? I realized today that I've never actually seen it; in more than 30 years of coding, I've never really watched someone else write nontrivial code over a long period of time. I only see people's finished patches—and I know that the patches I send out for review sure doesn't look much like the code I initially wrote. (There are exceptions for small bugfixes and the likes, of course.)

Over the years, I found myself multiple times using Gonum Plot. I do find it as a very good and easy to use plotting tool for Go.

The problem I found myself, over and over, dealing with is the tickers scale. If you know before-hand the values that can be expected to be created by the application, it is very straightforward, but the majority of times, this is not the case. I often find myself creating a plotting application on data that track events that have not yet happened and cannot predict their range.

To solve the issue, I create a package that has a struct that implements the Ticker interface and provides tickers that are usually sensible. Since this struct only works for integer scales, I called it sit, which stands for “Sensible Int Ticks”.

It's pretty safe to say that most of the modern web would not exist without JavaScript. It's one of the three standard web technologies (along with HTML and CSS) and allows anyone to create much of the interactive, dynamic content we have come to expect in our experiences with the World Wide Web. From frameworks like React to data visualization libraries like D3, it's hard to imagine the web without it.

There's a lot to learn, and a great way to begin learning this popular language is by writing a simple application to become familiar with some concepts. Recently, some Opensource.com correspondents have written about how to learn their favorite language by writing a simple guessing game, so that's a great place to start!

As was previously discussed, since the 6.0.0 release of Qt, Qt 3D no longer ships as a pre-compiled module. If you need to use it on your projects, try out the new features, or just see your existing application is ready for the next chapter of Qt’s life, you need to compile Qt 3D from source.

In order to do this, you can do it the traditional way ([cq]make ...; make; make install) or use the Conan-based system that is being pioneered with the latest version of the MaintenanceTool.

Several readers have expressed concerned that Qt open-source downloads have disappeared but The Qt Company has now commented it's only a temporary issue due to a "severe hardware failure" in the cloud.

Qt's open-source online installer and offline packages are not currently working for the open-source options but the commercial downloads are working. While that may raise concerns given Qt's increasing commercial focus, The Qt Company posted to their blog that this interruption around open-source package downloads is due to a reported major hardware problem at their cloud provider.

Fortunally, the Qt API provides multiple ways to implement custom shapes, that depending on the needs might be enough.

There is the Canvas API using the same API as the canvas API on the web but in QML. It’s easy to use but very slow and I wouldn’t recommend it.

Instead of the Canvas API, from the QML side, there is the QtQuick Shapes module. This module allows creating more complex shapes directly from the QML with a straightforward declarative API. In many cases, this is good enough for the application developer but this module doesn’t offer a public C++ API.

If you need more controls, using C++ will be required to implement custom QQuickItem. Unfortunately drawing on the GPU using QQuickItem is more complex than the QPainter API. You can’t just use commands like drawRect, but will need to convert all your shapes in triangles first. This involves a lot of maths like it can be seen in the example from the official documentation or from the KDAB tutorial (Efficient custom shapes in Qt Quick).

A QPainer way is also available with QQuickPaintedItem, but it is slow because it renders your shape in a textured rectangle in the Scene Graph.

Recently, there have been a lot of improvements in rustdoc. It was possible thanks to our new contributors. In light of these recent contributions, a few changes were made in the rustdoc team.

@jyn514 noticed a while ago that most of the work in Rustdoc is duplicated: there are actually three different abstract syntax trees (ASTs)! One for doctree, one for clean, and one is the original HIR used by the compiler. Rustdoc was spending quite a lot of time converting between them. Most of the speed improvements have come from getting rid of parts of the AST altogether.

The Optional object type in Java was introduced with version 8 of Java. It is used when we want to express that a value might not be known (yet) or it’s not applicable at this moment. Before Java 8 developers might have been tempted to return a null value in this case.

Oracle on Tuesday released GraalVM 21.0 as the latest version of their Java VM/JDK that also supports other languages and modes of execution.

One of the notable additions with GraalVM 21.0 is supporting Java on Truffle, as an example JVM implementation using the Truffle interpreter. GraalVM's Truffle framework is an open-source library for writing programming language interpreters. With Java on Truffle, it's of the same nature as the likes of JavaScript, Ruby, Python, and R within the GraalVM ecosystem. Java on Truffle allows for improved isolation from the host JVM, run Java bytecode in a separate context from the JVM, running in the context of a native image but with dynamically loaded bytecode allowed, and other Truffle framework features. More details about the Java on Truffle implementation via the GraalVM manual.