This article describes how to develop a real-time weather prediction app in Flutter using the Tomorrow.io Weather API. The app consists of a single screen that displays the current weather and a 4-day daily forecast for a specific location. We’re creating this prediction app on Flutter because it is an open-source UI development kit, which means it can be integrated beautifully into desktop and mobile apps across various platforms, making it scalable. 

Once a upon a time I moved to brand new project. And without much thought, I decided to take DevOps responsibilities (after a long period of Frontend). Huge mono-repository (Angular and Node.js) gives rise to many specific problems. And this project was no exception. At the very beginning CI/CD duration was about 1.5h. And that was the biggest problem to take care of.

But at first, I want to talk about "Bourne again shell", cause CI/CD automation almost entirely was implemented by means of shell scripts (Bash). In context of huge mono-repo even regular build becomes a piece of odd stuff. That`s why a huge amount of scripts with complicated logic inside (build, test, deploy, generation of release notes, collection of logs and metrics, ...) was another significant problem.

Regardless of lang, quality of complex logic should be under control. It is no secret that key aspect of code quality control - is tests. For example, to refactor safely major logic should be covered with tests. We decided to keep shell scripts untouched and cover the major ones with tests before any refactoring. Of course, it is possible to use Jest (or Mocha) with a bunch of awful utils to test shell scripts. This approach is a bit wordy and has no value if scripts under test is written in Bash. Also I have no idea how to mock external shell commands (such as curl, ls, touch, npm, ...) with Jest or similar framework.

After Epic released the UE5 technology demo at the beginning of 2021, the discussion about UE5 has never stopped. Related technical discussions mainly centered on two new features: global illumination technology Lumen and extremely high model detail technology Nanite. There have been some articles [1 ][2] analyzing Nanite technology in more detail. This article mainly starts from the RenderDoc analysis and source code of UE5, combined with some existing technical data, aims to provide an intuitive and overview understanding of Nanite, and clarify its algorithm principles and design ideas, without involving too many source code level Implementation details.

Overview

Sometimes all of us need to make a graphical installer for one's own linux distro. It goes without saying that you are able to use a distro-specific installer like Anaconda for RedHat-based or DebianInstaller for debian-based. On the other hand Calamares is a graphical installer which is not aligned with only one package manager.

I want to share my experience how to make a universal install solution with GUI. I did not find any complete article about it, hence, I reinvented the wheel.

Lumen is UE5’s GI system, it is different from the traditional real-time GI which only includes the contribution of indirect diffuse reflection. It also includes indirect diffuse reflection and indirect highlight, providing a new set of complete indirect lighting. Lumen supports both hardware-based RTX and software-based Trace algorithms. The starting point of this article is that Lumen GI uses the process, algorithm, and data structure analysis of indirect diffuse reflection part based on software Trace to understand the basic principle and operation mechanism of Lumen from a macro perspective.

The core of Lumen includes the following parts:

Somehow I saw code in the project of a neighboring team that generated a string with URL parameters for subsequent insertion into the iframesrc attribute.

This article may seem superfluous, obvious or too simple, but since this occurs in wildlife, you should not be silent about it, but rather share best-practices.

Today, we will share some knowledge points related to resource memory leak. A memory leak is the most common issue that we continuously see and also are afraid of. What is the reason behind it? Because we can’t predict the extent of the leak before we locate the leak bottleneck, we had no idea whether it will burst out at a certain moment on the line. We have received feedback from developers that their players had no problem playing for half an hour, but they would get more and more stuck after 3 to 4 hours of playing, which they never expected before. How can it be solved? Today’s sharing will answer such questions.

UWA’s GOT Online-Assets report has a resource occupancy trend chart. If there is a rising trend like the one below, you must pay special attention.

The Real-Time Clock (RTC) Calendar Registers in STM32 microcontrollers implemented in Binary Code Decimal format (BCD) i. e., every two digits are represented by one byte (low digit in 0-3 bits and high digit 4-7 bits). At least there are 5 bytes required to store date and time data in a such format. There are cases when memory allocation for time stamp might become critical, e. g., the events log keeping in an extern non-volatile memory IC. Here the memory value for a single event (event serial number, timestamp, event parameters, and its CRC) is fixed and can compose up to 16 bytes. The maximum quantity of the events increasing, and time spent on a single operation reducing (for reserved power sources as supercapacitors and electrolytic capacitors is critical) can be achieved with less memory amount required for the event field.

The spread of cryptocurrencies contributed to the development of many solutions based on a distributed ledger technology (blockchain). Although the scope of these solutions varies, most of them have the same basic set of security services, i.e. confidentiality, authenticity, and integrity. These features are granted by the practical applications of public key cryptography, in particular,  digital signature (DS). But unlike many other applications of public key cryptography, cryptocurrency networks do not use public key certificates. This is the aspect that we would like to talk about.

In the last article we reviewed the stages of query execution. Before we move on to plan node operations (data access and join methods), let's discuss the bread and butter of the cost optimizer: statistics.

Dive in to learn what types of statistics PostgreSQL collects when planning queries, and how they improve query cost assessment and execution times.

This is the first in series of articles dedicated to detailed overview of processes and components of enterprise identity and access management (IAM). These articles are designed to help technical architects and system designers to better understand what is involved in complex business processes which drive identity management and provide detailed review of all critical components.

Solid understanding of identity management business processes before implementation of a new IAM system very often makes a difference between success and failure and it must be worked out and agreed to by all key participant before implementation can start.

This review does not address specific software configurations and settings required to support these processes and workflow, but any modern identity management software will be able to support them.

Diagram below documents workflow for an employee on-boarding which is one of the core identity management processes to support new employee who is joining the company. The flow is designed to be integrated into existing hiring process and provide logical and physical access to an employee by day one of the employment.

If you regularly use a static code analyzer, you can save time on guessing why the new code doesn't work as planned. Let's look at another interesting error — the function broke during refactoring, and no one noticed that. No one — except for PVS-Studio that can automatically scan the project and email the report to us.

In the green energy field, the solar panels composed of bendable solar cells tend to significantly increase in popularity last time. The difficulty during the designing of the different devices (such as solar chargers, MPPT-controllers) emerges because of the strong lack of technical information about this kind of solar cell.  

In this article, the equivalent scheme of the bendable solar produced by the Sunpower company - Maxeon gen 5 and its coarse simulation model is proposed.

You decided to make an app that works with SVG. Encouraged by the enthusiasm, you collected libraries and successfully made the application. But suddenly you find that the app is sending strange network requests. And data is leaking from the host-machine. How so?

Let's continue with a series of small notes illustrating the PVS-Studio's ability to quickly find new errors in the code. If the analyzer is regularly used, of course :). Today we have another bug in the Blender project.

This is the translation of my article about ECS. Original (in Russian).

ECS (Entity Component System) is an architectural pattern used in game development.

In this article, I am going to describe some of the general principles of ECS frameworks' inner workings and some of the problems I have faced during the development of my own.

When I first started learning about ECS everything seemed wonderful, but only in theory. I needed some real practice to make sure that all that they were saying about ECS was true.

I’ve tried different frameworks with different engines and programming languages. Mostly it was the gorgeous EnTT framework that I used with the Godot engine and LeoECS with Unity. I haven’t tried Unity’s native ECS from DOTS because it was rather unpolished at the time I was starting.

After a while, I got enough practical experience with ECS but it was still unclear to me how all this magic works under the hood. There are a few good blogs about ECS development (https://skypjack.github.io/ from the author of EnTT and https://ajmmertens.medium.com/ from the author of Flecs) but none of them gave me enough understanding about how they are implemented. So eventually, following Bender’s example, I decided that I’m gonna make my own ECS =)

We are often asked whether we send bug reports to developers of open-source projects. The answer is yes. More than that— we sometimes track the progress. This article is about one of the cases when this habit prevented a sloppy bug fix.

Seems like Microsoft has just announced Visual Studio 2022. And it already came out! For us at PVS-Studio, this meant only one thing — we must support this IDE in the next PVS-Studio release. Almost everything went smoothly. However, there were some hitches that we're going to discuss today.

We are pleased to announce the first release of PVS-Studio in 2022. In this article, we discuss various enhancements in managing Unreal Engine and ASP.NET Core projects. Keep reading to learn about new diagnostics and latest articles by PVS-Studio.

How can simple XML files processing turn into a security weakness? How can a blog deployed on your machine cause a data leak? Today we'll find answers to these questions, learn what XXE is and how it looks like.