Linux

Running “java -jar YOURjarfile.jar” will of course start a jar on your linux machine, but it will stop running once you disconnect your ssh session for instance. So you do need to run your jar file in the background. Pierre Janineh described a way to achieve this goal: %[https://medium.com/programming-with-pierre/start-a-java-service-from-jar-on-an-ubuntu-instance-40dff8acc4a5] Another approach is obviously to run your jar “as a service” via systemd. If you ensure that this service will auto restart in case of a failure or after reboot, you Java application will again restart magically and automatically. ...

In almost every programming language, you can quickly run into problems that the app establishes connections but never closes them. Some programming languages ​​” automatically” close unused connections, and this sometimes works better, sometimes worse. It is good practice to monitor if the “promises” of the vendors do work. Such open connections (I/O, databases, net/HTTP requests, etc.) accumulate over time until there are no more free connections. Boom, in simple words: the app stopped working. The annoying thing is that the app may not crash (depending on your error handling!), it just often can’t establish new connections and doesn’t work as expected. ...

As a developer, you often face the challenge of having to generate or integrate an avatar image, e.g., for the profile. There are several ways to do this: You can offer the user an upload option and then save the profile picture. A user’s email can be matched against services such as gravatar.com. It is checked whether a profile picture is stored in the authentication service used. However, if the user does not want to upload a picture, or no picture can be assigned to the user online, it is now expected that the profile picture will be replaced by a placeholder with the initials. Here we have 2 options: ...

Now that you have built your secure Linux Server for Xojo Web 2, you might run into issues around 90 days latest! Introduction Why? Because your certificates will expire. We installed let’s encrypt free of cost certificates. They are a tremendous relief, but they need renewal every 89 days latest. On a side note: I got some replies that I’m not profoundly diving into the certificate’s topic or how to use an editor on Linux (yes, “vim” is not the easiest one — try “nano” for instance). The above article proved to work for a couple of people without any issues, which was the purpose. Of course, you have to do your homework, and for a deep dive into some topics, you have to learn those skills. ...

What is fail2ban all about? Fail2ban determines the IP addresses in the server’s log files that are noticeable due to unusual behaviour, such as repeatedly trying to log in with an incorrect password. When a certain number of unsuccessful attempts happened, fail2ban will automatically ensure that the IP address is banned or blocked for a predetermined time. The administrator can also configure Fail2ban so that a suspicious IP address is first reported to him by email. You have many options here. ...

With Xojo Web 2, it becomes relatively easy to set up a Server and run your first App. You would not even need your own webserver as a Xojo Web 2 App has built-in its own. But in today’s world, running a Web app is one thing; running it securely is a different story. This beginner’s guide aims to enable you to run your first App in no time. What we will achieve in this tutorial: ...

Well, there are many reasons why it is cool having the possibility to connect remotely to another server. You’ll need such an option for a secure connection to your remote server to upload files and make changes on your server. But perhaps you are running a remote Database on an external server, and then again, an SSH connection is a must (at least if you want to run things securely). ...