Tag: mobile

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Connect Fedora to your Android phone with GSConnect

Both Apple and Microsoft offer varying levels of integration of their desktop offerings with your mobile devices. Fedora offers a similar if not greater degree of integration with GSConnect. It lets you pair your Android phone with your Fedora desktop and opens up a lot of possibilities. Keep reading to discover more about what it is and how it works.

What is GSConnect?

GSConnect is an implementation of the KDE Connect project tailored for the GNOME desktop. KDE Connect makes it possible for your devices to communicate with each other. However, installing it on Fedora’s default GNOME desktop requires pulling in a large number of KDE dependencies.

GSConnect is a complete implementation of KDE Connect, but in the form of a GNOME shell extension. Once installed, GSConnect lets you do the following and a lot more:

  • Receive phone notifications on your desktop and reply to messages
  • Use your phone as a remote control for your desktop
  • Share files and links between devices
  • Check your phone’s battery level from the desktop
  • Ring your phone to help find it

Setting up the GSConnect extension

Setting up GSConnect requires installing two components: the GSConnect extension on your desktop and the KDE Connect app on your Android device.

First, install the GSConnect extension from the GNOME Shell extensions website: GSConnect. (Fedora Magazine has a handy article on How to install a GNOME Shell extension to help you with this step.)

The KDE Connect app is available on Google’s Play Store. It’s also available on the FOSS Android apps repository, F-Droid.

Once you have installed both these components, you can pair your two devices. Installing the extension makes it show up in your system menu as Mobile Devices. Clicking on it displays a drop down menu, from which you can access Mobile Settings.

GSConnect menu within system menu

Here’s where you can view your paired devices and manage the features offered by GSConnect. Once you are on this screen, launch the app on your Android device.

You can initiate pairing from either device, but here you’ll be connecting to your desktop from the Android device. Simply hit refresh on the app, and as long as both devices are on the same wireless network, your desktop shows up in your Android device. You can now send a pair request to the desktop. Accept the pair request on your desktop to complete the pairing.

Pair request from Android app to desktop

Using GSConnect

Once paired, you’ll need to grant permissions on your Android device to make use of the many features available on GSConnect. Click on the paired device in the list of devices to see all available functions and enable or disable them according to your preferences.

GSConnect device preferences

Remember that you’ll also need to grant corresponding permissions in the Android app to be able to use these functions. Depending upon the features you’ve enabled and the permissions you’ve granted, you can now access your mobile contacts on your desktop, get notified of messages and reply to them, and even sync the desktop and Android device clipboards.

Integration with Files and your web browsers

GSConnect allows you to directly send files to your Android device from your desktop file explorer’s context menu.

On Fedora’s default GNOME desktop, you will need to install the nautilus-python package in order to make your paired devices show up in the context menu. Installing this is as straightforward as running the following command from your preferred terminal:

$ sudo dnf install nautilus-python

Once done, the Send to Mobile Device entry appears in the context menu of the Files app.

Context menu entry to send file to mobile device

Similarly, install the corresponding WebExtension for your browser, be it Firefox or Chrome, to send links to your Android device. You have the option to send the link to launch directly in your browser or to deliver it as SMS.

Running Commands

GSConnect lets you define commands which you can then run on your desktop, from your remote device. This allows you to do things such as take a screenshot of your desktop, or lock and unlock your desktop from your Android device, remotely.

Define commands to be run from the mobile device, on the desktop

To make use of this feature, you can use standard shell commands and the CLI exposed by GSConnect. Documentation on this is provided in the project’s GitHub repository: CLI Scripting.

The KDE UserBase Wiki has a list of example commands. These examples cover controlling the brightness and volume on your desktop, locking the mouse and keyboard, and even changing the desktop theme. Some of the commands are specific for KDE Plasma, and modifications are necessary to make it run on the GNOME desktop.

Explore and have fun

GSConnect makes it possible to enjoy a great degree of convenience and comfort. Dive into the preferences to see all that you can do and get creative with the commands function. Feel free to share all the possibilities this utility unlocked in your workflow in the comments below.

Photo by Pathum Danthanarayana on Unsplash.

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Develop GUI apps using Flutter on Fedora

When it comes to app development frameworks, Flutter is the latest and greatest. Google seems to be planning to take over the entire GUI app development world with Flutter, starting with mobile devices, which are already perfectly supported. Flutter allows you to develop cross-platform GUI apps for multiple targets — mobile, web, and desktop — from a single codebase.

This post will go through how to install the Flutter SDK and tools on Fedora, as well as how to use them both for mobile development and web/desktop development.

Installing Flutter and Android SDKs on Fedora

To get started building apps with Flutter, you need to install

  • the Android SDK;
  • the Flutter SDK itself; and,
  • optionally, an IDE and its Flutter plugins.

Installing the Android SDK

Flutter requires the installation of the Android SDK with the entire Android Studio suite of tools. Google provides a tar.gz archive. The Android Studio executable can be found in the android-studio/bin directory and is called studio.sh. To run it, open a terminal, cd into the aforementioned directory, and then run:

$ ./studio.sh

Installing the Flutter SDK

Before you install Flutter you may want to consider what release channel you want to be on.

The stable channel is least likely to give you a headache if you just want to build a mobile app using mainstream Flutter features.

On the other hand, you may want to use the latest features, especially for desktop and web app development. In that case, you might be better off installing either the latest version of the beta or even the dev channel.

Either way, you can switch between channels after you install using the flutter channel command explained later in the article.

Head over to the official SDK archive page and download the latest installation bundle for the release channel most appropriate for your use case.

The installation bundle is simply a xz-compressed tarball (.tar.xz extension). You can extract it wherever you want, given that you add the flutter/bin subdirectory to the PATH environment variable.

Installing the IDE plugins

To install the plugin for Visual Studio Code, you need to search for Flutter in the Extensions tab. Installing it will also install the Dart plugin.

The same will happen when you install the plugin for Android Studio by opening the Settings, then the Plugins tab and installing the Flutter plugin.

Using the Flutter and Android CLI Tools on Fedora

Now that you’ve installed Flutter, here’s how to use the CLI tool.

Upgrading and Maintaining Your Flutter Installations

The flutter doctor command is used to check whether your installation and related tools are complete and don’t require any further action.

For example, the output you may get from flutter doctor right after installing on Fedora is:

Doctor summary (to see all details, run flutter doctor -v): [✓] Flutter (Channel stable, v1.12.13+hotfix.5, on Linux, locale it_IT.UTF-8) [!] Android toolchain - develop for Android devices (Android SDK version 29.0.2) ✗ Android licenses not accepted. To resolve this, run: flutter doctor --android-licenses [!] Android Studio (version 3.5) ✗ Flutter plugin not installed; this adds Flutter specific functionality. ✗ Dart plugin not installed; this adds Dart specific functionality. [!] Connected device ! No devices available ! Doctor found issues in 3 categories.

Of course the issue with the Android toolchain has to be resolved in order to build for Android. Run this command to accept the licenses:

$ flutter doctor --android-licenses

Use the flutter channel command to switch channels after installation. It’s just like switching branches on Git (and that’s actually what it does). You use it in the following way:

$ flutter channel <channel_name>

…where you’d replace <channel_name> with the release channel you want to switch to.

After doing that, or whenever you feel the need to do it, you need to update your installation. You might consider running this every once in a while or when a major update comes out if you follow Flutter news. Run this command:

$ flutter upgrade

Building for Mobile

You can build for Android very easily: the flutter build command supports it by default, and it allows you to build both APKs and newfangled app bundles.

All you need to do is to create a project with flutter create, which will generate some code for an example app and the necessary android and ios folders.

When you’re done coding you can either run:

  • flutter build apk or flutter build appbundle to generate the necessary app files to distribute, or
  • flutter run to run the app on a connected device or emulator directly.

When you run the app on a phone or emulator with flutter run, you can use the R button on the keyboard to use stateful hot reload. This feature updates what’s displayed on the phone or emulator to reflect the changes you’ve made to the code without requiring a full rebuild.

If you input a capital R character to the debug console, you trigger a hot restart. This restart doesn’t preserve state and is necessary for bigger changes to the app.

If you’re using a GUI IDE, you can trigger a hot reload using the bolt icon button and a hot restart with the typical refresh button.

Building for the Desktop

To build apps for the desktop on Fedora, use the flutter-desktop-embedding repository. The flutter create command doesn’t have templates for desktop Linux apps yet. That repository contains examples of desktop apps and files required to build on desktop, as well as examples of plugins for desktop apps.

To build or run apps for Linux, you also need to be on the master release channel and enable Linux desktop app development. To do this, run:

$ flutter config --enable-linux-desktop

After that, you can use flutter run to run the app on your development workstation directly, or run flutter build linux to build a binary file in the build/ directory.

If those commands don’t work, run this command in the project directory to generate the required files to build in the linux/ directory:

$ flutter create .

Building for the Web

Starting with Flutter 1.12, you can build Web apps using Flutter with the mainline codebase, without having to use the flutter_web forked libraries, but you have to be running on the beta channel.

If you are (you can switch to it using flutter channel beta and flutter upgrade as we’ve seen earlier), you need to enable web development by running flutter config –enable-web.

After doing that, you can run flutter run -d web and a local web server will be started from which you can access your app. The command returns the URL at which the server is listening, including the port number.

You can also run flutter build web to build the static website files in the build/ directory.

If those commands don’t work, run this command in the project directory to generate the required files to build in the web/ directory:

$ flutter create .

Packages for Installing Flutter

Other distributions have packages or community repositories to install and update in a more straightforward and intuitive way. However, at the time of writing, no such thing exists for Flutter. If you have experience packaging RPMs for Fedora, consider contributing to this GitHub repository for this COPR package.

The next step is learning Flutter. You can do that in a number of ways:

  • Read the good API reference documentation on the official site
  • Watching some of the introductory video courses available online
  • Read one of the many books out there today. [Check out the author’s bio for a suggestion! — Ed.]

Photo by Randall Ruiz on Unsplash.

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Use Postfix to get email from your Fedora system

Communication is key. Your computer might be trying to tell you something important. But if your mail transport agent (MTA) isn’t properly configured, you might not be getting the notifications. Postfix is a MTA that’s easy to configure and known for a strong security record. Follow these steps to ensure that email notifications sent from local services will get routed to your internet email account through the Postfix MTA.

Install packages

Use dnf to install the required packages (you configured sudo, right?):

$ sudo -i
# dnf install postfix mailx

If you previously had a different MTA configured, you may need to set Postfix to be the system default. Use the alternatives command to set your system default MTA:

$ sudo alternatives --config mta
There are 2 programs which provide 'mta'. Selection Command
*+ 1 /usr/sbin/sendmail.sendmail 2 /usr/sbin/sendmail.postfix
Enter to keep the current selection[+], or type selection number: 2

Create a password_maps file

You will need to create a Postfix lookup table entry containing the email address and password of the account that you want to use to for sending email:

# [email protected]
# MY_EMAIL_PASSWORD=abcdefghijklmnop
# MY_SMTP_SERVER=smtp.gmail.com
# MY_SMTP_SERVER_PORT=587
# echo "[$MY_SMTP_SERVER]:$MY_SMTP_SERVER_PORT $MY_EMAIL_ADDRESS:$MY_EMAIL_PASSWORD" >> /etc/postfix/password_maps
# chmod 600 /etc/postfix/password_maps
# unset MY_EMAIL_PASSWORD
# history -c

If you are using a Gmail account, you’ll need to configure an “app password” for Postfix, rather than using your gmail password. See “Sign in using App Passwords” for instructions on configuring an app password.

Next, you must run the postmap command against the Postfix lookup table to create or update the hashed version of the file that Postfix actually uses:

# postmap /etc/postfix/password_maps

The hashed version will have the same file name but it will be suffixed with .db.

Update the main.cf file

Update Postfix’s main.cf configuration file to reference the Postfix lookup table you just created. Edit the file and add these lines.

relayhost = smtp.gmail.com:587
smtp_tls_security_level = verify
smtp_tls_mandatory_ciphers = high
smtp_tls_verify_cert_match = hostname
smtp_sasl_auth_enable = yes
smtp_sasl_security_options = noanonymous
smtp_sasl_password_maps = hash:/etc/postfix/password_maps

The example assumes you’re using Gmail for the relayhost setting, but you can substitute the correct hostname and port for the mail host to which your system should hand off mail for sending.

For the most up-to-date details about the above configuration options, see the man page:

$ man postconf.5

Enable, start, and test Postfix

After you have updated the main.cf file, enable and start the Postfix service:

# systemctl enable --now postfix.service

You can then exit your sudo session as root using the exit command or Ctrl+D. You should now be able to test your configuration with the mail command:

$ echo 'It worked!' | mail -s "Test: $(date)" [email protected]

Update services

If you have services like logwatch, mdadm, fail2ban, apcupsd or certwatch installed, you can now update their configurations so that their email notifications will go to your internet email address.

Optionally, you may want to configure all email that is sent to your local system’s root account to go to your internet email address. Add this line to the /etc/aliases file on your system (you’ll need to use sudo to edit this file, or switch to the root account first):

root: [email protected]

Now run this command to re-read the aliases:

# newaliases
  • TIP: If you are using Gmail, you can add an alpha-numeric mark between your username and the @ symbol as demonstrated above to make it easier to identify and filter the email that you will receive from your computer(s).

Troubleshooting

View the mail queue:

$ mailq

Clear all email from the queues:

# postsuper -d ALL

Filter the configuration settings for interesting values:

$ postconf | grep "^relayhost\|^smtp_"

View the postfix/smtp logs:

$ journalctl --no-pager -t postfix/smtp

Reload postfix after making configuration changes:

$ systemctl reload postfix

Photo by Sharon McCutcheon on Unsplash.