Join Codeheat Coding Contest 2017

Codeheat is a coding contest for developers interested in contributing to Open Source software and hardware projects at FOSSASIA.  Join development of real world software applications, build up your developer profile, learn new new coding skills, collaborate with the community and make new friends from around the world! Sign up for #CodeHeat here now and follow Codeheat on Twitter.

The contest runs until 1st February 2018. All FOSSASIA projects take part in Codeheat including:

Grand prize winners will be invited to present their work at the FOSSASIA OpenTechSummit in Singapore from March 23rd -25th 2018 and will get 600 SGD in travel funding to attend, plus a free speaker ticket and beautiful Swag.

Our jury will choose three winners from the top 10 contributors according to code quality and relevance of commits for the project. The jury also takes other contributions like submitted weekly scrum reports and monthly technical blog posts into account, but of course awesome code is the most important item on the list.

Other participants will have the chance to win Tshirts, Swag and vouchers to attend Open Tech events in the region and will get certificates of participation.

codeheat-logo

Team mentors and jury members from 10 different countries support participants of the contest.

Participants should take the time to read through the contest FAQ and familiarize themselves with the introductory information and Readme.md of each project before starting to work on an issue.

Developers interested in the contest can also contact mentors through project channels on the FOSSASIA gitter.

Additional Links

Website: codeheat.org

Codeheat Twitter: twitter.com/codeheat_

Codeheat Facebook: facebook.com/codeheat.org

Participating Projects: All FOSSASIA Repositories on GitHub at github.com/fossasia

Implementing “Change Password” API in Open Event Frontend

In Open Event Frontend, users can change the password for their account in the ‘Settings’ section. Changing one’s password will require the previous password of the same account which ensures the security. To implement change in password API, we created a REST endpoint here since the password cannot be included in the user model and thereby exposed to the client.

There is also a check on the server side of the old password. Thus, if the old password entered matches the one on the server, the post is successful and the server saves the new password. We achieve this as follows:

We have a change password form located at ‘settings/change-password’, which contains three input fields for old password, new password and confirm new password.

On submitting the form, we pass the action from the component to the controller.

Components consist of two parts: a template written in Handlebars, and a source file written in JavaScript that defines the component’s behavior.

Controllers behave like a specialized type of Component that is rendered by the router when entering a Route.

We could have handled this action in component itself. But, Ember JS’ main principle is DDAU i.e data down actions up. That is the main reason why we handle the action in out controller.

submit() {
      this.onValid(() => {
      this.sendAction('changePassword', this.getProperties('passwordCurrent', 'passwordNew'));
      });
}

Thus, we handle the action in our controller as follows:

 changePassword(passwordData) {
      this.set('isLoading', true);
      let payload = {
        'data': {
          'old-password' : passwordData.passwordCurrent,
          'new-password' : passwordData.passwordNew
        }
      };
      this.get('loader')
        .post('/auth/change-password', payload)
        .then(() => {
          this.get('notify').success(this.l10n.t('Password updated successfully'));
        })
        .catch(error => {
          if (error.error) {
            this.get('notify').error(this.l10n.t(error.error));
          } else {
            this.get('notify').error(this.l10n.t('Unexpected error. Password did not change.'));
          }
        })
        .finally(() => {
          this.set('isLoading', false);
          this.setProperties({ 'passwordCurrent': '', 'passwordNew': '', 'passwordRepeat': '' });
        });
    }

Here, we are getting the old password and the new password passed from the form and making a POST to the endpoint:

v1/auth/change-password

If the old password check goes successful on the server side, the server returns a successful response:

{ 
 "email": "[email protected]",
 "id": "1",
 "name": "example",
 "password-changed": true
}

Thus, the user can change password in Open Event Frontend.
Resources: Docs on loader service in Ember JS

badgeYAY – An abrupt flow of code

Badgeyay is a web application which takes a CSV file, an image file and an optional config.json file, and converts them into a PDF file which consist of a set of badges as per the data in the CSV and the image as its background. In order to contribute to the badgeyay repository, a contributor is expected to have some knowledge of Python Flask, HTML and CSS. An understanding of git version control system is inevitable in open source.

Flask – Web development in baby steps

First things first – Having a local copy

Sign up for GitHub and head over to the Badgeyay repository. Then follow these steps.

  1. Go ahead and Fork the repository
  2. Star the repository
  3. Get the clone of the forked version on you local machine using git clone https://github.com/<username>/badgeyay.git
  4. Add upstream using git remote add upstream https://github.com/fossasia/badgeyay.git

How a flask application works

A flask application basically consists of an app.py or main.py file which is run using the command python main.py

The main.py file consists of:


from flask import Flask, render_template
app = Flask(__name__)
@app.route('/')
def index():
return render_template('index.html')
if __name__ == '__main__':
app.run(debug=True)

This snippet starts the flask server at localhost:5000 and index.html template gets rendered on visiting the root url. All the templates reside in templates folder while the static asset files are stored in static folder.

Steps:

  1. First. we imported the Flask class and a function render_template.
  2. Next, we created a new instance of the Flask class.
  3. We then mapped the URL / to the function index(). Now, when someone visits this URL, the function index() will execute.
  4. The function index() uses the Flask function render_template() to render the index.html template we just created from the templates/ folder to the browser.
  5. Finally, we use run() to run our app on a local server. We’ll set the debug flag to true, so we can view any applicable error messages if something goes wrong, and so that the local server automatically reloads after we’ve made changes to the code.

The template consists of a base layout which is extended by the pages.

templates/layout.html

<!DOCTYPE html>
<html>
<head>
<title>Flask App</title>
</head>
<body>
<header>
<h1 class="logo">Flask App</h1>
</header>

{% block content %}
{% endblock %}

</body>
</html>

templates/index.html

{% extends "layout.html" %}
{% block content %}
<h2>Welcome to the Flask app</h2>
<h3>This is the index page for the Flask app</h3>
<h3>{% endblock %}</h3>

With this and a little understanding of python, and you are all set to contribute to flask repositories such as badgeyay.

Resources

Enhancing Settings Menu in SUSI Webchat using Material-UI Menu React Component

Material-UI is a great library for react developers since you can directly use the material components in your app. The SUSI.AI Webchat uses Material-UI (https://github.com/callemall/material-ui). In this blog we’ll see how a Menu component is implemented in settings page of susi’s web chat app.

Menu & MenuItem Component

Menu component allows you execute an action on selecting from a list. In the settings menu we want to change the state variable to which setting details is binded (ie. on change of state variable the setting details corresponding to selected menu changes).

A simple menu component is defined like this –

<Menu>
        <MenuItem primaryText="Item 1" />
        <MenuItem primaryText="Item 2" />
        <MenuItem primaryText="Item 3" />
        <MenuItem primaryText="Item 4" />
</Menu>

Menu component and MenuItem accepts some properties too. Like if you add disable={true} then the MenuItem it will disable onClick action of MenuItem.

Adding Icon

MenuItem can contain icons through defining leftIcon and rightIcon properties.

Example snippet:

<MenuItem primaryText="Download" leftIcon={<Download />} />

Output:

You can also add style to the leftIcon or rightIcon in style property of MenuItem.

Active State of MenuItem

You must be interested in assigning a different style to the active MenuItem in the Menu. This can be achieved through selectedMenuItemStyle property. It allows overriding the inline-style property of selected MenuItem.

To implement this we need to use the concept of ‘controlled component’. Each MenuItem has to be assigned a value. Also, assign the Menu with a state variable.

<Menu 
 selectedMenuItemStyle={{color: '#FFFFFF'} }   
 value={this.state.selectedItem} > 
    <MenuItem primaryText="Item 1" value='1'/> 
    <MenuItem primaryText="Item 2" value='2' /> 
</Menu>

This way the state variable will control Menu’s value and the selectedMenuItemStyle property will override the inline-style of the corresponding MenuItem.

Implement onClick function for MenuItem and change the state value.

This way you can add style to active MenuItem.

You can see the demo of how it was implemented in chat settings at https://chat.susi.ai/settings

Also, you can check out the github repo https://github.com/fossasia/chat.susi.ai

Note – Make sure that you define the state change function outside render else it will get a warning like this.

Warning: setState(…): Cannot update during an existing state transition (such as within `render` or another component’s constructor). Render methods should be a pure function of props and state; constructor side-effects are an anti-pattern, but can be moved to `componentWillMount`.

This will result in abnormal behaviour in runtime. So keep that mind in while creating the function to change the state.

Resources

 

Getting Started Developing on Phimpme Android

Phimpme is an Android app for editing photos and sharing them on social media. To participate in project start by learning how people contribute in open source, learning about the version control system Git and other tools like Codacy and Travis.

Firstly, sign up for GitHub. Secondly, find the open source projects that interest you. Now as for me I started with Phimpme. Then follow these steps:

  1. Go through the project ReadMe.md and read all the technologies and tools they are using.
  2. Now fork that repo in your account.
  3. Open the Android Studio/Other applications that are required for that project and import the project through Git.
  4. For Android Studio sync all the Gradle files and other changes and you are all done and ready for the development process.

Install the app and run it on a phone. Now explore each and every bit use this app as a tester, think about the end cases and boundary condition that will make the app ‘ANR’ (App not responding) dialog appear. Congratulations you are ready to create an issue if that is a verified and original and actually is a bug.

Next,

  • Navigate to the main repo link, you will see an issues section as follows:
  • Create a new issue and report every detail about the issue (logcat, screenshots) For eg. Refer to Issue-1120
  • Now the next step is to work on that issue
  • On your machine, you don’t have to change the code in the development branch as it’s considered to be as a bad practice. Hence checkout as a new branch.
    For eg., I checked out for the above issue as ‘crashfixed’
git checkout -b "Any branch name you want to keep"
  • Make the necessary changes to that branch and test that the code is compiling and the issue is fixed followed by
git add.
git commit -m "Fix #Issue No -Description "
git push origin branch-name
  • Now navigate to the repo and you will an option to create a Pull Request.
    Mention the Issue number and description and changes you done, include screenshots of the fixed app.For eg. Pull Request 1131.

Hence you have done your first contribution in open source while learning with git. The pull request will initiate some checks like Codacy and Travis build and then if everything works it is reviewed and merged by co-developers.

The usual way how this works is, that it should be reviewed by other co-developers. These co-developers do not need merge or write access to the repository. Any developer can review pull requests. This will also help contributors to learn about the project and make the job of core developers easier.

Resources

Creating an Installer for PSLab Desktop App

PSLab device is made useful with applications running on two platforms. One is Android and the other one is a desktop application developed using Python frameworks. Desktop application uses half a dozen of dependent libraries and they are required to be installed prior to installing the application itself.

For someone with zero or less knowledge on how to install packages in a Linux environment, this task will be quite difficult. To ease up the process of installing the desktop application in a computer, we can use a script to run specific commands which will install the dependencies and the application.

Dependencies required by PSLab  Desktop app

  • PyQt 4.7
  • Python 2.6, 2.7 or 3.x
  • NumPy, Scipy
  • pyqt4-dev-tools
  • Pyqtgraph
  • pyopengl and qt-opengl
  • iPython-qtconsole

These dependencies can be made installed using a bash script running with root permission. A bash script will have the file extension “.sh” and a header line;

#!/bin/bash

A bash script needs to be made executable by the user himself. To do this, user needs to type a one line command in the terminal as follows and enter his password;

sudo chmod +x <Name_of_the_script>.sh

The keyword “sudo” interprets as “Super User DO” and the line follows will be executed with root permission. In other words with administrative privileges to modify system settings such as copying content to system folders.

The keyword “chmod” stands for “Change Mode” which will alter the mode of a file. In current context, the file is made executable by adding the executable property to the bash script using “+x” syntax.

Once the script is made executable, it can be executed using;

sudo ./<Name_of_the_script>.sh

An installer can be made attractive by using different colors rather than the plain old text outputs. For this purpose we can use color syntax in bash script. They are represented using ANSI escape codes and following is a list of commonly used colors;

Black        0;30     Dark Gray     1;30
Red          0;31     Light Red     1;31
Green        0;32     Light Green   1;32
Brown/Orange 0;33     Yellow        1;33
Blue         0;34     Light Blue    1;34
Purple       0;35     Light Purple  1;35
Cyan         0;36     Light Cyan    1;36
Light Gray   0;37     White         1;37

As in any programming language, rather than using the same line in many places, we can define variables in a bash script. The syntax will be the variable name followed by an equal sign with the value. There cannot be spaces around the equal sign or it will generate an error.

GREEN='\033[0;32m'

These variables can be accessed using a special syntax as follows;

${GREEN}

Finally we can output a message to the console using the “echo” command

echo -e "${GREEN}Welcome to PSLab Desktop app installer${NOCOLOR}"

Note that the keyword “-e” is used to enable interpretation of the following backslash escapes.

In order to install the packages and libraries, we use two package management tools. One is “apt” which stands for “Advanced Packaging Tool” and the second is “pip” which is used to download python related packages from “Python Package Index”. The following two lines illustrates how the two commands can be accessed.

apt-get install python-pip python-dev build-essential -y

pip install pyqtgraph

The keyword “-y” avoids the confirmation prompt in console to allow installation by pressing “Y” key every time it installs a package from “apt”.

Resources:

Showing “Get started” button in SUSI Viber bot

When we start a chat with SUSI.AI on Viber i.e. SUSI Viberbot, there should be an option on how to get started with the bot. The response to it are some options like “Visit repository”, “How to contribute” which direct the user to check how SUSI.AI bot is made and prompts him/her to contribute to it. Along with that an option of “start chatting” can be shown to add up some sample queries for the user to try.

To accomplish the task at hand, we will accomplish these sub tasks:

  1. To show the “Get started” button.
  2. To show the reply to “Get started” query.
  3. To respond to the queries, nested in the response of “Get started”

Showing “Get started”:

The Viber developers platform notifies us when a user starts a conversation with our bot. To be exact, a conversation_started event is sent to our webhook and can be handled accordingly. The Viberbot shows a welcome message to the user along with a Get started button to help him/her start.

To send just the welcome message:

if (req.body.event === 'conversation_started') {
       // Welcome Message
       var options = {
           method: 'POST',
           url: 'https://chatapi.viber.com/pa/send_message',
           headers: headerBody,
           body: {
               // some required body properties here
               text: 'Welcome to SUSI.AI!, ' + req.body.user.name + '.',
               // code for showing the get started button here.
        }
           json: true
       };
 
       request(options, function(error, res, body) {
           // handle error
       });
   }

The next step is to show the “Get started” button. To show that we use a keyboard tool, provided by Viber developers platform. So after the “text” key we have the “keyboard” key and a value for it:

keyboard: {
             "Type": "keyboard",
             "DefaultHeight": true,
             "Buttons": [{
                 "ActionType": "reply",
                 "ActionBody": "Get started",
             }]
         }

The action type as shown in the code, can be “reply” or “open-url”. The “reply” action type, triggers an automatic query sent back with “Get started” (i.e. the value of “ActionBody” key), when that button gets clicked.

Hence, this code helps us tackle our first sub task:

Reply to “Get started”:

We target to make each SUSI.AI bot generic. The SUSI FBbot and SUSI Tweetbot shows some options like “Visit repository”, “Start chatting” and “How to contribute?” for the “Get started” query. We render the same answer structure in Viberbot.

The “rich_media” type helps us send buttons in our reply message. As we ought to use three buttons in our message, the button rows are three in the body object:

if(message === "Get started"){
                   var options = {
                       method: 'POST',
                       url: 'https://chatapi.viber.com/pa/send_message',
                       headers: headerBody,
                       body: {
                           // some body object properties here
                           type: 'rich_media',
                           rich_media: {
                               Type: "rich_media",
                               ButtonsGroupColumns: 6,
                               ButtonsGroupRows: 3,
                               BgColor: "#FFFFFF",
                               Buttons: buttons
                           }
                       },
                       json: true
                   };
 
                   request(options, function(error, res, body) {
                       if (error) throw new Error(error);
                       console.log(body);
                   });

As said before, 2 type of Action types are available – “open-url” and “reply”. “Visit repository” button has an “open-url” action type and “How to contribute?” or “start chatting” has a “reply” action type.

Example of “Visit repository” button:

var buttons = [{
                Columns: 6,
                Rows: 1,
                Text: "Visit repository",
                "ActionType": "open-url",
                "ActionBody": "https://www.github.com/fossasia/susi_server",
                // some text styling properties here
             }];

To respond to the “reply” action type queries:

When the “reply” action type button gets clicked, it triggers an automatic query sent back to the bot with the value same as that of the “ActionBody” key. So we just need to apply a check if the message string recieved is “Start chatting” or “How to contribute?”

For the response to “Start chatting”, we plan to show sample queries for the user to try. This can be shown by using buttons with the action type as “reply”.

Code snippet to show a button with the text as “What is FOSSASIA?”:

var buttons = [{
                        Columns: 6,
                        Rows: 1,
                        Text: "What is FOSSASIA? ",
                        "ActionType": "reply",
                        "ActionBody": "What is FOSSASIA?",
                        // text styling here
                    }];

For the response to “How to contribute”, we show some messages to help the user contribute to SUSI.AI. These messages also just need buttons with it, to be able to apply the necessary action.

We respond with 2 messages to the user, both the messages have a button.

For example, a button to visit the SUSI.AI Gitter channel:

var buttons = [{
                    Columns: 6,
                    Rows: 1,
                       Text: "<font color=#323232><b>Chat on Gitter</b></font>",
                      ActionType: "open-url",
                      ActionBody: "https://www.gitter.im/fossasia/susi_server",
                      // text styling here
            }];

This way we have successfully added the “Get started” option to our Viberbot and handled all the subsequent steps.

Resources:

  1. Viber video managing chat extensions by Ingrid Lunden from Tech crunch.
  2. Develop a chat bot with node js by Slobodan Stojanović from smashing magazine.

Autolinker Component in Loklak Search

In Loklak Search the post items contain links, which are either internal or external. These links include the hashtags, mentions, and URLs. From the backend server we just received the message in the plain text format, and thus there is need to parse the plain text and render it as clickable links. These clickable links can be either internal or external. Thus we need an auto-linker component, which takes the text and render it as links.

The API of the Component

The component takes as the input the plain text, then four arrays of strings. Each containing the text to be linked. These are hashtags, mentions, links and the unshorten attribute which is used to unshorten the shortened URLs in the post. These attributes are used by the component to render the text in the appropriate format.

export class FeedLinkerComponent implements OnInit {
@Input() text: string;
@Input() hashtags: string[] = new Array<string>();
@Input() mentions: string[] = new Array<string>();
@Input() links: string[] = new Array<string>();
@Input() unshorten: Object = {};
}

The Logic of the Component

The basic logic of the component works as the following, we divide the text into chunks known as shards, we have three basic data structures for the component to work

  • The ShardType which is the type of the chunk it specifies whether it is plain, hashtags, mentions, and links.
  • The Shard which is the simple object containing the text to show, its type and the link it refers to

The StringIndexdChunks, they are utilized to index the chunks in the order in which they appear in the text.

const enum ShardType {
plain, // 0
link, // 1
hashtag, // 2
mention // 3
}

class Shard {
constructor (
public type: ShardType = ShardType.plain,
public text: String = '',
public linkTo: any = null,
public queryParams: any = null
) { }
}

interface StringIndexedChunks {
index: number;
str: string;
type: ShardType;
}

First we have a private method of the component which searches for all the elements (strings) in the text. Here we have an array which maintains the index of those chunks in the text.

private generateShards() {
const indexedChunks: StringIndexedChunks[] = [];

this.hashtags.forEach(hashtag => {
const indices = getIndicesOf(this.text, `#${hashtag}`, false);
indices.forEach(idx => {
indexedChunks.push({index: idx, str: `#${hashtag}`, type: ShardType.hashtag});
});
});

this.mentions.forEach(mention => {
const indices = getIndicesOf(this.text, `@${mention}`, false);
indices.forEach(idx => {
indexedChunks.push({index: idx, str: `@${mention}`, type: ShardType.mention});
});
});
}

Then we sort the chunks according to their indexes in the text. This gives us sorted array which consists of all the chunks sorted according to the indexes as they appear in the text.

indexedChunks.sort((a, b) => { return (a.index > b.index) ? 1 : (a.index < b.index) ? -1 : 0; });

The next part of the logic is to generate the shard array, an array which contains each chunk, once. To do this we iterate over the Sorted Indexed array created in the previous step and use it split the text into chunks. We iterate over the text and take substrings using the indexes of each element.

let startIndex = 0;
const endIndex = this.text.length;

indexedChunks.forEach(element => {
if (startIndex !== element.index) {
const shard = new Shard(ShardType.plain, this.text.substring(startIndex, element.index));
this.shardArray.push(shard);
startIndex = element.index;
}
if (startIndex === element.index) {
const str = this.text.substring(startIndex, element.index + element.str.length);
const shard = new Shard(element.type, str);
switch (element.type) {
case ShardType.link: {
if (this.unshorten[element.str]) {
shard.linkTo = str;
shard.text = this.unshorten[element.str];
}
else {
shard.linkTo = str;
}
break;
}

case ShardType.hashtag: {
shard.linkTo = ['/search'];
shard.queryParams = { query : str };
break;
}

case ShardType.mention: {
shard.linkTo = ['/search'];
shard.queryParams = { query : `from:${str.substring(1)}` };
break;
}
}
this.shardArray.push(shard);
startIndex += element.str.length;
}
});

if (startIndex !== endIndex) {
const shard = new Shard(ShardType.plain, this.text.substring(startIndex));
this.shardArray.push(shard);
}

After this we have generated the chunks of the text, now the only task is to write the view of the component which uses this Shard Array to render the linked elements.

<div class="textWrapper">
<span *ngFor="let shard of shardArray">
<span *ngIf="shard.type === 0"> <!-- Plain -->
{{shard.text}}
</span>
<span *ngIf="shard.type === 1"> <!-- URL Links -->
<a>{{shard.text}}</a>
</span>
<span *ngIf="shard.type === 2"> <!-- Hashtag -->
<a [routerLink]="shard.linkTo" [queryParams]="shard.queryParams">{{shard.text}}</a>
</span>
<span *ngIf="shard.type === 3"> <!-- Mention -->
<a [routerLink]="shard.linkTo" [queryParams]="shard.queryParams">{{shard.text}}</a>
</span>
</span>
</div>
  • This renders the chunks and handles the links of both internal and external type.
  • It also also makes sure that the links get unshortened properly using the unshorten API property.
  • Uses routerLink, angular property to link in application URLs, for asynchronous reloading while clicking links.

Resources and Links

This component is inspired from the two main open source libraries.

Earlier these libraries were used in the project, but as the need of unshortening and asynchronous linking appeared in the application, a custom implementation was needed to be implemented.

Creating Settings Screen in SUSI Android Using PreferenceActivity and Kotlin

An Android application often includes settings that allow the user to modify features of the app. For example, SUSI Android app allows users to specify whether they want to use in built mic to give speech input or not. Different settings in SUSI Android app and their purpose are given below

Setting                                        Purpose
Enter As Send It allows users to specify whether they want to use enter key to send message or to add new line.
Mic Input It allows users to specify whether they want to use in built mic to give speech input or not.
Speech Always It allows users to specify whether they want voice output in case of speech input or not.
Speech Output It allows users to specify whether they want speech output irrespective of input type or not.
Language It allows users to set different query language.
Reset Password It allows users to change password.
Select Server It allows users to specify whether they want to use custom server or not.

Android provides a powerful framework, Preference framework, that allows us to define the way we want preferences. In this blog post, I will show you how Settings UI is created using Preference framework and Kotlin in SUSI Android.

Advantages of using Preference are:

  • It has own UI so we don‘t have to develop our own UI for it
  • It stores the string into the SharedPreferences so we don’t need to manage the values in SharedPreference.

First, we will add the dependency in build.gradle(project) file as shown below.

compile ‘com.takisoft.fix:preference-v7:25.4.0.3’

To create the custom style for our Settings Activity screen we can set

android:theme=“@style/PreferencesThemeLight”

as the base theme and can apply various other modifications and colour over this. By default, it has the usual Day and Night theme with NoActionBar extension.

Layout Design

I used PreferenceScreen as the main container to create UI of Settings and filled it with the other components. Different components used are following:

  • SwitchPreferenceCompat: This gives us the Switch Preference which we can use to toggle between two different modes in the setting.
<com.takisoft.fix.support.v7.preference.SwitchPreferenceCompat

android:defaultValue=”true”

  • PreferenceCategory: It is used for grouping the preference. For example, Chat Settings, Mic Settings, Speech Settings etc are different groups in settings.

  • ListPreference: This preference display list of values and help in selecting one. For example in setLanguage option ListPreference is used to show a list of query language. List of query language is provided via xml file array.xml (res/values). Attribute android:entries point to arrays languagentries and android:entryValue holds the corresponding value defined for each of the languages.
<ListPreference

android:title=“@string/Language”
android:key=“Lang_Select”

android:entries=“@array/languagentries”

android:entryValues=“@array/languagentry”

</ListPreference>

Implementation in SUSI Android

All the logic related to Preferences and their action is written in ChatSettingsFragment class. ChatSettingsFragment extends PreferenceFragmentCompat class.

class ChatSettingsFragment : PreferenceFragmentCompat()

Fragment populate the preferences when created. addPreferencesFromResource method is used to inflate view from xml.

addPreferencesFromResource(R.xml.pref_settings)

Reference

Creating Modified Initrd for Meilix

We are modifying the Initrd file in order to modify the live user configuration which is not available via skel but can be modified by editing the casper configuration like hostname or the systemd configuration.

Linux has the Initrd or “Initial ram-disk” used during the boot process. A Linux kernel is modular. The Kernel files, drivers, reside in separate files, i.e., kernel modules. The kernel does not require drivers as BIOS handles all the work of loading Initrd into the memory. After the kernel is loaded, it starts the boot process. Initrd contains all the drivers Linux needs to boot and the user can rebuild Initrd without changing the kernel.

Files inside Initrd

The files inside Initrd include the conf where the casper configuration is found which is required for the live user creation and its configuration.

The Initrd file is used when booting a live Meilix and can be found in the casper directory of the ISO.

We start with downloading the ISO and mounting it:

sudo mount -o loop meilix-i386.iso /mnt

Modifying the Initrd

Now extract the content into a folder so that one can modify them. It depends on the image type in the Meilix. We have the image in lz format it can be in gzip format for other distributions.

mkdir initrd-tmp
  cd initrd-tmp
lzma -dc -S .lz /mnt/casper/initrd.lz | cpio -id

 

Now we can modify the files like hostname or the files required to run during boot. The Initrd file is responsible for all the configuration available to the live user like the theme for Plymouth. We can modify the boot menu or plymouth or the files and folders the user gets like the default wallpaper.

Repack the modified files into a new initrd:

find . | cpio --quiet --dereference -o -H newc | gzip -9 > ~/new-initrd.gz

 

These are steps to modify the Initrd file which can be used to customize the Meilix live user configuration like hostname, Plymouth theme and user files.

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