#+TITLE:
#+AUTHOR: Bob Mottram
#+EMAIL: bob@robotics.uk.to
#+KEYWORDS: freedombox, debian, beaglebone, red matrix, email, web server, home server, internet, censorship, surveillance, social network, irc, jabber
#+DESCRIPTION: Turn the Beaglebone Black into a personal communications server
#+OPTIONS: ^:nil toc:nil
#+HTML_HEAD: <link rel="stylesheet" type="text/css" href="freedombone.css" />

#+BEGIN_CENTER
[[file:images/logo.png]]
#+END_CENTER

#+begin_export html
<center><h1>Developers Guide</h1></center>
#+end_export

* Adding extra apps
Suppose you have some internet application which you want to add to the system. To do this you need to create an app script which tells the system how to install/remove and also backup/restore. On an installed system the app scripts go into the directory:

#+begin_src bash
/usr/share/freedombone/apps
#+end_src

and within the project repo they appear within the /src/ directory. Your new app script should have the name:

#+begin_src bash
freedombone-app-[myappname]
#+end_src

The /myappname/ value should not contain any spaces and will appear in the list of available apps.

An example template for an app script is shown below. Copy this and add whatever variables and configuration you need. Search and replace /myappname/ with your own.

#+begin_src bash
#!/bin/bash
# Copyright (C) Year YourName <YourEmail>
#
# This program is free software: you can redistribute it
# and/or modify it under the terms of the GNU Affero General
# Public License as published by the Free Software Foundation,
# either version 3 of the License, or (at your option) any
# later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU Affero General Public License for more details.
#
# You should have received a copy of the GNU Affero General
# Public License along with this program.  If not, see
# <http://www.gnu.org/licenses/>.

# 'full' includes your app in the full installation and you
# can also add other variants, separated by spaces. The
# available variants will be detected automatically from the
# app scripts.
VARIANTS='full'

SOME_IMPORTANT_CONFIG_VARIABLE='some important value'
ANOTHER_IMPORTANT_CONFIG_VARIABLE='foo'
MY_FUNKY_AVATAR=https://some-domain-or-other/fro.png
MYAPPNAME_ONION_PORT=[port number]
MYAPPNAME_DB_PASSWORD=

# A directory where the data exists
MYAPP_DATA_DIR=/var/lib/somedirectory

myappname_variables=(ONION_ONLY
                     MY_USERNAME
                     SOME_IMPORTANT_CONFIG_VARIABLE
                     ANOTHER_IMPORTANT_CONFIG_VARIABLE
                     MY_FUNKY_AVATAR
                     MYAPPNAME_ONION_PORT
                     MYAPPNAME_DB_PASSWORD)

function change_password_myappname {
    PASSWORD_USERNAME="$1"
    PASSWORD_NEW="$2"
    # Do something to change the password
}

function reconfigure_myappname {
    echo -n ''
    # Do something to delete existing keys/identity and
    # generate new ones
}

function upgrade_myappname {
    echo -n ''
    # Do something to upgrade this app.
    # If it's a debian package then it will be maintained by the
    # operating system and you don't need anything here
}

function backup_local_myappname {
    # If your app has a MariaDB/MySQL database
    backup_database_to_usb myappname

    # To backup a directory
    backup_directory_to_usb $MYAPP_DATA_DIR myappname

    # if you need to backup data within individual user
    # home directories
    for d in /home/*/ ; do
        USERNAME=$(echo "$d" | awk -F '/' '{print $3}')
        if [[ $(is_valid_user "$USERNAME") == "1" ]]; then
            echo $"Backing up myappname config for $USERNAME"
            if [ -d /home/$USERNAME/.config/myappname ]; then
                backup_directory_to_usb \
                    /home/$USERNAME/.config/myappname \
                    myappname_users/$USERNAME
            fi
        fi
    done
}

function restore_local_myappname {
    temp_restore_dir=/root/tempmyappname

    # If your app has a MariaDB/MySQL database
    restore_database myappname

    # Restore some data from a directory
    # Note that we don't restore directly but to a temporary
    # directory and then copy the files. This ensures that if
    # there is a restore failure you don't end up with
    # half-copied or corrupted files
    restore_directory_from_usb $MYAPP_DATA_DIR myappname
    cp -r $temp_restore_dir/$MYAPP_DATA_DIR $MYAPP_DATA_DIR
    rm -rf $temp_restore_dir

    # If you need to restore a configuration directory for each user
    if [ -d $USB_MOUNT/backup/myappname_users ]; then
        for d in $USB_MOUNT/backup/myappname_users/*/ ; do
            USERNAME=$(echo "$d" | awk -F '/' '{print $6}')
            if [[ $(is_valid_user "$USERNAME") == "1" ]]; then
                if [ ! -d /home/$USERNAME ]; then
                    ${PROJECT_NAME}-adduser $USERNAME
                fi
                echo $"Restoring Vim config for $USERNAME"
                function_check restore_directory_from_usb
                restore_directory_from_usb $temp_restore_dir \
                                           myappname_users/$USERNAME
                cp -r $temp_restore_dir/home/$USERNAME/.config \
                      /home/$USERNAME/
                if [ ! "$?" = "0" ]; then
                    rm -rf $temp_restore_dir
                    set_user_permissions
                    backup_unmount_drive
                    exit 664
                fi
                rm -rf $temp_restore_dir
            fi
        done
    fi
}

function backup_remote_myappname {
    # this should be the same as backup_local_myappname,
    # but call the backup functions backup_directory_to_friend
    # and backup_database_to_friend
}

function restore_remote_vim {
    # this should be the same as restore_local_myappname,
    # but call the restore function restore_directory_from_friend
    # and restore_database_from_friend
}

function remove_myappname {
    # if it's a debian package then:
    apt-get -y remove --purge [my-app-package-name]

    # If your app has a MariaDB/MySQL database
    drop_database myappname

    # If your app uses an onion address
    remove_onion_service myappname ${MYAPPNAME_ONION_PORT}
}

function install_myappname {
    # if it's a debian package then:
    apt-get -y install [my-app-package-name]

    # If you need to create a MariaDB/MySQL database for the app
    MYAPPNAME_DB_PASSWORD="$(create_password 20)"
    create_database myappname "$MYAPPNAME_DB_PASSWORD" $MY_USERNAME

    # If you need to create an onion address for the app
    MYAPPNAME_ONION_HOSTNAME=$(add_onion_service myappname \
                               80 ${MYAPPNAME_ONION_PORT})

    # Do any other configuration
    # Here you might use $ONION_ONLY or
    # $SOME_IMPORTANT_CONFIG_VARIABLE

    # Mark the app as having installed successfully
    # If this variable isn't set then it will be assumed that
    # the install has failed
    APP_INSTALLED=1
}

function install_interactive_myappname {
    # Interactively obtain some values using dialog, such as
    # domain names. An avatar changing example is:
    data=$(tempfile 2>/dev/null)
    trap "rm -f $data" 0 1 2 5 15
    dialog --title $"Change your avatar" \
           --backtitle $"Freedombone Control Panel" \
           --inputbox $"Enter a URL for an image. It should be " \
                      $"approximately a square image." 8 75 2>$data
    sel=$?
    case $sel in
        0)
            MY_FUNKY_AVATAR=$(<$data)
            if [ ${#MY_FUNKY_AVATAR} -gt 3 ]; then
                clear

                # do whatever is needed to change the avatar
                # in your app

                dialog --title $"Change your avatar" \
                       --msgbox $"Your avatar has been changed" 6 40
            fi
            ;;
    esac

    # Then do the main install
    install_myappname
}

# NOTE: deliberately no exit 0
#+end_src

To test your app log into your system, select *Exit to command line* then gain root powers with:

#+begin_src bash
sudo su
#+end_src

Copy your app script to */usr/share/freedombone/apps/freedombone-app-myappname*.

And run the admin control panel:

#+begin_src bash
control
#+end_src

Select *Add/Remove Apps* and if all is well then you should see your app listed as installable. Test that installing and removing it works as expected.

Submit your working app to *https://github.com/bashrc/freedombone/issues*