diff --git a/scripts/_common.sh b/scripts/_common.sh
new file mode 100644
index 0000000..b179bb1
--- /dev/null
+++ b/scripts/_common.sh
@@ -0,0 +1,848 @@
+#!/bin/bash
+
+#=================================================
+#=================================================
+# TESTING
+#=================================================
+#=================================================
+
+YNH_EXECUTION_DIR="."
+
+ynh_backup_abstract () {
+	# A intégrer à ynh_backup directement.
+	ynh_backup "$@"
+	echo "$2" "$1" >> backup_list
+}
+
+ynh_restore_file () {
+	file_and_dest=$(grep "^$1" backup_list)
+	backup_file=${file_and_dest%% *}
+	backup_dest=${file_and_dest#* }
+	if [ -f "$backup_dest" ]; then
+		ynh_die "There is already a file at this path: $backup_dest"
+	fi
+	if test -d "$backup_file"; then
+		sudo cp -a "$backup_file/." "$backup_dest"
+	else
+		sudo cp -a "$backup_file" "$backup_dest"
+	fi
+}
+
+ynh_fpm_config () {
+	finalphpconf="/etc/php5/fpm/pool.d/$app.conf"
+	ynh_backup_if_checksum_is_different "$finalphpconf" 1
+	sudo cp ../conf/php-fpm.conf "$finalphpconf"
+	ynh_replace_string "__NAMETOCHANGE__" "$app" "$finalphpconf"
+	ynh_replace_string "__FINALPATH__" "$final_path" "$finalphpconf"
+	ynh_replace_string "__USER__" "$app" "$finalphpconf"
+	sudo chown root: "$finalphpconf"
+	ynh_store_file_checksum "$finalphpconf"
+
+	if [ -e "../conf/php-fpm.ini" ]
+	then
+		finalphpini="/etc/php5/fpm/conf.d/20-$app.ini"
+		ynh_backup_if_checksum_is_different "$finalphpini" 1
+		sudo cp ../conf/php-fpm.ini "$finalphpini"
+		sudo chown root: "$finalphpini"
+		ynh_store_file_checksum "$finalphpini"
+	fi
+
+	sudo systemctl reload php5-fpm
+}
+
+ynh_remove_fpm_config () {
+	ynh_secure_remove "/etc/php5/fpm/pool.d/$app.conf"
+	ynh_secure_remove "/etc/php5/fpm/conf.d/20-$app.ini"
+	sudo systemctl reload php5-fpm
+}
+
+ynh_nginx_config () {
+	finalnginxconf="/etc/nginx/conf.d/$domain.d/$app.conf"
+	ynh_backup_if_checksum_is_different "$finalnginxconf" 1
+	sudo cp ../conf/nginx.conf "$finalnginxconf"
+
+	# To avoid a break by set -u, use a void substitution ${var:-}. If the variable is not set, it's simply set with an empty variable.
+	# Substitute in a nginx config file only if the variable is not empty
+	if test -n "${path_url:-}"; then
+		ynh_replace_string "__PATH__" "$path_url" "$finalnginxconf"
+	fi
+	if test -n "${domain:-}"; then
+		ynh_replace_string "__DOMAIN__" "$domain" "$finalnginxconf"
+	fi
+	if test -n "${port:-}"; then
+		ynh_replace_string "__PORT__" "$port" "$finalnginxconf"
+	fi
+	if test -n "${app:-}"; then
+		ynh_replace_string "__NAME__" "$app" "$finalnginxconf"
+	fi
+	if test -n "${final_path:-}"; then
+		ynh_replace_string "__FINALPATH__" "$final_path" "$finalnginxconf"
+	fi
+	ynh_store_file_checksum "$finalnginxconf"
+
+	sudo systemctl reload nginx
+}
+
+ynh_remove_nginx_config () {
+	ynh_secure_remove "/etc/nginx/conf.d/$domain.d/$app.conf"
+	sudo systemctl reload nginx
+}
+
+ynh_systemd_config () {
+	finalsystemdconf="/etc/systemd/system/$app.service"
+	ynh_backup_if_checksum_is_different "$finalsystemdconf" 1
+	sudo cp ../conf/systemd.service "$finalsystemdconf"
+
+	# To avoid a break by set -u, use a void substitution ${var:-}. If the variable is not set, it's simply set with an empty variable.
+	# Substitute in a nginx config file only if the variable is not empty
+	if test -n "${final_path:-}"; then
+		ynh_replace_string "__FINALPATH__" "$final_path" "$finalsystemdconf"
+	fi
+	if test -n "${app:-}"; then
+		ynh_replace_string "__APP__" "$app" "$finalsystemdconf"
+	fi
+	ynh_store_file_checksum "$finalsystemdconf"
+
+	sudo chown root: "$finalsystemdconf"
+	sudo systemctl enable $app
+	sudo systemctl daemon-reload
+}
+
+ynh_remove_systemd_config () {
+	finalsystemdconf="/etc/systemd/system/$app.service"
+	if [ -e "$finalsystemdconf" ]; then
+		sudo systemctl stop $app
+		sudo systemctl disable $app
+		ynh_secure_remove "$finalsystemdconf"
+	fi
+}
+
+#=================================================
+#=================================================
+
+#=================================================
+# CHECKING
+#=================================================
+
+CHECK_DOMAINPATH () {	# Vérifie la disponibilité du path et du domaine.
+	sudo yunohost app checkurl $domain$path_url -a $app
+}
+
+CHECK_FINALPATH () {	# Vérifie que le dossier de destination n'est pas déjà utilisé.
+	final_path=/var/www/$app
+	test ! -e "$final_path" || ynh_die "This path already contains a folder"
+}
+
+#=================================================
+# DISPLAYING
+#=================================================
+
+NO_PRINT () {	# Supprime l'affichage dans stdout pour la commande en argument.
+	set +x
+	$@
+	set -x
+}
+
+WARNING () {	# Écrit sur le canal d'erreur pour passer en warning.
+	$@ >&2
+}
+
+SUPPRESS_WARNING () {	# Force l'écriture sur la sortie standard
+	$@ 2>&1
+}
+
+QUIET () {	# Redirige la sortie standard dans /dev/null
+	$@ > /dev/null
+}
+
+ALL_QUIET () {	# Redirige la sortie standard et d'erreur dans /dev/null
+	$@ > /dev/null 2>&1
+}
+
+#=================================================
+# BACKUP
+#=================================================
+
+BACKUP_FAIL_UPGRADE () {
+	WARNING echo "Upgrade failed."
+	app_bck=${app//_/-}	# Replace all '_' by '-'
+	if sudo yunohost backup list | grep -q $app_bck-pre-upgrade$backup_number; then	# Vérifie l'existence de l'archive avant de supprimer l'application et de restaurer
+		sudo yunohost app remove $app	# Supprime l'application avant de la restaurer.
+		sudo yunohost backup restore --ignore-hooks $app_bck-pre-upgrade$backup_number --apps $app --force	# Restore the backup if upgrade failed
+		ynh_die "The app was restored to the way it was before the failed upgrade."
+	fi
+}
+
+BACKUP_BEFORE_UPGRADE () {	# Backup the current version of the app, restore it if the upgrade fails
+	backup_number=1
+	old_backup_number=2
+	app_bck=${app//_/-}	# Replace all '_' by '-'
+	if sudo yunohost backup list | grep -q $app_bck-pre-upgrade1; then	# Vérifie l'existence d'une archive déjà numéroté à 1.
+		backup_number=2	# Et passe le numéro de l'archive à 2
+		old_backup_number=1
+	fi
+
+	sudo yunohost backup create --ignore-hooks --apps $app --name $app_bck-pre-upgrade$backup_number	# Créer un backup différent de celui existant.
+	if [ "$?" -eq 0 ]; then	# Si le backup est un succès, supprime l'archive précédente.
+		if sudo yunohost backup list | grep -q $app_bck-pre-upgrade$old_backup_number; then	# Vérifie l'existence de l'ancienne archive avant de la supprimer, pour éviter une erreur.
+			QUIET sudo yunohost backup delete $app_bck-pre-upgrade$old_backup_number
+		fi
+	else	# Si le backup a échoué
+		ynh_die "Backup failed, the upgrade process was aborted."
+	fi
+}
+
+HUMAN_SIZE () {	# Transforme une taille en Ko en une taille lisible pour un humain
+	human=$(numfmt --to=iec --from-unit=1K $1)
+	echo $human
+}
+
+CHECK_SIZE () {	# Vérifie avant chaque backup que l'espace est suffisant
+	file_to_analyse=$1
+	backup_size=$(sudo du --summarize "$file_to_analyse" | cut -f1)
+	free_space=$(sudo df --output=avail "/home/yunohost.backup" | sed 1d)
+
+	if [ $free_space -le $backup_size ]
+	then
+		WARNING echo "Espace insuffisant pour sauvegarder $file_to_analyse."
+		WARNING echo "Espace disponible: $(HUMAN_SIZE $free_space)"
+		ynh_die "Espace nécessaire: $(HUMAN_SIZE $backup_size)"
+	fi
+}
+
+#=================================================
+# PACKAGE CHECK BYPASSING...
+#=================================================
+
+IS_PACKAGE_CHECK () {	# Détermine une exécution en conteneur (Non testé)
+	return $(uname -n | grep -c 'pchecker_lxc')
+}
+
+#=================================================
+# NODEJS
+#=================================================
+
+sudo_path () {
+	sudo env "PATH=$PATH" $@
+}
+
+# INFOS
+# nvm utilise la variable PATH pour stocker le path de la version de node à utiliser.
+# C'est ainsi qu'il change de version
+# En attendant une généralisation de root, il est possible d'utiliser sudo aevc le helper temporaire sudo_path
+# Il permet d'utiliser sudo en gardant le $PATH modifié
+# ynh_install_nodejs installe la version de nodejs demandée en argument, avec nvm
+# ynh_use_nodejs active une version de nodejs dans le script courant
+# 3 variables sont mises à disposition, et 2 sont stockées dans la config de l'app
+# - nodejs_path: Le chemin absolu de cette version de node
+# Utilisé pour des appels directs à npm ou node.
+# - nodejs_version: Simplement le numéro de version de nodejs pour cette application
+# - nodejs_use_version: Un alias pour charger une version de node dans le shell courant.
+# Utilisé pour démarrer un service ou un script qui utilise node ou npm
+# Dans ce cas, c'est $PATH qui contient le chemin de la version de node. Il doit être propagé sur les autres shell si nécessaire.
+
+nvm_install_dir="/opt/nvm"
+ynh_use_nodejs () {
+	nodejs_path=$(ynh_app_setting_get $app nodejs_path)
+	nodejs_version=$(ynh_app_setting_get $app nodejs_version)
+
+	# And store the command to use a specific version of node. Equal to `nvm use version`
+	nodejs_use_version="source $nvm_install_dir/nvm.sh; nvm use \"$nodejs_version\""
+
+	# Desactive set -u for this script.
+	set +u
+	eval $nodejs_use_version
+	set -u
+}
+
+ynh_install_nodejs () {
+	local nodejs_version="$1"
+	local nvm_install_script="https://raw.githubusercontent.com/creationix/nvm/v0.33.1/install.sh"
+
+	local nvm_exec="source $nvm_install_dir/nvm.sh; nvm"
+
+	sudo mkdir -p "$nvm_install_dir"
+
+	# If nvm is not previously setup, install it
+	"$nvm_exec --version" > /dev/null 2>&1 || \
+	( cd "$nvm_install_dir"
+	echo "Installation of NVM"
+	sudo wget --no-verbose "$nvm_install_script" -O- | sudo NVM_DIR="$nvm_install_dir" bash > /dev/null)
+
+	# Install the requested version of nodejs
+	sudo su -c "$nvm_exec install \"$nodejs_version\" > /dev/null"
+
+	# Store the ID of this app and the version of node requested for it
+	echo "$YNH_APP_ID:$nodejs_version" | sudo tee --append "$nvm_install_dir/ynh_app_version"
+
+	# Get the absolute path of this version of node
+	nodejs_path="$(dirname "$(sudo su -c "$nvm_exec which \"$nodejs_version\"")")"
+
+	# Store nodejs_path and nodejs_version into the config of this app
+	ynh_app_setting_set $app nodejs_path $nodejs_path
+	ynh_app_setting_set $app nodejs_version $nodejs_version
+
+	ynh_use_nodejs
+}
+
+ynh_remove_nodejs () {
+	nodejs_version=$(ynh_app_setting_get $app nodejs_version)
+
+	# Remove the line for this app
+	sudo sed --in-place "/$YNH_APP_ID:$nodejs_version/d" "$nvm_install_dir/ynh_app_version"
+
+	# If none another app uses this version of nodejs, remove it.
+	if ! grep --quiet "$nodejs_version" "$nvm_install_dir/ynh_app_version"
+	then
+		sudo su -c "source $nvm_install_dir/nvm.sh; nvm deactivate; nvm uninstall \"$nodejs_version\" > /dev/null"
+	fi
+
+	# If none another app uses nvm, remove nvm and clean the root's bashrc file
+	if [ ! -s "$nvm_install_dir/ynh_app_version" ]
+	then
+		ynh_secure_remove "$nvm_install_dir"
+		sudo sed --in-place "/NVM_DIR/d" /root/.bashrc
+	fi
+}
+
+#=================================================
+#=================================================
+# FUTUR YNH HELPERS
+#=================================================
+# Importer ce fichier de fonction avant celui des helpers officiel
+# Ainsi, les officiels prendront le pas sur ceux-ci le cas échéant
+#=================================================
+
+# Normalize the url path syntax
+# Handle the slash at the beginning of path and its absence at ending
+# Return a normalized url path
+#
+# example: url_path=$(ynh_normalize_url_path $url_path)
+#          ynh_normalize_url_path example -> /example
+#          ynh_normalize_url_path /example -> /example
+#          ynh_normalize_url_path /example/ -> /example
+#          ynh_normalize_url_path / -> /
+#
+# usage: ynh_normalize_url_path path_to_normalize
+# | arg: url_path_to_normalize - URL path to normalize before using it
+ynh_normalize_url_path () {
+	path_url=$1
+	test -n "$path_url" || ynh_die "ynh_normalize_url_path expect a URL path as first argument and received nothing."
+	if [ "${path_url:0:1}" != "/" ]; then    # If the first character is not a /
+		path_url="/$path_url"    # Add / at begin of path variable
+	fi
+	if [ "${path_url:${#path_url}-1}" == "/" ] && [ ${#path_url} -gt 1 ]; then    # If the last character is a / and that not the only character.
+		path_url="${path_url:0:${#path_url}-1}"	# Delete the last character
+	fi
+	echo $path_url
+}
+
+# Check if a mysql user exists
+#
+# usage: ynh_mysql_user_exists user
+# | arg: user - the user for which to check existence
+function ynh_mysql_user_exists()
+{
+	local user=$1
+	if [[ -z $(ynh_mysql_execute_as_root "SELECT User from mysql.user WHERE User = '$user';") ]]
+	then
+		return 1
+	else
+		return 0
+	fi
+}
+
+# Create a database, an user and its password. Then store the password in the app's config
+#
+# After executing this helper, the password of the created database will be available in $db_pwd
+# It will also be stored as "mysqlpwd" into the app settings.
+#
+# usage: ynh_mysql_setup_db user name [pwd]
+# | arg: user - Owner of the database
+# | arg: name - Name of the database
+# | arg: pwd - Password of the database. If not given, a password will be generated
+ynh_mysql_setup_db () {
+	local db_user="$1"
+	local db_name="$2"
+	local new_db_pwd=$(ynh_string_random)	# Generate a random password
+	db_pwd=${3:-$new_db_pwd}
+	ynh_mysql_create_db "$db_name" "$db_user" "$db_pwd"	# Create the database
+	ynh_app_setting_set $app mysqlpwd $db_pwd	# Store the password in the app's config
+}
+
+# Remove a database if it exists, and the associated user
+#
+# usage: ynh_mysql_remove_db user name
+# | arg: user - Owner of the database
+# | arg: name - Name of the database
+ynh_mysql_remove_db () {
+	local db_user="$1"
+	local db_name="$2"
+	local mysql_root_password=$(sudo cat $MYSQL_ROOT_PWD_FILE)
+	if mysqlshow -u root -p$mysql_root_password | grep -q "^| $db_name"; then	# Check if the database exists
+		echo "Removing database $db_name" >&2
+		ynh_mysql_drop_db $db_name	# Remove the database	
+	else
+		echo "Database $db_name not found" >&2
+	fi
+
+	# Remove mysql user if it exists
+	if $(ynh_mysql_user_exists $db_user); then
+		ynh_mysql_drop_user $db_user
+	fi
+}
+
+# Correct the name given in argument for mariadb
+#
+# Avoid invalid name for your database
+#
+# Exemple: dbname=$(ynh_make_valid_dbid $app)
+#
+# usage: ynh_make_valid_dbid name
+# | arg: name - name to correct
+# | ret: the corrected name
+ynh_make_valid_dbid () {
+	dbid=${1//[-.]/_}	# Mariadb doesn't support - and . in the name of databases. It will be replace by _
+	echo $dbid
+}
+
+# Manage a fail of the script
+#
+# Print a warning to inform that the script was failed
+# Execute the ynh_clean_setup function if used in the app script
+#
+# usage of ynh_clean_setup function
+# This function provide a way to clean some residual of installation that not managed by remove script.
+# To use it, simply add in your script:
+# ynh_clean_setup () {
+#        instructions...
+# }
+# This function is optionnal.
+#
+# Usage: ynh_exit_properly is used only by the helper ynh_abort_if_errors.
+# You must not use it directly.
+ynh_exit_properly () {
+	exit_code=$?
+	if [ "$exit_code" -eq 0 ]; then
+			exit 0	# Exit without error if the script ended correctly
+	fi
+
+	trap '' EXIT	# Ignore new exit signals
+	set +eu	# Do not exit anymore if a command fail or if a variable is empty
+
+	echo -e "!!\n  $app's script has encountered an error. Its execution was cancelled.\n!!" >&2
+
+	if type -t ynh_clean_setup > /dev/null; then	# Check if the function exist in the app script.
+		ynh_clean_setup	# Call the function to do specific cleaning for the app.
+	fi
+
+	ynh_die	# Exit with error status
+}
+
+# Exit if an error occurs during the execution of the script.
+#
+# Stop immediatly the execution if an error occured or if a empty variable is used.
+# The execution of the script is derivate to ynh_exit_properly function before exit.
+#
+# Usage: ynh_abort_if_errors
+ynh_abort_if_errors () {
+	set -eu	# Exit if a command fail, and if a variable is used unset.
+	trap ynh_exit_properly EXIT	# Capturing exit signals on shell script
+}
+
+# Define and install dependencies with a equivs control file
+# This helper can/should only be called once per app
+#
+# usage: ynh_install_app_dependencies dep [dep [...]]
+# | arg: dep - the package name to install in dependence
+ynh_install_app_dependencies () {
+    dependencies=$@
+    manifest_path="../manifest.json"
+    if [ ! -e "$manifest_path" ]; then
+    	manifest_path="../settings/manifest.json"	# Into the restore script, the manifest is not at the same place
+    fi
+    version=$(sudo grep '\"version\": ' "$manifest_path" | cut -d '"' -f 4)	# Retrieve the version number in the manifest file.
+    dep_app=${app//_/-}	# Replace all '_' by '-'
+
+    if ynh_package_is_installed "${dep_app}-ynh-deps"; then
+		echo "A package named ${dep_app}-ynh-deps is already installed" >&2
+    else
+        cat > ./${dep_app}-ynh-deps.control << EOF	# Make a control file for equivs-build
+Section: misc
+Priority: optional
+Package: ${dep_app}-ynh-deps
+Version: ${version}
+Depends: ${dependencies// /, }
+Architecture: all
+Description: Fake package for ${app} (YunoHost app) dependencies
+ This meta-package is only responsible of installing its dependencies.
+EOF
+        ynh_package_install_from_equivs ./${dep_app}-ynh-deps.control \
+            || ynh_die "Unable to install dependencies"	# Install the fake package and its dependencies
+        ynh_app_setting_set $app apt_dependencies $dependencies
+    fi
+}
+
+# Remove fake package and its dependencies
+#
+# Dependencies will removed only if no other package need them.
+#
+# usage: ynh_remove_app_dependencies
+ynh_remove_app_dependencies () {
+    dep_app=${app//_/-}	# Replace all '_' by '-'
+    ynh_package_autoremove ${dep_app}-ynh-deps	# Remove the fake package and its dependencies if they not still used.
+}
+
+# Use logrotate to manage the logfile
+#
+# usage: ynh_use_logrotate [logfile]
+# | arg: logfile - absolute path of logfile
+#
+# If no argument provided, a standard directory will be use. /var/log/${app}
+# You can provide a path with the directory only or with the logfile.
+# /parentdir/logdir/
+# /parentdir/logdir/logfile.log
+#
+# It's possible to use this helper several times, each config will added to same logrotate config file.
+ynh_use_logrotate () {
+	if [ "$#" -gt 0 ]; then
+		if [ "$(echo ${1##*.})" == "log" ]; then	# Keep only the extension to check if it's a logfile
+			logfile=$1	# In this case, focus logrotate on the logfile
+		else
+			logfile=$1/.log	# Else, uses the directory and all logfile into it.
+		fi
+	else
+		logfile="/var/log/${app}/.log" # Without argument, use a defaut directory in /var/log
+	fi
+	cat > ./${app}-logrotate << EOF	# Build a config file for logrotate
+$logfile {
+		# Rotate if the logfile exceeds 100Mo
+	size 100M
+		# Keep 12 old log maximum
+	rotate 12
+		# Compress the logs with gzip
+	compress
+		# Compress the log at the next cycle. So keep always 2 non compressed logs
+	delaycompress
+		# Copy and truncate the log to allow to continue write on it. Instead of move the log.
+	copytruncate
+		# Do not do an error if the log is missing
+	missingok
+		# Not rotate if the log is empty
+	notifempty
+		# Keep old logs in the same dir
+	noolddir
+}
+EOF
+	sudo mkdir -p $(dirname "$logfile")	# Create the log directory, if not exist
+	cat ${app}-logrotate | sudo tee -a /etc/logrotate.d/$app > /dev/null	# Append this config to the others for this app. If a config file already exist
+}
+
+# Remove the app's logrotate config.
+#
+# usage: ynh_remove_logrotate
+ynh_remove_logrotate () {
+	if [ -e "/etc/logrotate.d/$app" ]; then
+		sudo rm "/etc/logrotate.d/$app"
+	fi
+}
+
+# Find a free port and return it
+#
+# example: port=$(ynh_find_port 8080)
+#
+# usage: ynh_find_port begin_port
+# | arg: begin_port - port to start to search
+ynh_find_port () {
+	port=$1
+	test -n "$port" || ynh_die "The argument of ynh_find_port must be a valid port."
+	while netcat -z 127.0.0.1 $port       # Check if the port is free
+	do
+		port=$((port+1))	# Else, pass to next port
+	done
+	echo $port
+}
+
+# Create a system user
+#
+# usage: ynh_system_user_create user_name [home_dir]
+# | arg: user_name - Name of the system user that will be create
+# | arg: home_dir - Path of the home dir for the user. Usually the final path of the app. If this argument is omitted, the user will be created without home
+ynh_system_user_create () {
+	if ! ynh_system_user_exists "$1"	# Check if the user exists on the system
+	then	# If the user doesn't exist
+		if [ $# -ge 2 ]; then	# If a home dir is mentioned
+			user_home_dir="-d $2"
+		else
+			user_home_dir="--no-create-home"
+		fi
+		sudo useradd $user_home_dir --system --user-group $1 --shell /usr/sbin/nologin || ynh_die "Unable to create $1 system account"
+	fi
+}
+
+# Delete a system user
+#
+# usage: ynh_system_user_delete user_name
+# | arg: user_name - Name of the system user that will be create
+ynh_system_user_delete () {
+    if ynh_system_user_exists "$1"	# Check if the user exists on the system
+    then
+		echo "Remove the user $1" >&2
+		sudo userdel $1
+	else
+		echo "The user $1 was not found" >&2
+    fi
+}
+
+# Curl abstraction to help with POST requests to local pages (such as installation forms)
+#
+# $domain and $path_url should be defined externally (and correspond to the domain.tld and the /path (of the app?))
+#
+# example: ynh_local_curl "/install.php?installButton" "foo=$var1" "bar=$var2"
+# 
+# usage: ynh_local_curl "page_uri" "key1=value1" "key2=value2" ...
+# | arg: page_uri    - Path (relative to $path_url) of the page where POST data will be sent
+# | arg: key1=value1 - (Optionnal) POST key and corresponding value
+# | arg: key2=value2 - (Optionnal) Another POST key and corresponding value
+# | arg: ...         - (Optionnal) More POST keys and values
+ynh_local_curl () {
+	# Define url of page to curl
+	full_page_url=https://localhost$path_url$1
+
+	# Concatenate all other arguments with '&' to prepare POST data
+	POST_data=""
+	for arg in "${@:2}"
+	do
+		POST_data="${POST_data}${arg}&"
+	done
+	if [ -n "$POST_data" ]
+	then
+		# Add --data arg and remove the last character, which is an unecessary '&'
+		POST_data="--data \"${POST_data::-1}\""
+	fi
+
+	# Curl the URL
+	curl --silent --show-error -kL -H "Host: $domain" --resolve $domain:443:127.0.0.1 $POST_data "$full_page_url"
+}
+
+# Substitute/replace a string by another in a file
+#
+# usage: ynh_replace_string match_string replace_string target_file
+# | arg: match_string - String to be searched and replaced in the file
+# | arg: replace_string - String that will replace matches
+# | arg: target_file - File in which the string will be replaced.
+ynh_replace_string () {
+	delimit=@
+	match_string=${1//${delimit}/"\\${delimit}"}	# Escape the delimiter if it's in the string.
+	replace_string=${2//${delimit}/"\\${delimit}"}
+	workfile=$3
+
+	sudo sed --in-place "s${delimit}${match_string}${delimit}${replace_string}${delimit}g" "$workfile"
+}
+
+# Remove a file or a directory securely
+#
+# usage: ynh_secure_remove path_to_remove
+# | arg: path_to_remove - File or directory to remove
+ynh_secure_remove () {
+	path_to_remove=$1
+	forbidden_path=" \
+	/var/www \
+	/home/yunohost.app"
+
+	if [[ "$forbidden_path" =~ "$path_to_remove" \
+		# Match all paths or subpaths in $forbidden_path
+		|| "$path_to_remove" =~ ^/[[:alnum:]]+$ \
+		# Match all first level paths from / (Like /var, /root, etc...)
+		|| "${path_to_remove:${#path_to_remove}-1}" = "/" ]]
+		# Match if the path finishes by /. Because it seems there is an empty variable
+	then
+		echo "Avoid deleting $path_to_remove." >&2
+	else
+		if [ -e "$path_to_remove" ]
+		then
+			sudo rm -R "$path_to_remove"
+		else
+			echo "$path_to_remove wasn't deleted because it doesn't exist." >&2
+		fi
+	fi
+}
+
+# Download, check integrity, uncompress and patch the source from app.src
+#
+# The file conf/app.src need to contains:
+# 
+# SOURCE_URL=Address to download the app archive
+# SOURCE_SUM=Control sum
+# # (Optional) Programm to check the integrity (sha256sum, md5sum$YNH_EXECUTION_DIR/...)
+# # default: sha256
+# SOURCE_SUM_PRG=sha256
+# # (Optional) Archive format
+# # default: tar.gz
+# SOURCE_FORMAT=tar.gz
+# # (Optional) Put false if source are directly in the archive root
+# # default: true
+# SOURCE_IN_SUBDIR=false
+# # (Optionnal) Name of the local archive (offline setup support)
+# # default: ${src_id}.${src_format}
+# SOURCE_FILENAME=example.tar.gz 
+#
+# Details:
+# This helper download sources from SOURCE_URL if there is no local source
+# archive in /opt/yunohost-apps-src/APP_ID/SOURCE_FILENAME
+# 
+# Next, it check the integrity with "SOURCE_SUM_PRG -c --status" command.
+# 
+# If it's ok, the source archive will be uncompress in $dest_dir. If the
+# SOURCE_IN_SUBDIR is true, the first level directory of the archive will be
+# removed.
+#
+# Finally, patches named sources/patches/${src_id}-*.patch and extra files in
+# sources/extra_files/$src_id will be applyed to dest_dir
+#
+#
+# usage: ynh_setup_source dest_dir [source_id]
+# | arg: dest_dir  - Directory where to setup sources
+# | arg: source_id - Name of the app, if the package contains more than one app
+ynh_setup_source () {
+	local dest_dir=$1
+	local src_id=${2:-app} # If the argument is not given, source_id equal "app"
+
+	# Load value from configuration file (see above for a small doc about this file
+	# format)
+	local src_url=$(grep 'SOURCE_URL=' "$YNH_EXECUTION_DIR/../conf/${src_id}.src" | cut -d= -f2-)
+	local src_sum=$(grep 'SOURCE_SUM=' "$YNH_EXECUTION_DIR/../conf/${src_id}.src" | cut -d= -f2-)
+	local src_sumprg=$(grep 'SOURCE_SUM_PRG=' "$YNH_EXECUTION_DIR/../conf/${src_id}.src" | cut -d= -f2-)
+	local src_format=$(grep 'SOURCE_FORMAT=' "$YNH_EXECUTION_DIR/../conf/${src_id}.src" | cut -d= -f2-)
+	local src_in_subdir=$(grep 'SOURCE_IN_SUBDIR=' "$YNH_EXECUTION_DIR/../conf/${src_id}.src" | cut -d= -f2-)
+	local src_filename=$(grep 'SOURCE_FILENAME=' "$YNH_EXECUTION_DIR/../conf/${src_id}.src" | cut -d= -f2-)
+
+	# Default value
+	src_sumprg=${src_sumprg:-sha256sum}
+	src_in_subdir=${src_in_subdir:-true}
+	src_format=${src_format:-tar.gz}
+	src_format=$(echo "$src_format" | tr '[:upper:]' '[:lower:]')
+	if [ "$src_filename" = "" ] ; then
+		src_filename="${src_id}.${src_format}"
+	fi
+	local local_src="/opt/yunohost-apps-src/${YNH_APP_ID}/${src_filename}"
+
+	if test -e "$local_src"
+	then    # Use the local source file if it is present
+		sudo cp $local_src $src_filename
+	else    # If not, download the source
+		wget -nv -O $src_filename $src_url
+	fi
+
+	# Check the control sum
+	echo "${src_sum} ${src_filename}" | ${src_sumprg} -c --status \
+		|| ynh_die "Corrupt source"
+
+	# Extract source into the app dir
+	sudo mkdir -p "$dest_dir"
+	if [ "$src_format" = "zip" ]
+	then 
+		# Zip format
+		# Using of a temp directory, because unzip doesn't manage --strip-components
+		if $src_in_subdir ; then
+			local tmp_dir=$(mktemp -d)
+			unzip -quo $src_filename -d "$tmp_dir"
+			sudo cp -a $tmp_dir/*/. "$dest_dir"
+			ynh_secure_remove "$tmp_dir"
+		else
+			sudo unzip -quo $src_filename -d "$dest_dir"
+		fi
+	else
+		local strip=""
+		if $src_in_subdir ; then
+			strip="--strip-components 1"
+		fi
+		if [[ "$src_format" =~ ^tar.gz|tar.bz2|tar.xz$ ]] ; then
+			sudo tar -xf $src_filename -C "$dest_dir" $strip
+		else
+			ynh_die "Archive format unrecognized."
+		fi
+	fi
+
+	# Apply patches
+	if (( $(find $YNH_EXECUTION_DIR/../sources/patches/ -type f -name "${src_id}-*.patch" 2> /dev/null | wc -l) > "0" )); then
+		local old_dir=$(pwd)
+		(cd "$dest_dir" \
+			&& for p in $YNH_EXECUTION_DIR/../sources/patches/${src_id}-*.patch; do \
+				patch -p1 < $p; done) \
+			|| ynh_die "Unable to apply patches"
+		cd $old_dir
+	fi
+
+	# Add supplementary files
+	if test -e "$YNH_EXECUTION_DIR/../sources/extra_files/${src_id}"; then
+		cp -a $YNH_EXECUTION_DIR/../sources/extra_files/$src_id/. "$dest_dir"
+	fi
+
+}
+
+# Check availability of a web path
+#
+# example: ynh_webpath_available some.domain.tld /coffee
+#
+# usage: ynh_webpath_available domain path
+# | arg: domain - the domain/host of the url
+# | arg: path - the web path to check the availability of
+ynh_webpath_available () {
+	local domain=$1
+	local path=$2
+	sudo yunohost domain url-available $domain $path
+}
+
+# Register/book a web path for an app
+#
+# example: ynh_webpath_register wordpress some.domain.tld /coffee
+#
+# usage: ynh_webpath_register app domain path
+# | arg: app - the app for which the domain should be registered
+# | arg: domain - the domain/host of the web path
+# | arg: path - the web path to be registered
+ynh_webpath_register () {
+	local app=$1
+	local domain=$2
+	local path=$3
+	sudo yunohost app register-url $app $domain $path
+}
+
+# Calculate and store a file checksum into the app settings
+#
+# $app should be defined when calling this helper
+#
+# usage: ynh_store_file_checksum file
+# | arg: file - The file on which the checksum will performed, then stored.
+ynh_store_file_checksum () {
+	local checksum_setting_name=checksum_${1//[\/ ]/_}	# Replace all '/' and ' ' by '_'
+	ynh_app_setting_set $app $checksum_setting_name $(sudo md5sum "$1" | cut -d' ' -f1)
+}
+
+# Verify the checksum and backup the file if it's different
+# This helper is primarily meant to allow to easily backup personalised/manually 
+# modified config files.
+#
+# $app should be defined when calling this helper
+#
+# usage: ynh_backup_if_checksum_is_different file
+# | arg: file - The file on which the checksum test will be perfomed.
+#
+# | ret: Return the name a the backup file, or nothing
+ynh_backup_if_checksum_is_different () {
+	local file=$1
+	local checksum_setting_name=checksum_${file//[\/ ]/_}	# Replace all '/' and ' ' by '_'
+	local checksum_value=$(ynh_app_setting_get $app $checksum_setting_name)
+	if [ -n "$checksum_value" ]
+	then	# Proceed only if a value was stored into the app settings
+		if ! echo "$checksum_value $file" | sudo md5sum -c --status
+		then	# If the checksum is now different
+			backup_file="/home/yunohost.conf/backup/$file.backup.$(date '+%Y%m%d.%H%M%S')"
+			sudo mkdir -p "$(dirname "$backup_file")"
+			sudo cp -a "$file" "$backup_file"	# Backup the current file
+			echo "File $file has been manually modified since the installation or last upgrade. So it has been duplicated in $backup_file" >&2
+			echo "$backup_file"	# Return the name of the backup file
+		fi
+	fi
+}