diff --git a/scripts/experimental_helper.sh b/scripts/experimental_helper.sh
index b9e72d0..fec47d8 100644
--- a/scripts/experimental_helper.sh
+++ b/scripts/experimental_helper.sh
@@ -104,3 +104,132 @@ ynh_delete_file_checksum () {
 	local checksum_setting_name=checksum_${1//[\/ ]/_}	# Replace all '/' and ' ' by '_'
 	ynh_app_setting_delete $app $checksum_setting_name
 }
+
+# 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) Program to check the integrity (sha256sum, md5sum...)
+# # default: sha256
+# SOURCE_SUM_PRG=sha256
+# # (Optional) Archive format
+# # default: tar.gz
+# SOURCE_FORMAT=tar.gz
+# # (Optional) Put false if sources 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 
+# # (Optional) If it set as false don't extract the source.
+# # (Useful to get a debian package or a python wheel.)
+# # default: true
+# SOURCE_EXTRACT=(true|false)
+#
+# Details:
+# This helper downloads sources from SOURCE_URL if there is no local source
+# archive in /opt/yunohost-apps-src/APP_ID/SOURCE_FILENAME
+#
+# Next, it checks the integrity with "SOURCE_SUM_PRG -c --status" command.
+#
+# If it's ok, the source archive will be uncompressed 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 applied 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 equals "app"
+
+    local src_file_path="$YNH_CWD/../conf/${src_id}.src"
+    # In case of restore script the src file is in an other path.
+    # So try to use the restore path if the general path point to no file.
+    if [[ ! -e "$src_file_path" ]]; then
+        src_file_path="$YNH_CWD/../settings/conf/${src_id}.src"
+    fi
+
+    # Load value from configuration file (see above for a small doc about this file
+    # format)
+    local src_url=$(grep 'SOURCE_URL=' "$src_file_path" | cut -d= -f2-)
+    local src_sum=$(grep 'SOURCE_SUM=' "$src_file_path" | cut -d= -f2-)
+    local src_sumprg=$(grep 'SOURCE_SUM_PRG=' "$src_file_path" | cut -d= -f2-)
+    local src_format=$(grep 'SOURCE_FORMAT=' "$src_file_path" | cut -d= -f2-)
+    local src_extract=$(grep 'SOURCE_EXTRACT=' "$src_file_path" | cut -d= -f2-)
+    local src_in_subdir=$(grep 'SOURCE_IN_SUBDIR=' "$src_file_path" | cut -d= -f2-)
+    local src_filename=$(grep 'SOURCE_FILENAME=' "$src_file_path" | cut -d= -f2-)
+
+    # Default value
+    src_sumprg=${src_sumprg:-sha256sum}
+    src_in_subdir=${src_in_subdir:-true}
+    src_format=${src_format:-tar.gz}
+    src_format=$(echo "$src_format" | tr '[:upper:]' '[:lower:]')
+    src_extract=${src_extract:-true}
+    if [ "$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
+        cp $local_src $src_filename
+    else    # If not, download the source
+        local out=`wget -nv -O $src_filename $src_url 2>&1` || ynh_print_err $out
+    fi
+
+    # Check the control sum
+    echo "${src_sum} ${src_filename}" | ${src_sumprg} -c --status \
+        || ynh_die "Corrupt source"
+
+    # Extract source into the app dir
+    mkdir -p "$dest_dir"
+    
+    if ! "$src_extract"
+    then
+        mv $src_filename $dest_dir
+    elif [ "$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"
+            cp -a $tmp_dir/*/. "$dest_dir"
+            ynh_secure_remove "$tmp_dir"
+        else
+            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
+            tar -xf $src_filename -C "$dest_dir" $strip
+        else
+            ynh_die "Archive format unrecognized."
+        fi
+    fi
+
+    # Apply patches
+    if (( $(find $YNH_CWD/../sources/patches/ -type f -name "${src_id}-*.patch" 2> /dev/null | wc -l) > "0" )); then
+        local old_dir=$(pwd)
+        (cd "$dest_dir" \
+            && for p in $YNH_CWD/../sources/patches/${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_CWD/../sources/extra_files/${src_id}"; then
+        cp -a $YNH_CWD/../sources/extra_files/$src_id/. "$dest_dir"
+    fi
+}