[enh] Add app helpers to parse plain command output

data/apps/helpers.d/user

@@ -1,5 +1,15 @@
-
 # Check if a user exists
+#
+# usage: ynh_user_exists username
+# | ret: retcode - 0 if user exists, 1 otherwise
 ynh_user_exists() {
     sudo yunohost user list --json | grep -q "\"username\": \"${1}\""
-}
+}
+
+# Retrieve a user information
+#
+# usage: ynh_user_info username key
+# | ret: string - the key's value
+ynh_user_get_info() {
+    sudo yunohost user info "${1}" --plain | ynh_get_plain_key "${2}"
+}

data/apps/helpers.d/utils

@@ -0,0 +1,24 @@
+# Extract a key from a plain command output
+#
+# usage: ynh_get_plain_key key [subkey [subsubkey ...]]
+# | ret: string - the key's value
+ynh_get_plain_key() {
+    prefix="#"
+    founded=0
+    key=$1
+    shift
+    while read line; do
+        if [[ "$founded" == "1" ]] ; then
+            [[ "$line" =~ ^${prefix}[^#] ]] && return
+            echo $line
+        elif [[ "$line" =~ ^${prefix}${key}$ ]]; then
+            if [[ -n "$1" ]]; then
+                prefix+="#"
+                key=$1
+                shift
+            else
+                founded=1
+            fi
+        fi
+    done
+}