Adds support for configuration file

The script can now be configured using configuration files.
If a file named ".freemobile-smsapi" is located next to the script or in user's
home directory, such file will be read to load
Alternatively, a file path can be specified using `-c` option at runtime.

This commit makes the script accept option to specify configuration filepath
and also look for configuration files in specific places.

README.md

@@ -12,19 +12,19 @@ Shell Client
 ### Possible usages:
 
 ```
-send-notification.sh "All your base are belong to us"
+send-notification.sh [options] "All your base are belong to us"
 ```
 
 ```
-uptime | send-notification.sh
+uptime | send-notification.sh [options]
 ```
 
 See `send-notification.sh -h`.
 
 ### Configuration :
 
-Script can be configured 
+Script can be configured using the following variables:
-Edit `send-notification.sh` and set the following variables:
+
 * `USER_LOGIN`: The login to use the API.
 * `API_KEY`: The secret key associated to `USER_LOGIN`.
 * `MESSAGE_HEADER` (Optional): Will be prepended to all the messages.
@@ -32,6 +32,23 @@ Edit `send-notification.sh` and set the following variables:
 * `NEWLINE_CHAR` (Optional): Char to use to create a new line (it depends on
   receiving terminal).
 
+Theses can be directly changed in the `send-notification.sh` file or set in a 
+separate configuration file named `.freemobile-smsapi` next to the script or in
+the user's home directory. A given filepath can also be specify using the `-c`
+script at runtime (`send-notification.sh -c foobar`).
+
+Configuration load process is as follows:
+
+# Uses what's in `send-notification.sh` file.
+# If `-c` option is set, test given file existence and uses what's inside.
+  Will not load any other configuration file (stops load process here).
+# Checks if a `.freemobile-smsapi` file exists next to the script and uses
+  what's inside. Will not load any other configuration file (stops load process
+  here).
+# Checks if a `.freemobile-smsapi` file exists in user's home directory
+  (`${HOME}`) and uses what's inside. Will not load any other configuration file
+  (stops load process here).
+
 
 PHP Client
 ----------

send-notification.sh

@@ -12,6 +12,14 @@
 
 
 readonly PROGNAME=$(basename $0)
+readonly PROGDIR=$(readlink -m $(dirname $0))
+
+usage_error () {
+    echo "ERROR: ${1}" >&2
+    echo ""
+    usage_help
+    exit 1
+}
 
 usage_help () {
     echo "Possible usages:"
@@ -19,11 +27,15 @@ usage_help () {
     echo "* echo \"All your base are belong to us\" | ${PROGNAME} [options]"
     echo ""
     echo "Options:"
+    echo "* -c file    specify configuration file"
     echo "* -h         display this help"
 }
 
-while getopts "h" option; do
+CONFIG_FILE=""
+while getopts "c:h" option; do
     case "$option" in
+        c) CONFIG_FILE=${OPTARG} ;;
+        :) usage_error "Invalid arguments" ;;
         h) usage_help ; exit 0 ;;
     esac
 done
@@ -66,6 +78,40 @@ MESSAGE_FOOTER="
 Le serveur de la maison"
 
 
+##
+## Fichier de configuration
+##
+
+if [ -n "${CONFIG_FILE}" ]; then
+    if [ -e "${CONFIG_FILE}" ]; then
+        . "./${CONFIG_FILE}"
+    else
+        echo "ERROR: Configuration file \"${CONFIG_FILE}\" does not exists." >&2
+        exit 2
+    fi
+else
+    if [ -e "${PROGDIR}/.freemobile-smsapi" ]; then
+        . "${PROGDIR}/.freemobile-smsapi"
+    elif [ -e "${HOME}/.freemobile-smsapi" ]; then
+        . "${HOME}/.freemobile-smsapi"
+    fi
+fi
+
+##
+## Vérifications des paramètres requis
+##
+
+if [ -z "${USER_LOGIN}" ] \
+    || [ -z "${API_KEY}" ] \
+    || [ -z "${SMSAPI_BASEURL}" ] \
+    || [ -z "${SMSAPI_SEND_ACTION}" ] \
+; then
+    echo "ERROR: Either USER_LOGIN, API_KEY, SMSAPI_BASEURL or " \
+         "SMSAPI_SEND_ACTION is not set" >&2
+    exit 2
+fi
+
+
 ##
 ## Traitement du message
 ##