1 files changed, 134 insertions, 0 deletions
diff --git a/dyndns.sh b/dyndns.sh
new file mode 100755
index 0000000..4847154
--- /dev/null
+++ b/dyndns.sh
@@ -0,0 +1,134 @@
+#! /bin/sh
+
+# Work with DigitalOcean api to update "A" and "AAAA" records for a domain.
+# Store DigitalOcean API token in file : DIGITALOCEAN_TOKEN 
+# Store domain to be updated in file : DIGITALOCEAN_DOMAIN 
+
+ip_version="$1"
+if [ -z "${ip_version:-}" ] || ([ "$ip_version" != 4 ] && [ "$ip_version" != 6 ]); then
+    echo "Error: no valid IP version provided" &>2
+    echo "Usage: dyndns.bash <4|6>" &>2
+    exit 1
+fi
+
+IP="$(./get_ip_addr.sh $ip_version)"
+if [ -z "$IP" ]; then
+    echo "Error: could not find IP address" &>2
+    exit 1
+fi
+
+SCRIPT="$0"
+SCRIPT_DIR=$(cd "${SCRIPT%/*}" && pwd )
+SCRIPT_NAME=${SCRIPT##*/}
+
+REPEAT_CHECK_DIR=$SCRIPT_DIR
+REPEAT_CHECK_A=$REPEAT_CHECK_DIR/REPEAT_CHECK_A
+REPEAT_CHECK_AAAA=$REPEAT_CHECK_DIR/REPEAT_CHECK_AAAA
+REPEAT_CHECK="$([ $ip_version = 4 ] && echo $REPEAT_CHECK_A || echo $REPEAT_CHECK_AAAA)"
+
+DIGITALOCEAN_DOMAIN=`cat $SCRIPT_DIR/DIGITALOCEAN_DOMAIN`
+DIGITALOCEAN_TOKEN=`cat $SCRIPT_DIR/DIGITALOCEAN_TOKEN`
+
+get_a_record_ids() {
+    curl -X GET \
+      -H "Content-Type: application/json" \
+      -H "Authorization: Bearer $DIGITALOCEAN_TOKEN" \
+      "https://api.digitalocean.com/v2/domains/$DIGITALOCEAN_DOMAIN/records" 2> /dev/null | jq '.domain_records |  map(select(.type == "A" and .name == "@")) | map(.id) | .[]'
+}
+
+get_aaaa_record_ids() {
+    curl -X GET \
+      -H "Content-Type: application/json" \
+      -H "Authorization: Bearer $DIGITALOCEAN_TOKEN" \
+      "https://api.digitalocean.com/v2/domains/$DIGITALOCEAN_DOMAIN/records" 2> /dev/null | jq '.domain_records |  map(select(.type == "AAAA" and .name == "@")) | map(.id) | .[]'
+}
+
+add_a_record() {
+    curl -X POST \
+      -H "Content-Type: application/json" \
+      -H "Authorization: Bearer $DIGITALOCEAN_TOKEN" \
+      -d "{\"type\":\"A\"         \
+          ,\"name\":\"@\"         \
+          ,\"data\":\"$IP\"       \
+          ,\"priority\":null      \
+          ,\"port\":null          \
+          ,\"ttl\":1800           \
+          ,\"weight\":null        \
+          ,\"flags\":null         \
+          ,\"tag\":null           \
+          }"                      \
+      "https://api.digitalocean.com/v2/domains/$DIGITALOCEAN_DOMAIN/records" 2> /dev/null | jq '.domain_record.id'
+}
+
+add_aaaa_record() {
+    curl -X POST \
+      -H "Content-Type: application/json" \
+      -H "Authorization: Bearer $DIGITALOCEAN_TOKEN" \
+      -d "{\"type\":\"AAAA\"         \
+          ,\"name\":\"@\"         \
+          ,\"data\":\"$IP\"       \
+          ,\"priority\":null      \
+          ,\"port\":null          \
+          ,\"ttl\":1800           \
+          ,\"weight\":null        \
+          ,\"flags\":null         \
+          ,\"tag\":null           \
+          }"                      \
+      "https://api.digitalocean.com/v2/domains/$DIGITALOCEAN_DOMAIN/records" 2> /dev/null | jq '.domain_record.id'
+}
+
+delete_record_by_id() {
+    echo deleting existing A/AAAA record for $DIGITALOCEAN_DOMAIN
+    curl -X DELETE \
+      -H "Content-Type: application/json" \
+      -H "Authorization: Bearer $DIGITALOCEAN_TOKEN" \
+      "https://api.digitalocean.com/v2/domains/$DIGITALOCEAN_DOMAIN/records/$1" > /dev/null 2>&1
+}
+
+replace_a_records() {
+    for id in `get_a_record_ids`; do
+        delete_record_by_id $id
+    done
+
+    new_record_id=`add_a_record`
+    if [ "$new_record_id" = "null" ] ; then
+        echo unable to add new A record for $DIGITALOCEAN_DOMAIN with value: $IP
+        return 1
+    fi
+    echo added new A record for $DIGITALOCEAN_DOMAIN with value: $IP
+}
+
+
+replace_aaaa_records() {
+    for id in `get_aaaa_record_ids`; do
+        delete_record_by_id $id
+    done
+
+    new_record_id=`add_aaaa_record`
+    if [ "$new_record_id" = "null" ] ; then
+        echo unable to add new AAAA record for $DIGITALOCEAN_DOMAIN with value: $IP
+        return 1
+    fi
+    echo added new AAAA record for $DIGITALOCEAN_DOMAIN with value: $IP
+}
+
+replace_records() {
+    [ $ip_version = 4 ] && replace_a_records || replace_aaaa_records
+}
+
+# exit if previous successful call was with same argument
+if [ -e $REPEAT_CHECK ]; then
+    PREVIOUS_IP=`cat $REPEAT_CHECK`
+    if [ "$IP" =  "$PREVIOUS_IP" ]; then
+        echo previous update was also with argument: \"$IP\"  so exiting now to avoid duplicate work.
+        exit
+    fi
+fi
+
+# attempt to replace records and, if successful, save arguments to check against next time
+if replace_records $IP; then
+    # if successful then save arguments.
+    echo update worked so saving arguments \"$IP\" in $REPEAT_CHECK
+    mkdir -p $REPEAT_CHECK_DIR
+    echo "$IP" > $REPEAT_CHECK
+fi