From fa98d72f3a87cf438ba16cccccf61fc268c517df Mon Sep 17 00:00:00 2001
From: RaidenII <ttzforj@hotmail.com>
Date: Tue, 27 Jun 2017 09:21:39 -0400
Subject: [PATCH] Added preliminary support for DuckDNS TXT record API, a free
 Dynamic DNS provider

---
 dnsapi/dns_duckdns.sh | 93 +++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 93 insertions(+)
 create mode 100755 dnsapi/dns_duckdns.sh

diff --git a/dnsapi/dns_duckdns.sh b/dnsapi/dns_duckdns.sh
new file mode 100755
index 00000000..dc0d49ca
--- /dev/null
+++ b/dnsapi/dns_duckdns.sh
@@ -0,0 +1,93 @@
+#!/usr/bin/env sh
+
+#Created by RaidenII, to use DuckDNS's API to add/remove text records
+#06/27/2017
+
+# Currently only support single domain access
+
+# DuckDNS uses StartSSL as their cert provider
+# Seems not supported natively on Linux
+# So I fall back to HTTP for API
+DuckDNS_API="http://www.duckdns.org/update"
+
+########  Public functions #####################
+
+#Usage: dns_duckdns_add _acme-challenge.domain.duckdns.org "XKrxpRBosdIKFzxW_CT3KLZNf6q0HG9i01zxXp5CPBs"
+dns_duckdns_add() {
+  fulldomain=$1
+  txtvalue=$2
+
+  # We'll extract the domain/username from full domain
+  IFS='.' read -r -a fqdn <<< "$fulldomain"
+  DuckDNS_domain="${fqdn[-3]}"
+
+  if [ -z "$DuckDNS_domain" ]; then
+    _err "Error extracting the domain."
+    return 1
+  fi
+
+  if [ -z "$DuckDNS_token" ]; then
+    DuckDNS_token=""
+    _err "The token for your DuckDNS account is necessary."
+    _err "You can look it up in your DuckDNS account."
+    return 1
+  fi
+
+  # Now save the credentials.
+  _saveaccountconf DuckDNS_domain "$DuckDNS_domain"
+  _saveaccountconf DuckDNS_token "$DuckDNS_token"
+
+  # Unfortunately, DuckDNS does not seems to support lookup domain through API
+  # So I assume your credentials (which are your domain and token) are correct
+  # If something goes wrong, we will get a KO response from DuckDNS
+
+  # Now add the TXT record to DuckDNS
+  _info "Trying to add TXT record"
+  if _duckdns_rest GET "domains=$DuckDNS_domain&token=$DuckDNS_token&txt=$txtvalue" && [ $response == "OK" ]; then
+    _info "TXT record has been successfully added to your DuckDNS domain."
+    _info "Note that all subdomains under this domain uses the same TXT record."
+    return 0
+  else
+    _err "Errors happened during adding the TXT record."
+    return 1
+  fi
+}
+
+#Usage: fulldomain txtvalue
+#Remove the txt record after validation.
+dns_duckdns_rm() {
+  fulldomain=$1
+  txtvalue=$2
+
+  # Now remove the TXT record from DuckDNS
+  _info "Trying to from TXT record"
+  if _duckdns_rest GET "domains=$DuckDNS_domain&token=$DuckDNS_token&txt=''&clear=true" && [ $response == "OK" ]; then
+    _info "TXT record has been successfully removed from your DuckDNS domain."
+    return 0
+  else
+    _err "Errors happened during removing the TXT record."
+    return 1
+  fi
+}
+
+####################  Private functions below ##################################
+
+#Usage: method  URI  data
+_duckdns_rest() {
+  method=$1
+  param="$2"
+  _debug param "$param"
+  url="$DuckDNS_API?$param"
+  _debug url "$url"
+
+  # DuckDNS uses GET to update domain info
+  if [ $method == "GET" ]; then
+    response="$(_get "$url")"
+  else
+    _err "Unsupported method"
+    return 1
+  fi
+
+  _debug response "$response"
+  return 0
+}