Update dns_servercow.sh to support wildcard certs

Updated dns_servercow.sh to support txt records with multiple entries. This supports wildcard certificates that require txt records with the same name and different contents.

dnsapi/dns_servercow.sh

@@ -49,6 +49,30 @@ dns_servercow_add() {
   _debug _sub_domain "$_sub_domain"
   _debug _domain "$_domain"
   
+  # check whether a txt record already exists for the subdomain  
+  if printf -- "%s" "$response" | grep "{\"name\":\"$_sub_domain\",\"ttl\":20,\"type\":\"TXT\"" >/dev/null; then
+      _info "A txt record with the same name already exists."
+      # trim the string on the left
+      txtvalue_old=${response#*{\"name\":\"$_sub_domain\",\"ttl\":20,\"type\":\"TXT\",\"content\":\"}
+      # trim the string on the right
+      txtvalue_old=${txtvalue_old%%\"*}
+      
+      _debug txtvalue_old "$txtvalue_old"
+      
+      _info "Add the new txtvalue to the existing txt record."
+      if _servercow_api POST "$_domain" "{\"type\":\"TXT\",\"name\":\"$fulldomain\",\"content\":[\"$txtvalue\",\"$txtvalue_old\"],\"ttl\":20}"; then
+        if printf -- "%s" "$response" | grep "ok" >/dev/null; then
+          _info "Added additional txtvalue, OK"
+          return 0
+        else
+          _err "add txt record error."
+        return 1
+        fi
+      fi
+      _err "add txt record error."
+      return 1      
+    else
+      _info "There is no txt record with the name yet."
       if _servercow_api POST "$_domain" "{\"type\":\"TXT\",\"name\":\"$fulldomain\",\"content\":\"$txtvalue\",\"ttl\":20}"; then
         if printf -- "%s" "$response" | grep "ok" >/dev/null; then
           _info "Added, OK"
@@ -59,6 +83,8 @@ dns_servercow_add() {
         fi
       fi
       _err "add txt record error."
+      return 1
+  fi
   
   return 1
 }