✨ add DynDNS2 support for noip.com

♻️ do some shellcheck fixes

.gitchangelog.rc

@@ -0,0 +1,295 @@
+# -*- coding: utf-8; mode: python -*-
+##
+## Format
+##
+##   ACTION: [AUDIENCE:] COMMIT_MSG [!TAG ...]
+##
+## Description
+##
+##   ACTION is one of 'chg', 'fix', 'new'
+##
+##       Is WHAT the change is about.
+##
+##       'chg' is for refactor, small improvement, cosmetic changes...
+##       'fix' is for bug fixes
+##       'new' is for new features, big improvement
+##
+##   AUDIENCE is optional and one of 'dev', 'usr', 'pkg', 'test', 'doc'
+##
+##       Is WHO is concerned by the change.
+##
+##       'dev'  is for developpers (API changes, refactors...)
+##       'usr'  is for final users (UI changes)
+##       'pkg'  is for packagers   (packaging changes)
+##       'test' is for testers     (test only related changes)
+##       'doc'  is for doc guys    (doc only changes)
+##
+##   COMMIT_MSG is ... well ... the commit message itself.
+##
+##   TAGs are additionnal adjective as 'refactor' 'minor' 'cosmetic'
+##
+##       They are preceded with a '!' or a '@' (prefer the former, as the
+##       latter is wrongly interpreted in github.) Commonly used tags are:
+##
+##       'refactor' is obviously for refactoring code only
+##       'minor' is for a very meaningless change (a typo, adding a comment)
+##       'cosmetic' is for cosmetic driven change (re-indentation, 80-col...)
+##       'wip' is for partial functionality but complete subfunctionality.
+##
+## Example:
+##
+##   new: usr: support of bazaar implemented
+##   chg: re-indentend some lines !cosmetic
+##   new: dev: updated code to be compatible with last version of killer lib.
+##   fix: pkg: updated year of licence coverage.
+##   new: test: added a bunch of test around user usability of feature X.
+##   fix: typo in spelling my name in comment. !minor
+##
+##   Please note that multi-line commit message are supported, and only the
+##   first line will be considered as the "summary" of the commit message. So
+##   tags, and other rules only applies to the summary.  The body of the commit
+##   message will be displayed in the changelog without reformatting.
+
+
+##
+## ``ignore_regexps`` is a line of regexps
+##
+## Any commit having its full commit message matching any regexp listed here
+## will be ignored and won't be reported in the changelog.
+##
+ignore_regexps = [
+    r'@minor', r'!minor',
+    r'@cosmetic', r'!cosmetic',
+    r'@refactor', r'!refactor',
+    r'@wip', r'!wip',
+    r'^([cC]hg|[fF]ix|[nN]ew)\s*:\s*[p|P]kg:',
+    r'^([cC]hg|[fF]ix|[nN]ew)\s*:\s*[d|D]ev:',
+    r'^(.{3,3}\s*:)?\s*[fF]irst commit.?\s*$',
+    r'^$',  ## ignore commits with empty messages
+]
+
+
+## ``section_regexps`` is a list of 2-tuples associating a string label and a
+## list of regexp
+##
+## Commit messages will be classified in sections thanks to this. Section
+## titles are the label, and a commit is classified under this section if any
+## of the regexps associated is matching.
+##
+## Please note that ``section_regexps`` will only classify commits and won't
+## make any changes to the contents. So you'll probably want to go check
+## ``subject_process`` (or ``body_process``) to do some changes to the subject,
+## whenever you are tweaking this variable.
+##
+section_regexps = [
+    ('New', [
+        r'^:sparkles\s*:\s*((dev|use?r|pkg|test|doc)\s*:\s*)?([^\n]*)$',
+     ]),
+    ('Changes', [
+        r'^:wrench\s*:\s*((dev|use?r|pkg|test|doc)\s*:\s*)?([^\n]*)$',
+     ]),
+    ('Fix', [
+        r'^:bug\s*:\s*((dev|use?r|pkg|test|doc)\s*:\s*)?([^\n]*)$',
+     ]),
+    ('Documentation', [
+        r'^:memo\s*:\s*((dev|use?r|pkg|test|doc)\s*:\s*)?([^\n]*)$',
+     ]),     
+    ('Remove', [
+        r'^:fire\s*:\s*((dev|use?r|pkg|test|doc)\s*:\s*)?([^\n]*)$',
+     ]),     
+
+    ('Other', None ## Match all lines
+     ),
+
+]
+
+
+## ``body_process`` is a callable
+##
+## This callable will be given the original body and result will
+## be used in the changelog.
+##
+## Available constructs are:
+##
+##   - any python callable that take one txt argument and return txt argument.
+##
+##   - ReSub(pattern, replacement): will apply regexp substitution.
+##
+##   - Indent(chars="  "): will indent the text with the prefix
+##     Please remember that template engines gets also to modify the text and
+##     will usually indent themselves the text if needed.
+##
+##   - Wrap(regexp=r"\n\n"): re-wrap text in separate paragraph to fill 80-Columns
+##
+##   - noop: do nothing
+##
+##   - ucfirst: ensure the first letter is uppercase.
+##     (usually used in the ``subject_process`` pipeline)
+##
+##   - final_dot: ensure text finishes with a dot
+##     (usually used in the ``subject_process`` pipeline)
+##
+##   - strip: remove any spaces before or after the content of the string
+##
+##   - SetIfEmpty(msg="No commit message."): will set the text to
+##     whatever given ``msg`` if the current text is empty.
+##
+## Additionally, you can `pipe` the provided filters, for instance:
+#body_process = Wrap(regexp=r'\n(?=\w+\s*:)') | Indent(chars="  ")
+#body_process = Wrap(regexp=r'\n(?=\w+\s*:)')
+#body_process = noop
+body_process = ReSub(r'((^|\n)[A-Z]\w+(-\w+)*: .*(\n\s+.*)*)+$', r'') | strip
+
+
+## ``subject_process`` is a callable
+##
+## This callable will be given the original subject and result will
+## be used in the changelog.
+##
+## Available constructs are those listed in ``body_process`` doc.
+subject_process = (strip |
+    ReSub(r'^([cC]hg|[fF]ix|[nN]ew)\s*:\s*((dev|use?r|pkg|test|doc)\s*:\s*)?([^\n@]*)(@[a-z]+\s+)*$', r'\4') |
+    SetIfEmpty("No commit message.") | ucfirst | final_dot)
+
+
+## ``tag_filter_regexp`` is a regexp
+##
+## Tags that will be used for the changelog must match this regexp.
+##
+tag_filter_regexp = r'^[0-9]+\.[0-9]+(\.[0-9]+)?$'
+
+
+## ``unreleased_version_label`` is a string or a callable that outputs a string
+##
+## This label will be used as the changelog Title of the last set of changes
+## between last valid tag and HEAD if any.
+unreleased_version_label = "(unreleased)"
+
+
+## ``output_engine`` is a callable
+##
+## This will change the output format of the generated changelog file
+##
+## Available choices are:
+##
+##   - rest_py
+##
+##        Legacy pure python engine, outputs ReSTructured text.
+##        This is the default.
+##
+##   - mustache(<template_name>)
+##
+##        Template name could be any of the available templates in
+##        ``templates/mustache/*.tpl``.
+##        Requires python package ``pystache``.
+##        Examples:
+##           - mustache("markdown")
+##           - mustache("restructuredtext")
+##
+##   - makotemplate(<template_name>)
+##
+##        Template name could be any of the available templates in
+##        ``templates/mako/*.tpl``.
+##        Requires python package ``mako``.
+##        Examples:
+##           - makotemplate("restructuredtext")
+##
+#output_engine = rest_py
+#output_engine = mustache("restructuredtext")
+output_engine = mustache("markdown")
+#output_engine = makotemplate("restructuredtext")
+
+
+## ``include_merge`` is a boolean
+##
+## This option tells git-log whether to include merge commits in the log.
+## The default is to include them.
+include_merge = True
+
+
+## ``log_encoding`` is a string identifier
+##
+## This option tells gitchangelog what encoding is outputed by ``git log``.
+## The default is to be clever about it: it checks ``git config`` for
+## ``i18n.logOutputEncoding``, and if not found will default to git's own
+## default: ``utf-8``.
+#log_encoding = 'utf-8'
+
+
+## ``publish`` is a callable
+##
+## Sets what ``gitchangelog`` should do with the output generated by
+## the output engine. ``publish`` is a callable taking one argument
+## that is an interator on lines from the output engine.
+##
+## Some helper callable are provided:
+##
+## Available choices are:
+##
+##   - stdout
+##
+##        Outputs directly to standard output
+##        (This is the default)
+##
+##   - FileInsertAtFirstRegexMatch(file, pattern, idx=lamda m: m.start())
+##
+##        Creates a callable that will parse given file for the given
+##        regex pattern and will insert the output in the file.
+##        ``idx`` is a callable that receive the matching object and
+##        must return a integer index point where to insert the
+##        the output in the file. Default is to return the position of
+##        the start of the matched string.
+##
+##   - FileRegexSubst(file, pattern, replace, flags)
+##
+##        Apply a replace inplace in the given file. Your regex pattern must
+##        take care of everything and might be more complex. Check the README
+##        for a complete copy-pastable example.
+##
+# publish = FileInsertIntoFirstRegexMatch(
+#     "CHANGELOG.rst",
+#     r'/(?P<rev>[0-9]+\.[0-9]+(\.[0-9]+)?)\s+\([0-9]+-[0-9]{2}-[0-9]{2}\)\n--+\n/',
+#     idx=lambda m: m.start(1)
+# )
+#publish = stdout
+
+
+## ``revs`` is a list of callable or a list of string
+##
+## callable will be called to resolve as strings and allow dynamical
+## computation of these. The result will be used as revisions for
+## gitchangelog (as if directly stated on the command line). This allows
+## to filter exaclty which commits will be read by gitchangelog.
+##
+## To get a full documentation on the format of these strings, please
+## refer to the ``git rev-list`` arguments. There are many examples.
+##
+## Using callables is especially useful, for instance, if you
+## are using gitchangelog to generate incrementally your changelog.
+##
+## Some helpers are provided, you can use them::
+##
+##   - FileFirstRegexMatch(file, pattern): will return a callable that will
+##     return the first string match for the given pattern in the given file.
+##     If you use named sub-patterns in your regex pattern, it'll output only
+##     the string matching the regex pattern named "rev".
+##
+##   - Caret(rev): will return the rev prefixed by a "^", which is a
+##     way to remove the given revision and all its ancestor.
+##
+## Please note that if you provide a rev-list on the command line, it'll
+## replace this value (which will then be ignored).
+##
+## If empty, then ``gitchangelog`` will act as it had to generate a full
+## changelog.
+##
+## The default is to use all commits to make the changelog.
+#revs = ["^1.0.3", ]
+#revs = [
+#    Caret(
+#        FileFirstRegexMatch(
+#            "CHANGELOG.rst",
+#            r"(?P<rev>[0-9]+\.[0-9]+(\.[0-9]+)?)\s+\([0-9]+-[0-9]{2}-[0-9]{2}\)\n--+\n")),
+#    "HEAD"
+#]
+revs = []

.gitignore

@@ -0,0 +1 @@
+.env*

CHANGELOG.md

@@ -0,0 +1,36 @@
+# Changelog
+
+
+## (unreleased)
+
+### New
+
+* :sparkles: add interpretaton of status codes and act accordingly. [Eduard Veit]
+
+* :sparkles: make network interface configurable. [Eduard Veit]
+
+* :sparkles: add DynDNS2 support for dynv6.com. [Eduard Veit]
+
+* :sparkles: add .gitchangelog.rc. [Eduard Veit]
+
+* :sparkles: add dynb. [Eduard Veit]
+
+### Fix
+
+* :bug: fix sourcing of config file. [Eduard Veit]
+
+  :recycle: do some shellcheck fixes
+
+### Documentation
+
+* :memo: add CHANGELOG.md. [Eduard Veit]
+
+* :memo: add .env.example. [Eduard Veit]
+
+* :memo: write README.md. [Eduard Veit]
+
+### Other
+
+* Initial commit. [EV21]
+
+

README.md

@@ -1,2 +1,110 @@
-# dynb
-dynb - dynamic DNS update script for bash
+# 🔃 DynB
+DynB - dynamic DNS update script, written in bash
+
+IPv4 (A) and IPv6 (AAAA) record updates are supported.
+<!-- TOC -->
+- [✨ Update Methods](#-update-methods)
+    - [APIs](#apis)
+    - [DynDNS2](#dyndns2)
+- [📦 Requirements](#-requirements)
+- [🚀 Installation](#-installation)
+- [⚙ Configuration](#-configuration)
+- [🏃 Run](#-run)
+- [⏰ Cron](#-cron)
+<!-- /TOC -->
+
+## ✨ Update Methods
+The following update methods are currently implemented:
+
+### APIs
+
+* INWX.com JSON-RPC-API  
+  Limitations:
+  - minimum TTL is 300 (5 minutes)
+
+### DynDNS2
+
+* INWX.com  
+* dynv6.com
+
+## 📦 Requirements
+
+* `curl` - The minimum requirement for running DynDNS2 operations
+
+essential for APIs:
+
+* `jq` - Command-line JSON processor
+
+optional requirement:
+
+* `getopt` for CLI parameter handling from [util-linux](https://pkgs.org/download/util-linux)
+
+## 🚀 Installation
+
+Download the latest release
+
+or simply clone this repo
+```
+git clone https://github.com/EV21/dynb.git
+```
+
+If you want to add the script to you PATH, run :point_down:
+```
+bash dynb.sh --link
+```
+This convenience function only works if `util-linux` is installed on your system.
+
+## ⚙ Configuration
+
+You can use a config in form of an `.env` file.
+Or if your system meets the relevant requirements you can use CLI parameters.
+
+Create `.env` in the app root directory or at `~/.local/share/dynb/.env`.
+```
+_dyn_domain=dyndns.example.com
+
+## service provider could be inwx
+_serviceProvider=inwx
+
+## update method options: domrobot, dyndns
+_update_method=domrobot
+
+## ip mode could be either: 4, 6 or dual for dualstack
+_ip_mode=dual
+
+## If you are using the DomRobot RPC-API enter your credentials for the web interface login here
+## If you are using the DynDNS2 protocol enter your credentials here
+_username=
+_password=
+```
+
+## 🏃 Run
+
+If you have a config file just run :point_down:
+```
+dynb
+```
+Alternatively you can use parameters if your system meets the relevant requirements. This example shows the long form parameter, there are also short ones.  
+Call the help function :point_down:
+```
+dynb --help
+```
+```
+dynb --ip-mode dualstack --update-method domrobot --domain dyndns.example.com --username user42 --password SuperSecretPassword
+```
+```
+dynb --ip-mode dualstack --update-method dyndns --provider inwx --domain dyndns.example.com --username user42 --password SuperSecretPassword
+```
+
+## ⏰ Cron
+To automatically call the script you can use cron.
+
+execute :point_down:
+```
+crontab -e
+```
+then enter :point_down: to run dynb every five minutes.
+```
+*/5 * * * * $HOME/.local/bin/dynb >> $HOME/.local/share/dynb/dynb-cron.log
+```
+Note, cron typically does not use the users PATH variable.

dynb.sh

@@ -0,0 +1,634 @@
+#!/usr/bin/env bash
+
+## Copyright (c) 2021 Eduard Veit
+## All rights reserved. This program and the accompanying materials
+## are made available under the terms of the MIT license
+## which accompanies this distribution, and is available at
+## https://opensource.org/licenses/MIT
+
+###################
+## Configuration ##
+###################
+
+_dyn_domain=
+
+## service provider could be inwx
+_serviceProvider=
+
+## update method options: domrobot, dyndns
+_update_method=
+
+## ip mode could be either: 4, 6 or dual for dualstack
+_ip_mode=
+
+## If you are using the DomRobot RPC-API enter your credentials for the web interface login here
+## If you are using the DynDNS2 protocol enter your credentials here
+_username=
+_password=
+## or use a token
+_token=
+
+ ## TTL (time to live) for the DNS record
+ ## This setting is only relevant for API based record updates (not DnyDNS2!)
+ ## minimum allowed TTL value by inwx is 300 (5 minutes)
+TTL=300
+
+## The IP-Check sites (some sites have different urls for v4 and v6)
+## Pro tip: use your own ip check server for privacy
+## it could be as simple as that... 
+## create an index.php with <?php echo $_SERVER['REMOTE_ADDR']; ?>
+_ipv4_checker=api64.ipify.org
+_ipv6_checker=api64.ipify.org
+
+## An exernal DNS check server prevents wrong info from local DNS servers/resolvers
+_DNS_checkServer=1.1.1.1
+
+## if you are actively using multiple network interfaces you might want to specify this
+## normally the default value is okay
+#_network_interface=eth0
+_network_interface=
+
+######################################################
+## You don't need to change the following variables ##
+_INWX_JSON_API_URL=https://api.domrobot.com/jsonrpc/
+_new_IPv4=
+_new_IPv6=
+_dns_records=
+_main_domain=
+_has_getopt=
+_is_IPv4_enabled=false
+_is_IPv6_enabled=false
+_interface_str=
+_status=
+_eventTime=0
+_errorCounter=0
+_response=
+_statusHostname=
+_statusUsername=
+_statusPassword=
+_version=0.0.1
+_userAgent="DynB/$_version github.com/EV21/dynb"
+_configFile=$HOME/.local/share/dynb/.env
+_statusFile=/tmp/dynb.status
+_debug=1
+
+_help_message="$(cat << 'EOF'
+dynb - dynamic DNS update script for bash
+
+Usage
+=====
+dynb [options]
+
+-h, --help                                displays this help message
+--version                                 outputs the client version
+--link                                    links to your script at ~/.local/bin/dynb
+--reset                                   deletes the client blocking status file
+
+Configuration options
+---------------------
+-i | --ip-mode [ 4 | 6 | dual ]           updates type A (IPv4) and AAAA (IPv6) records
+-m | --update-method [dyndns | domrobot]  choose if you want to use DynDNS2 or the DomRobot RPC-API
+-s | --service-provider inwx              set your provider in case you are using DynDNS2
+-d | --domain "dyndns.example.com"        set the domain you want to update
+-u | --username "user42"                  depends on your selected update method and your provider
+-p | --password "SuperSecretPassword"     depends on your selected update method and your provider
+-t | --token "YourProviderGivenToken"     depends on your selected update method and your provider
+
+##### examples #####
+dynb --ip-mode dual --update-method domrobot --domain dyndns.example.com --username user42 --password SuperSecretPassword
+dynb --ip-mode dual --update-method dyndns --service-provider inwx --domain dyndns.example.com --username user42 --password SuperSecretPassword
+EOF
+)"
+
+function debugMode() {
+  if [[ $_debug -eq 1 ]]; then
+    return 0
+  else
+    return 1
+  fi
+}
+
+function debugMessage() {
+  if debugMode; then
+    echo "Debug: ${1}"
+  fi
+}
+
+function echoerr() { printf "%s\n" "$*" >&2; }
+
+# The main domain as an identifier for the dns zone is required for the updateRecord call
+function getMainDomain() {
+  request=$( echo "{}" | \
+      jq '(.method="nameserver.list")' | \
+      jq "(.params.user=\"$_username\")" | \
+      jq "(.params.pass=\"$_password\")"
+    )
+
+  _response=$(curl --silent  \
+      "$_interface_str" \
+      --user-agent "$_userAgent" \
+      --header "Content-Type: application/json" \
+      --request POST $_INWX_JSON_API_URL \
+      --data "$request" | jq ".resData.domains[] | select(inside(.domain=\"$_dyn_domain\"))"
+    )
+  _main_domain=$( echo "$_response" | jq --raw-output '.domain'  )
+}
+
+function fetchDNSRecords() {
+  request=$( echo "{}" | \
+      jq '(.method="'nameserver.info'")' | \
+      jq "(.params.user=\"$_username\")" | \
+      jq "(.params.pass=\"$_password\")" | \
+      jq "(.params.domain=\"$_main_domain\")" | \
+      jq "(.params.name=\"$_dyn_domain\")"
+    )
+
+  _response=$( curl --silent  \
+      "$_interface_str" \
+      --user-agent "$_userAgent" \
+      --header "Content-Type: application/json" \
+      --request POST $_INWX_JSON_API_URL \
+      --data "$request"
+    )
+
+  _dns_records=$( echo "$_response" | jq '.resData.record[]' )
+}
+
+# requires parameter A or AAAA
+# result to stdout 
+function getRecordID() {
+  echo "$_dns_records" | jq "select(.type == \"${1}\") | .id"
+}
+
+# requires parameter A or AAAA
+# result to stdout
+function getDNSIP() {
+  echo "$_dns_records" | jq --raw-output "select(.type == \"${1}\") | .content"
+}
+
+# requires parameter
+# 1. param: 4 or 6 for ip version
+# 2. param: IP check server address
+# result to stdout
+function getRemoteIP() {
+  curl --silent "$_interface_str" --user-agent "$_userAgent" \
+    --ipv"${1}" --dns-servers 1.1.1.1 --location "${2}"
+}
+
+# requires parameter
+# 1. param: 4 or 6 as ip version
+function updateRecord() {
+  if [[ ${1} == 4 ]]; then
+    ID=$(getRecordID A)
+    IP=$_new_IPv4
+  fi
+  if [[ ${1} == 6 ]]; then
+    ID=$(getRecordID AAAA)
+    IP=$_new_IPv6
+  fi
+  if [[ $IP != "" ]]; then
+  request=$( echo "{}" | \
+      jq '(.method="nameserver.updateRecord")' | \
+      jq "(.params.user=\"$_username\")" | \
+      jq "(.params.pass=\"$_password\")" | \
+      jq "(.params.id=\"$ID\")" | \
+      jq "(.params.content=\"$IP\")" | \
+      jq "(.params.ttl=\"$TTL\")"
+    )
+
+  _response=$(curl --silent  \
+      "$_interface_str" \
+      --user-agent "$_userAgent" \
+      --header "Content-Type: application/json" \
+      --request POST $_INWX_JSON_API_URL \
+      --data "$request"
+     )
+     echo -e "$(echo "$_response" | jq --raw-output '.msg')\n Domain: $_dyn_domain\n new IPv${1}: $IP"
+  fi
+}
+
+# using DynDNS2 protocol
+function dynupdate() {
+  # default parameter values
+  myip_str=myip
+  myipv6_str=myipv6
+
+  INWX_DYNDNS_UPDATE_URL="https://dyndns.inwx.com/nic/update?"
+  NOIP_DYNDNS_UPDATE_URL="https://dynupdate.no-ip.com/nic/update?hostname=$_dyn_domain&"
+  DYNV6_DYNDNS_UPDATE_URL="https://dynv6.com/api/update?zone=$_dyn_domain&token=$_token&"
+
+  if [[ $_serviceProvider == "inwx" ]]; then
+    dyndns_update_url=$INWX_DYNDNS_UPDATE_URL
+  fi
+  if [[ $_serviceProvider == "noip" ]] || [[ $_serviceProvider == "no-ip" ]]; then
+    dyndns_update_url=$NOIP_DYNDNS_UPDATE_URL
+  fi
+  if [[ $_serviceProvider == "dynv6" ]]; then
+    dyndns_update_url="${DYNV6_DYNDNS_UPDATE_URL}"
+    myip_str=ipv4
+    myipv6_str=ipv6
+  fi
+
+  if [[ $_is_IPv4_enabled == true ]] && [[ $_is_IPv6_enabled == true ]]; then
+    dyndns_update_url="${dyndns_update_url}${myip_str}=${_new_IPv4}&${myipv6_str}=${_new_IPv6}"
+  fi
+  if [[ $_is_IPv4_enabled == true ]] && [[ $_is_IPv6_enabled == false ]]; then
+    dyndns_update_url="${dyndns_update_url}${myip_str}=${_new_IPv4}"
+  fi
+  if [[ $_is_IPv4_enabled == false ]] && [[ $_is_IPv6_enabled == true ]]; then
+    dyndns_update_url="${dyndns_update_url}${myipv6_str}=${_new_IPv6}"
+  fi
+  debugMessage "Update URL was: $dyndns_update_url"
+  ## request ##
+  if [[ $_serviceProvider == "dynv6" ]]; then
+    _response=$(curl --silent "$_interface_str" \
+        --user-agent "$_userAgent" \
+        "${dyndns_update_url}"
+      )
+  fi
+  if [[ $_serviceProvider == "inwx" || $_serviceProvider == "noip" ]]; then
+    _response=$(curl --silent "$_interface_str" \
+      --user-agent "$_userAgent" \
+      --user "$_username":"$_password" \
+      "${dyndns_update_url}" )
+  fi
+
+  case $_response in
+    good* )
+      if [[ $_response == "good 127.0.0.1" ]]; then
+        echoerr "Error: $_response: Request ignored."
+        return 1
+      else
+        echo "$_response: The DynDNS update has been executed."
+        _errorCounter=0
+        return 0
+      fi
+    ;;
+    nochg* )
+      echo "$_response: Nothing has changed, IP addresses are still up to date."
+      return 1
+    ;;
+    abuse )
+      echoerr "Error: $_response: Username is blocked due to abuse."
+      return 1
+    ;;
+    badauth | 401 )
+      echoerr "Error: $_response: Invalid username password combination."
+      return 1
+    ;;
+    badagent )
+      echoerr "Error: $_response: Client disabled. Something is very wrong!"
+      return 1
+    ;;
+    !donator )
+      echoerr "Error: $_response: An update request was sent, including a feature that is not available to that particular user such as offline options."
+      return 1
+    ;;
+    !yours )
+      echoerr "Error: $_response: The domain does not belong to your user account"
+      return 1
+    ;;
+    notfqdn )
+      echoerr "Error: $_response: Hostname $_dyn_domain is invalid"
+      return 1
+    ;;
+    nohost )
+      echoerr "Error: $_response: Hostname supplied does not exist under specified account, enter new login credentials before performing an additional request."
+      return 1
+    ;;
+    numhost )
+      echoerr "Error: $_response: Too many hostnames have been specified for this update"
+      return 1
+    ;;
+    dnserr )
+      echoerr "Error: $_response: There is an internal error in the dyndns update system. Retry update no sooner than 30 minutes."
+      return 1
+    ;;
+    911 | 5* )
+      echoerr "Error: $_response: A fatal error on provider side such as a database outage. Retry update no sooner than 30 minutes."
+      return 1
+    ;;
+    * )
+      if [[ "$_response" == "$_status" ]]; then
+        echoerr "Error: An unknown response code has been received. $_response"
+        return 1
+      else
+        echoerr "Error: unknown respnse code: $_response"
+        return 0
+      fi
+    ;;
+  esac
+}
+
+function setStatus() {
+  echo "_status=$1; _eventTime=$2; _errorCounter=$3; _statusHostname=$4; _statusUsername=$5; _statusPassword=$6" > /tmp/dynb.status
+}
+
+# handle errors from past update requests
+function checkStatus() {
+  case $_status in
+    nochg* )
+      if [[ _errorCounter -gt 1 ]]; then
+        echoerr "Error: The update client was spamming unnecessary update requests, something might be wrong with your IP-Check site."
+        echoerr "Fix your config an then delete $_statusFile"
+        return 1
+      fi
+    ;;
+    nohost | !yours )
+      if [[ "$_statusHostname" == "$_dyn_domain" && ( "$_statusUsername" == "$_username" || $_statusUsername == "$_token" ) ]]; then
+        echoerr "Error: Hostname supplied does not exist under specified account, enter new login credentials before performing an additional request."
+        return 1
+      else
+        rm "$_statusFile"
+      fi
+      return 0
+    ;;
+    badauth | 401 )
+      if [[ "$_statusUsername" == "$_username" && "$_statusPassword" == "$_password" ]]; then
+        echoerr "Error: Invalid username password combination."
+        return 1
+      else
+        rm "$_statusFile"
+      fi
+      return 0
+    ;;
+    badagent )
+      echoerr "Error: Client is deactivated by provider."
+      echo "Fix your config and then manually remove $_statusFile to reset the client blockade."
+      echo "If it still fails file an issue at github or try another client :)"
+      return 1
+    ;;
+    !donator )
+      echoerr "Error: An update request was sent, including a feature that is not available to that particular user such as offline options."
+      echo "Fix your config and then manually remove $_statusFile to reset the client blockade"
+      echo "If it still fails file an issue at github or try another client :)"
+      return 1
+    ;;
+    abuse )
+      echoerr "Error: Username is blocked due to abuse."
+      echo "Fix your config and then manually remove $_statusFile to reset the client blockade"
+      echo "If it still fails file an issue at github or try another client :)"
+      return 1
+    ;;
+    911 | 5* )
+      delta=$(( $(date +%s) - _eventTime ))
+      if [[ $delta -lt 1800 ]]; then
+        echoerr "$_status: The provider currently has an fatal error. DynB will wait for next update until 30 minutes have passed since last request, $(date --date=@$delta -u +%M) minutes already passed."
+        return 1
+      else
+        rm "$_statusFile"
+      fi
+      return 0
+    ;;
+    * )
+      if [[ _errorCounter -gt 1 ]]; then
+        echoerr "Error: An unknown response code has repeatedly been received. $_response"
+        return 1
+      else
+        return 0
+      fi
+    ;;
+  esac
+}
+
+# requires parameter
+# 1. param: 4 or 6 for IP version
+function ipHasChanged() {
+  if [[ ${1} == 4 ]]; then
+    remote_ip=$(getRemoteIP 4 $_ipv4_checker)
+    if [[ $_update_method == domrobot ]]; then
+      dns_ip=$(getDNSIP A)
+    else
+      dns_ip=$(dig @${_DNS_checkServer} in a +short "$_dyn_domain")
+    fi
+  fi
+  if [[ ${1} == 6 ]]; then
+    remote_ip=$(getRemoteIP 6 $_ipv6_checker)
+    if [[ $_update_method == domrobot ]]; then
+      dns_ip=$(getDNSIP AAAA)
+    else
+      dns_ip=$(dig @${_DNS_checkServer} in aaaa +short "$_dyn_domain")
+    fi
+  fi
+
+  if [[ ${1} == 4 ]]; then
+    _new_IPv4=$remote_ip
+    #echo "New IPv4: $_new_IPv4 old was: $dns_ip"
+  else
+    _new_IPv6=$remote_ip
+    #echo "New IPv6: $_new_IPv6 old was: $dns_ip"
+  fi
+
+  if [[ "$remote_ip" == "$dns_ip" ]]; then
+    return 0
+  else
+    return 1
+  fi
+}
+
+###############
+## arguments ##
+###############
+
+ARGS=
+if [[ $_has_getopt == "" ]] && [[ $(uname) == Linux ]]; then
+  ARGS=$(getopt --options "hvi:,d:,m:,s:,u:,p:,t:" --longoptions "help,version,link,ip-mode:,domain:,update-method:,service-provider:,username:,password:,token:,reset" -- "$@");
+fi
+eval set -- "$ARGS";
+unset ARGS
+
+function processParameters() {
+  while true; do
+    case $1 in
+      -h | --help )
+        echo "$_help_message"
+        exit 0
+        ;;
+      -v | --version )
+        echo "$_version"
+        exit 0
+        ;;
+      --link )
+        ln --verbose --symbolic "$(realpath "$0")" "$HOME/.local/bin/dynb"
+        exit 0
+        ;;
+      -i | --ip-mode )
+        _ip_mode=$2
+        shift 2
+        ;;
+      -d | --domain )
+        _dyn_domain=$2
+        shift 2
+        ;;
+      -m | --update-method )
+        _update_method=$2
+        shift 2
+        ;;
+      -s | --service-provider )
+        _serviceProvider=$2
+        shift 2
+        ;;
+      -u | --username )
+        _username=$2
+        shift 2
+        ;;
+      -p | --password )
+        _password=$2
+        shift 2
+        ;;
+      -t | --token )
+        _token=$2
+        shift 2
+        ;;
+      --reset )
+        rm --verbose "$_statusFile"
+        exit 0
+        ;;
+      --)
+        shift
+        break
+    esac
+  done
+}
+
+##################
+## dependencies ##
+##################
+
+function checkDependencies() {
+  ## If there will be more general dependencies use a loop
+  # for i in curl and some other stuff; do
+  #   if ! command -v $i >/dev/null 2>&1; then
+  #     echoerr "Error: could not find \"$i\", DynB depends on it. "
+  #     exit 1
+  #   fi
+  # done
+  [[ -x $(command -v jq 2> /dev/null) ]] || {
+    if [[ $_update_method != dyndns* ]]; then
+      echo "This script depends on jq and it is not available." >&2
+      exit 1
+    fi
+  }
+  # maybe replace this with matejak/argbash
+  [[ -x $(command -v getopt 2> /dev/null) ]] || {
+    _has_getopt=false
+  }
+}
+
+function doUnsets() {
+  unset _network_interface
+  unset _DNS_checkServer
+  unset _dns_records
+  unset _dyn_domain
+  unset _has_getopt
+  unset _help_message
+  unset _INWX_JSON_API_URL
+  unset _ip_mode
+  unset _ipv4_checker
+  unset _ipv6_checker
+  unset _is_IPv4_enabled
+  unset _is_IPv6_enabled
+  unset _main_domain
+  unset _new_IPv4
+  unset _new_IPv6
+  unset _password
+  unset _username
+  unset _serviceProvider
+  unset _version
+}
+
+#################
+## MAIN method ##
+#################
+function dynb() {
+  ## parameters and checks
+  checkDependencies
+
+  # shellcheck source=.env
+  if test -f "$_configFile"; then
+    # shellcheck disable=SC1091
+    source "$_configFile"
+  else
+    alternativeConfig="$(dirname "$(realpath "$0")")/.env"
+    if test -f "$alternativeConfig"; then
+      # shellcheck disable=SC1091
+      source "$alternativeConfig"
+    fi
+  fi
+  if test -f "$_statusFile"; then
+    debugMessage "read previous status file"
+    # shellcheck disable=SC1090
+    source "$_statusFile"
+  fi
+
+  if [[ $_has_getopt == "" ]] && [[ $(uname) == Linux ]]; then
+    processParameters "$@"
+  fi
+
+  if [[ $_network_interface != "" ]]; then
+    _interface_str="--interface $_network_interface"
+  fi
+
+  if [[ $_ip_mode == d* ]]; then
+    _is_IPv4_enabled=true
+    _is_IPv6_enabled=true
+  fi
+  if [[ $_ip_mode == *4* ]]; then
+    _is_IPv4_enabled=true
+  fi
+  if [[ $_ip_mode == *6* ]]; then
+    _is_IPv6_enabled=true
+  fi
+
+  ## execute operations
+
+  if [[ $_update_method == "domrobot" ]]; then
+    getMainDomain
+    fetchDNSRecords
+    if [[ $_is_IPv4_enabled == true ]]; then
+      ipHasChanged 4
+      if [[ $? == 1 ]]; then
+        updateRecord 4
+      fi
+    fi
+    if [[ $_is_IPv6_enabled == true ]]; then
+      ipHasChanged 6
+      if [[ $? == 1 ]]; then
+        updateRecord 6
+      fi
+    fi
+  fi
+
+  if [[ $_update_method == "dyndns" ]]; then
+    changed=0
+    if [[ $_is_IPv4_enabled == true ]]; then
+      ipHasChanged 4
+      (( changed += $? ))
+    fi
+    if [[ $_is_IPv6_enabled == true ]]; then
+      ipHasChanged 6
+      (( changed += $? ))
+    fi
+    if [[ $changed -gt 0 ]]; then
+      if checkStatus; then
+        debugMessage "checkStatus has no errors"
+        if dynupdate; then
+          debugMessage "DynDNS2 update success"
+        else
+          debugMessage "Save new status after dynupdate has failed"
+          setStatus "$_response" "$(date +%s)" $(( _errorCounter += 1 )) "$_dyn_domain" "${_username}${_token}"
+        fi
+      else
+        debugMessage "Skip DynDNS2 update, checkStatus fetched previous error."
+      fi
+    fi
+  fi
+  doUnsets
+  return 0
+}
+######################
+## END MAIN section ##
+######################
+
+  dynb "${@}"
+  exit $?

example.env

@@ -0,0 +1,7 @@
+_dyn_domain=dyndns.example.com
+_serviceProvider=inwx
+_update_method=domrobot
+_ip_mode=dual
+_username=User42
+_password=SuperSecretPassword
+_token=