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Useful information

TTL and general processing logic

MOWAS "Alert" and "Update" message types

mowas-pwb uses a decaying memory dictionary which will prevent message duplicates being sent to the user. The program's default life span for a messsage is 8 hours. If a MOWAS message (identified by its unique MOWAS message ID) has been sent to the user, it will enter this decaying dictionary. The same MOWAS message ID's content will be resent to the user if:

  • the MOWAS message ID is already present in the dictionary but changed its status (e.g. a message's status was changed from "Alert" to "Update")
  • the MOWAS message ID's is already present in the dictionary, its status in the dictionary AND in the current message is "Update" AND its update time stamp has changed. This indicates a message that was at least updated twice ("Alert" -> "Update" (1) --> "Update" (2))
  • the MOWAS message ID is NOT present in the dictionary AND its status is either "Alert" or "Update". We may never either have never encountered this message yet or it was already present in our dictionary but its entry has already expired. In that case, we will simply resend the message again and re-add the MOWAS message ID to our dictionary.

If at least one "Alert" or "Update" message has been detected during a program cycle which was deemed to be forwarded to the user, mowas-pwb will assume that there is an incident going on. The sleep interval will change from 60 to 15 mins (default settings), thus allowing the program to stay up to date with any ongoing changes.

MOWAS "Cancel" message type

Similar to the "Alert" and "Update" message types, mowas-pwb will handle "Cancel" messages in the following way:

  • If the MOWAS message ID is already present in the dictionary and its status has changed from "Alert"/"Update" to "Cancel", mowas-pwb will send out a cancel message to the user for one last time. The MOWAS message ID is then removed from the decaying dictionary.
  • If the MOWAS message ID is NOT present in the dictionary AND its status is "Cancel", the program will ignore this message. The MOWAS interface has no official documentation and it is unknown for how long a "Cancel" message will be present in the data stream. Rather than re-sending "Cancel" messages over and over, the program will ignore these cases.

The potential side effect for this constraint is that if you start the program and there is a MOWAS "Cancel" message for your watch area(s), you will not receive a message by the program. You WOULD have received one if that area had either been in "Alert" or "Update" status, though. Anyway, as the imminent danger is over, that cancellation message will no longer be sent to the user.

Known issues

  • In order to match with a given watch area, the user's coordinates (mowas_watch_areas from the program config file) have either to be inside of the given polygon or intersect with it.
  • Currently, there is no option that enables the user to specify and additional proximity to that polygon ("Polygon plus 10km distance")
  • This program uses native MOWAS data. All warning messages are in German. However, you can activate an auto-translation for these messages (via deepl). The translated content will be displayed in addition to the original German text (Email, Telegram) which should make it easier for German citizens to help you in case of emergencies. Due to the lack of UTF-8 support, SMS messages will be rendered as plain ASCII.
  • As the MOWAS APIs are not officially available to end users, government authorities might either terminate the services without notice and / or change the format settings of the services that are currently exposed (but not officially available to end users)
  • There is no message dupe check on a content level; if the same message is present in more than one MOWAS category and mowas-pwb deemed this message to be valid for your coordinates and program parameters' selection, you may receive that message more than once - unless the MOWAS government feed provides the message with the same unique identifier.

Have a look at the legal information