Introduction

This is a script to spider the NAVADMIN messages from the MyNavy HR (formerly Navy Personnel Command) website to help identify and download NAVADMIN messages.

The idea will be to migrate from just downloading and syncing up messages to one day mirroring them with better search, maybe better formatting, maybe even auto-addition of appropriate hyperlinks. But for now only downloading and re-displaying the NAVADMINs works.

Setup

You need Perl 5 and the Mojolicious web framework installed to try this. Pretty much every Unix-like OS has Perl easily available, from there Mojolicious is self-contained and not too hard to install, either by using its own installer or from CPAN (I recommend CPAN Minus).

Run

Downloading NAVADMINs

After completing the setup above, you should be able to just run ./download-updated-navadmins.pl to update existing and download new NAVADMINs.

The first time the script is ever run, it will download all NAVADMINs it can find on the MyNavy HR website (though even in this case it will request the server only respond if the NAVADMIN has somehow changed).

Subsequently (based on whether a .has-run file is present) it will only check for NAVADMINs for the current year, and will use the timestamp of existing NAVADMIN files to re-download from the server if the NAVADMIN is changed.

The web application will provide a hyperlink to the original (official) source if the chosen hyperlink is provided in navadmin_meta.json. The download script does this by default but you have to remember to check the updated meta.json back into the repository.

Serving up NAVADMINs

You can run ./navadmin-viewer.pl daemon to run a simple Web server (also powered by Mojolicious) to list NAVADMINs and serve up individual NAVADMINs. It is pretty bare at this point but wouldn't be too hard to pretty up.

Please don't actually run this on a production website if you aren't familiar enough with Mojolicious to set it up, I haven't configured CSRF token support or client secret configs or running with hypnotoad or any of that fun stuff.

The resulting web server will by default run at localhost port 3000, i.e. this link. You can also simply run the script directly to show off which routes are configured (./navadmin-viewer.pl routes) or test the response of a given GET request without a browser (./navadmin-viewer.pl get /by-year/2019).

Containerizing the application

This repository contains a Dockerfile you can use to turn the application into a working container-based app.

Build

To build, run

docker build -t navadmin-viewer:latest .

You can replace the navadmin-viewer:latest with an appropriate image name and image version as you wish.

Run

To run a new container with the image you just built, run

docker run -P --rm -it navadmin-viewer:latest

The -P switch allows docker to expose port 3000 in the container (where the web app will be expecting traffic) to a randomly-generated port that docker will choose. You can run docker ps to find out what the external port will be, or there's probably a better way to set the port by reading the docker-run documentation.

docker ps will also tell you the name of the new container. Run docker stop $name (where $name is the name as listed by docker ps) to stop the application.

Once you have a working container then getting it published and available to the wider world can be done using the vast array of platform services that are now available, including AWS, Azure, Google, Fly and probably a hundred others.

Auxiliary NAVADMIN admin

Some other scripts are popping up in this repo to help with cleaning up and parsing the downloaded NAVADMIN messages.

NAVADMIN Cleansing

These scripts are used when building the Docker container immediately prior to deployment. The changes they make are performed each deployment without updating the file in the git repository and without making textual changes to the NAVADMINs themselves.

• check-file-miscoded.pl -- reads in a list of files and then writes out a message if any character set issues are present.
• gen-miscoded-files-list -- A shell script using check-file-miscoded.pl against all downloaded NAVADMINs
• fix-miscoded-files -- A shell script reading in a list of files and a specific issue and then updating the file to correct the issue

This script makes minor edits to the NAVADMINs passed on the command line, or to all NAVADMINs if no specific files are mentioned, trying to correct obviously errorneous mistakes and simplify multiple possible forms for a message feature (e.g. GENTEXT/RMKS) into a single format for easier understanding later. This writes the result into a separate .ctxt file to avoid the potential for accidentally committing the result needlessly.

• clean-rmks.pl -- as above

NAVADMIN Parsing

I'm now working on a script that can read in a NAVADMIN and try to reformat it into a computer-readable form.

• split-msg.pl -- Reads in a NAVADMIN filename and prints out a JSON blob with the decoded contents of the NAVADMIN.

The JSON output of the above script is an object containing three fields:

1. head, a string with the newline-separated text of the NAVADMIN including all radio formatting codes.
2. body, a string with the newline-separated text of the NAVADMIN body, including other associated radio formatting (e.g. the BT at the end).
3. fields, an object containing best-effort decoding attempt at the fields in the header. All sub-fields that are read will be strings except for REF, which if present will be an array of objects.

• Each object in the REF array will have up to three entries:

  1. id, the REF ID as identified in the message (A, B, etc).
  2. `text, the remainder of the field, normally containing reference type, date, etc.
  3. ampn, "amplification", optional part of the message but normally has more info on what the reference is (e.g. NAVADMIN 142/18).

• build-reference-list.pl -- Walks through all NAVADMINs in the checked-out repo (preferring .ctxt versions over .txt versions) and reads in the references of each NAVADMIN to build a cross-reference tracker, which is output as JSON data. Debugging messages are output to STDERR. The same message reading library is used as for split-msg.pl.

Test Suite

A test suite can be run testing this script against the repository database of NAVADMIN messages, if the Perl "Test::Harness" module is installed. If so, you can run the prove command: prove -I modules -r, which recursively runs all modules under t/.

Testing impact of decoder script changes

If you have made uncommitted changes to the source code for the NAVADMIN parsing code (split-msg.pl or modules/MsgReader.pm) and want to see if it causes improper output or loss of previously-working detections, you can use some included scripts to make it easier to test.

The compare-output-changes script on Linux installs (with auxiliary tools jq, parallel installed) will output files out.txt and new.txt. Each file will contain a line for each NAVADMIN in the database along with a checksum for the output of the split-msg.pl script when run on that NAVADMIN. out.txt uses the output of the last Git commit, while new.txt uses the output of your currently uncommitted changes.

If the checksum in new.txt has changed from the same NAVADMIN in old.txt, then the changes may need to be looked at in more detail for that file.

The most important changes would be in field detection, so there is a dedicated script for that as well, compare-ref-field-changes, which requires compare-output-changes to have run first.

The script is very similar, except that instead of two files it generates two files for every NAVADMIN whose contents were not identical, under the out/ directory, and then shows a list of all changes. You can also do comparisons at the command line if you want to filter to a smaller list of changes.