This was a great explanation of Modified Preorder Tree Traversal (or MPTT): https://www.sitepoint.com/hierarchical-data-database-2/
A common use-case for MPTT is categorization data, like with the way django-oscar uses django-mptt: https://github.com/django-mptt/django-mptt
If you see this error in datatables: “Uncaught TypeError: Cannot read property ‘style’ of undefined”
It’s likely that you’re missing a header column in your table. Make sure you have the same number of <th> elements as items in the “columns” section of your datatables initialization.
This selectize.js library looks like a good replacement for Select2: selectize.js
This article has a lot of great lessons learned about timezones: Falsehoods programmers believe about time and time zones (archived)
If your changes to a JSON, JSONB, or HSTORE field aren’t saving after you commit, then you need to wrap your field in the MutableDict shown here: http://docs.sqlalchemy.org/en/latest/dialects/postgresql.html#sqlalchemy.dialects.postgresql.HSTORE
This error happened because I mistyped “db.column” instead of “db.Column” when I was creating my database model using SQLAlchemy.
This might be your problem if db.create_all() isn’t creating all the columns you expected.
Postgres has a couple of column types for semi-structured data, and Flask-Admin didn’t have a good way to edit them. I added support for both.
For HSTORE (Postgres key-value pairs), I reused the existing InlineFieldList and InlineFormField with a few changes (#1158). Instead of editing a raw string, you get a row of key/value inputs you can add to and remove from.
class ServerView(ModelView):
form_columns = ['name', 'metadata'] # metadata is an HSTORE column
For JSON columns, there was already a JSONField in the GeoAlchemy backend. I moved it into flask_admin/form/fields.py so both backends could use it, and made it handle non-ASCII characters and show a clear error on malformed JSON instead of blowing up (#1245).
Great article about the problems with using PHP for long running processes: software-gunslinger.tumblr.com/post/48215406921/php-is-meant-to-die-continued
Describes the main reason why I started using Python for long-running jobs.
When others are deploying a project for you, it’s easy for mistakes to be made when secrets must be updated in environmental variables. Ansible-vault takes a different approach and encrypts the secrets - allowing you to store the secrets in your repo.
To encrypt a file: ansible-vault encrypt secrets.py
To decrypt a file: ansible-vault decrypt secrets.py
More documentation is available here: https://docs.ansible.com/projects/ansible/latest/vault_guide/vault_encrypting_content.html