Test searching by closest color in Flask / Postgres.

Closest colors are calculated and sorted using the various Delta E (CIE Lab) color difference formulae.

By default, this app uses two Delta E formulae (the 1976 and the 2000 version) that are implemented as custom Postgres SQL functions. It can also be switched to use the python-colormath implementations, for baseline comparison of accuracy and performance.

Here's a demo of the app in action.

I've asked for help with improving the performance of the Delta E CIE 2000 SQL function on StackOverflow - suggestions welcome!

First, set your app's secret key as an environment variable. For example, add the following to .bashrc or .bash_profile.

export COLORSEARCHTEST_SECRET='something-really-secret'

Then run the following commands to bootstrap your environment.

git clone https://github.com/Jaza/colorsearchtest
cd colorsearchtest
pip install -r requirements/dev.txt
python manage.py server

You will see a pretty welcome screen.

You can have a different random secret key each time the app starts, if you want:

export COLORSEARCHTEST_SECRET=`python -c "import os; from binascii import hexlify; print(hexlify(os.urandom(24)))"`; python manage.py server

You can specify DB config when the app starts:

export COLORSEARCHTEST_DATABASE_URI="postgresql://colorsearchtest:colorsearchtest@localhost:5432/colorsearchtest"; python manage.py server

Once you have installed your DBMS, run the following if necessary (shouldn't be necessary), to set up the migrations:

python manage.py db init
python manage.py db migrate

Then, run the following to create your app's database tables and perform the initial migration:

python manage.py db upgrade
python manage.py server

To actually use colorsearchtest, you need to create a set of random colors in the database. To do this, run the following command, specifying a minimum and maximum number of colors to generate (of your choice), e.g:

python manage.py createcolors 900 1000

You can re-run this whenever you like. Each time you re-run it, the script will delete all existing colors and save new ones.

By default, the Delta E formulae to use are configured as follows:

IS_DELTA_E_COLORMATH_ENABLED = False
IS_DELTA_E_DBQUERY_ENABLED = True

These can be toggled by editing the colorsearchtest/settings.py file.

In your production environment, make sure the COLORSEARCHTEST_ENV environment variable is set to "prod".

To open the interactive shell, run

python manage.py shell

By default, you will have access to app and db.

To run all tests, run

python manage.py test

Whenever a database migration needs to be made. Run the following commands:

python manage.py db migrate

This will generate a new migration script. Then run:

python manage.py db upgrade

To apply the migration.

For a full migration command reference, run python manage.py db --help.