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Creating custom apps

Django Apps vs. Simmate Apps

Simmate is built on top of the Django web framework, which is used by thousands of developers. In fact, many major software companies & products were built using Django:

... and many more. Simmate is a very small addition to this list.

With this in mind, it is helpful to know that all of our Simmate apps are really just Django apps -- but with some extra features tacked on (e.g. chemistry tools & workflows). In fact, any app you build with Django can be used with Simmate. Because of this, we highly recommend exploring Django's intro guides to get started.

Step-by-Step Tutorials

  1. Django's official tutorial
  2. Simmate's getting-start guide

Tip

django is installed for you when you install simmate, so you can start their tutorials without any additional setup.

Folder Structure

All apps follow the same folder structure. While almost every folder is optional, we recommend using sub-folders (packages) for models and workflows once your app grows:

├── example_app
│   ├── command_line/    # custom CLI commands
│   ├── components/      # HTMX/UI components
│   ├── migrations/      # Database migrations
│   ├── models/          # Database tables
│   │   ├── __init__.py
│   │   ├── table_1.py
│   │   └── table_2.py
│   ├── schedules/       # periodic/timed tasks
│   ├── templates/       # HTML files
│   ├── workflows/       # Automated tasks
│   │   ├── __init__.py
│   │   ├── flow_1.py
│   │   └── flow_2.py
│   ├── config.py        # App configuration
│   ├── urls.py          # URL routing
│   └── views.py          # Web views

There are no restrictions on adding extra python modules to your app. In fact, some of our apps include extra functionality, such as inputs, outputs, or error_handlers.

Generate Example App Files

  1. To start a new app, navigate to your desired folder for code storage and run: 

    simmate start-project

  2. You will then see a new folder named my_simmate_project: 

    my_simmate_project/
├── pyproject.toml
├── README.md
└── example_app
    ├── __init__.py
    ├── config.py
    ├── models.py
    ├── tests.py
    ├── urls.py
    ├── views.py
    └── workflows.py

  3. Edit the files to start building out your new app

Tip

Once you get the hang of building apps, all of the code in these files will be annoying to go through & delete. There's nothing wrong with building your app out one file at a time, and ingoring the simmate start-project command.

Register Your App

Add your app's config to Simmate's list of registered apps:

simmate config add 'example_app.config.ExampleAppConfig'

Note

For Django users, all Simmate is doing here is adding your config to Simmate's internal list of Django INSTALLED_APPS

Adding Tables

You can add database tables (Django Models) to your app in two ways:

  1. A single file: Add your models directly to models.py.
  2. A folder: Create a models/ folder with an __init__.py and several sub-modules (e.g., structures.py, results.py).

If you use a folder, you must import your tables into models/__init__.py so Simmate can find them:

# in `my_app/models/__init__.py`
from .structures import MyStructureTable
from .results import MyTestResults

Note

Simmate uses the Django ORM to manage database tables, so all standard Django model rules apply.

Tip

Learn more about defining tables in our Database guides.

Adding Workflows

Similarly, you can organize your workflows as a single file or a folder:

  1. A single file: Add workflows to workflows.py and list them in the __all__ variable.
  2. A folder: Create a workflows/ folder with an __init__.py and several sub-modules.

If you use a folder, import your workflows into workflows/__init__.py:

# in `my_app/workflows/__init__.py`
from .relaxation import Relaxation__Vasp__MyCustom
from .static_energy import StaticEnergy__Vasp__MyCustom

Tip

Read more about building custom workflows in our Workflow guides.

Adding Web UI (urls/views)

Build your urls.py, views.py, and templates/ files following official Django docs.

We recommend following Django's best practice of namespacing your templates within a subfolder named after your app (e.g. my_app/templates/my_app/home.html). You should also extend Simmate's base template to get the standard styling and navbar:

{% extends "core_components/site_base.html" %}

{% block body %}
    <h1>Hello from My App!</h1>
{% endblock %}

Everything in your urls.py will be automatically mapped to a namespace matching your app's name. For example, if your app was called example_app and this was your urls.py:

from django.urls import path

from . import views

urlpatterns = [
    path('', views.index, name='index'),
    path('my-custom-view/', views.my_custom_view, name='custom'),
]

You could view them in the Simmate website at:

  • http://127.0.0.1:8000/apps/example_app/
  • http://127.0.0.1:8000/apps/example_app/my-custom-view/

Tip

Read more about custom views in our Website guides