A Frappe app is a python package that uses the Frappe framework. Frappe apps live in a directory called apps in the frappe-bench directory.

The default app frappe is a frappe app which acts as the framework for all apps. A Frappe app should have an entry in apps.txt.

Creating an App

Frappe ships with a boilerplate for a new app. To create a new app, run the following command from the frappe-bench directory.

$ bench new-app custom_app
INFO:bench.app:creating new app custom_app
App Title (default: Custom App):
App Description: Custom Frappe App
App Publisher: John Doe
App Email: custom@johndoe.com
App Icon (default 'octicon octicon-file-directory'):
App Color (default 'grey'):
App License (default 'MIT'):
'custom_app' created at /Users/johndoe/frappe-bench/apps/custom_app
INFO:bench.app:installing custom_app
INFO:bench.utils:./env/bin/pip install -q  -e ./apps/custom_app

The custom_app directory will now be created in the apps directory. It will also be added to apps.txt.

Directory structure

The directory structure of the app will look something like this:

apps/custom_app
├── MANIFEST.in
├── README.md
├── custom_app
│  ├── __init__.py
│  ├── config
│  │  ├── __init__.py
│  │  ├── desktop.py
│  │  └── docs.py
│  ├── custom_app
│  │  └── __init__.py
│  ├── hooks.py
│  ├── modules.txt
│  ├── patches.txt
│  ├── public
│  │  ├── css
│  │  └── js
│  ├── templates
│  │  ├── __init__.py
│  │  └── includes
│  └── www
├── custom_app.egg-info
│  ├── PKG-INFO
│  ├── SOURCES.txt
│  ├── dependency_links.txt
│  ├── not-zip-safe
│  ├── requires.txt
│  └── top_level.txt
├── license.txt
├── requirements.txt
├── dev-requirements.txt
├── package.json
└── setup.py

requirements.txt

This file stores the list of python dependencies. When this app is installed, it's dependencies will also get installed.

dev-requirements.txt [Optional]

This file stores the list of python development dependencies. Syntax of this file is same as requirements.txt. If developer mode is enabled, then installing the app will also install its development dependencies.

package.json

This file is used to keep track of node dependencies. Learn more about it here.

custom_app

This is the directory where the source files are stored.

custom_app/custom_app

When you create a new app, a module with the same name is also created within the app. This is the directory which corresponds to that module.

custom_app/hooks.py

This file is used to hook into frappe events and extend or override standard behaviour by frappe.

Learn more about hooks.

custom_app/modules.txt

Every frappe app is organized into different modules. Every DocType is part of a module. These modules are listed in this file.

Learn more about modules.

custom_app/patches.txt

This file is used to store references to patches that run in database migrations. These patches are run in order, and they are run only once.

Learn more about Database Migrations.

custom_app/public

The public folder is a static folder and can be served by nginx in production. Files put here can be accessed via the url /assets/custom_app/**/*.

For example, the file public/img/logo.png is accessible via the url /assets/custom_app/img/logo.png.

This folder is used to store static assets used directly in the client side like JS, CSS and Images.

custom_app/templates

The templates folder is used to write and manage Jinja Templates. They can be organized in any way you want. This directory is directly scanned when you use them in Jinja templates.

For example, when you include a partial {% include "templates/navbar/navbar.html" %}, it will first scan this directory and then fallback to other apps.

custom_app/www

Files in this directory are directly mapped to portal pages and the URLs match the directory structure.

Learn more about portal pages.

Installing an app into a site

To use an app, it must be installed on a site. Installing an app on a site means creating the models that are bundled with the app into the site, which means creating database tables in the site database.

To install an app onto a site, run the following command:

$ bench --site site_name install-app custom_app

Installing custom_app...

To check whether the app was installed correctly, run the following command:

$ bench --site site_name list-apps
frappe
custom_app