backend/settings.py

"""
Django settings for backend project.

Generated by 'django-admin startproject' using Django 5.2.7.

For more information on this file, see
https://docs.djangoproject.com/en/5.2/topics/settings/

For the full list of settings and their values, see
https://docs.djangoproject.com/en/5.2/ref/settings/
"""

import os
import sys
from pathlib import Path
from dotenv import load_dotenv

# Load environment variables from .env file
load_dotenv()

# Build paths inside the project like this: BASE_DIR / 'subdir'.
BASE_DIR = Path(__file__).resolve().parent.parent


# Quick-start development settings - unsuitable for production
# See https://docs.djangoproject.com/en/5.2/howto/deployment/checklist/

# SECURITY WARNING: keep the secret key used in production secret!
SECRET_KEY = os.environ.get("SECRET_KEY", "local-dev-secret")

# SECURITY WARNING: don't run with debug turned on in production!
DEBUG = os.environ.get("DEBUG", "True") == "True"

MODE = os.environ.get("BUILD_MODE", "development")

ALLOWED_HOSTS =[
    origin.strip()
    for origin in os.environ.get("ALLOWED_HOSTS", "").split(",")
    if origin.strip()
] if MODE == 'production' else []

CORS_ALLOW_CREDENTIALS = True
CORS_ALLOW_ALL_ORIGINS = False if MODE == 'production' else True


SESSION_COOKIE_HTTPONLY = True
SESSION_COOKIE_SECURE = True if MODE == 'production' else False # secure cookies only over HTTPS in production
SESSION_EXPIRE_AT_BROWSER_CLOSE = True
SESSION_COOKIE_AGE = 60 * 60 * 24  # 1 day

CSRF_COOKIE_HTTPONLY = True
CSRF_COOKIE_SECURE = True if MODE == 'production' else False
CSRF_TRUSTED_ORIGINS = [
    origin.strip()
    for origin in os.environ.get("CSRF_TRUSTED_ORIGINS", "").split(",")
    if origin.strip()
] if MODE == 'production' else [
	'http://localhost:5173',
	'http://localhost:4173',
	'http://localhost:3000'
	]

SECURE_SSL_REDIRECT = True if MODE == 'production' else False

SECURE_CONTENT_TYPE_NOSNIFF = True if MODE == 'production' else False

# HSTS settings - only enable in production with proper HTTPS configuration
# WARNING: Once enabled, browsers will remember this for SECURE_HSTS_SECONDS seconds
# Only enable after ensuring HTTPS works correctly for all domains
# Set to 0 to disable HSTS (default for development), or set a positive value (e.g., 31536000 for 1 year) for production
SECURE_HSTS_SECONDS = 31536000 if MODE == 'production' else 0
if MODE == 'production':
    SECURE_HSTS_INCLUDE_SUBDOMAINS = True
    SECURE_HSTS_PRELOAD = True


# Allow embedding in an iframe only from Hugging Face Spaces (for integration)
X_FRAME_OPTIONS = 'ALLOW-FROM https://huggingface.co/'
SECURE_PROXY_SSL_HEADER = ('HTTP_X_FORWARDED_PROTO', 'https')


# Application definition

INSTALLED_APPS = [
    'django.contrib.admin',
    'django.contrib.auth',
    'django.contrib.contenttypes',
    'django.contrib.sessions',
    'django.contrib.messages',
    'django.contrib.staticfiles',
    'rest_framework',
    'corsheaders',
    'agent_manager',
    'api',
]

MIDDLEWARE = [
    'django.middleware.security.SecurityMiddleware',
    'django.contrib.sessions.middleware.SessionMiddleware',
    'django.middleware.common.CommonMiddleware',
    'django.middleware.csrf.CsrfViewMiddleware',
    'django.contrib.auth.middleware.AuthenticationMiddleware',
    'django.contrib.messages.middleware.MessageMiddleware',
    'django.middleware.clickjacking.XFrameOptionsMiddleware',
    'corsheaders.middleware.CorsMiddleware',
]

ROOT_URLCONF = 'backend.urls'

TEMPLATES = [
    {
        'BACKEND': 'django.template.backends.django.DjangoTemplates',
        'DIRS': [],
        'APP_DIRS': True,
        'OPTIONS': {
            'context_processors': [
                'django.template.context_processors.request',
                'django.contrib.auth.context_processors.auth',
                'django.contrib.messages.context_processors.messages',
            ],
        },
    },
]

WSGI_APPLICATION = 'backend.wsgi.application'

# Database
# https://docs.djangoproject.com/en/5.2/ref/settings/#databases

DATABASES = {
    'default': {
        'ENGINE': 'django.db.backends.sqlite3',
        'NAME': BASE_DIR / 'db.sqlite3',
    }
}

CACHES = {
    "default": {
        "BACKEND": "django.core.cache.backends.locmem.LocMemCache",  # TODO: replace with Redis
        "LOCATION": "chatbot-cache",
    }
}

SESSION_ENGINE = 'django.contrib.sessions.backends.signed_cookies'
SESSION_CACHE_ALIAS = "default"

# Password validation
# https://docs.djangoproject.com/en/5.2/ref/settings/#auth-password-validators

AUTH_PASSWORD_VALIDATORS = [
    {
        'NAME': 'django.contrib.auth.password_validation.UserAttributeSimilarityValidator',
    },
    {
        'NAME': 'django.contrib.auth.password_validation.MinimumLengthValidator',
    },
    {
        'NAME': 'django.contrib.auth.password_validation.CommonPasswordValidator',
    },
    {
        'NAME': 'django.contrib.auth.password_validation.NumericPasswordValidator',
    },
]


# Internationalization
# https://docs.djangoproject.com/en/5.2/topics/i18n/

LANGUAGE_CODE = 'en-us'

TIME_ZONE = 'UTC'

USE_I18N = True

USE_TZ = True


# Static files (CSS, JavaScript, Images)
# https://docs.djangoproject.com/en/5.2/howto/static-files/

STATIC_URL = 'static/'

# Default primary key field type
# https://docs.djangoproject.com/en/5.2/ref/settings/#default-auto-field

DEFAULT_AUTO_FIELD = 'django.db.models.BigAutoField'

# RENDERER

REST_FRAMEWORK = {
    'DEFAULT_RENDERER_CLASSES': [
        'rest_framework.renderers.JSONRenderer',
    ]
}