'str' object has no attribute 'items' using Django Rest Framework

Question

I have a working Django project and when I deploy it to my server I get this error:

AttributeError at /api/myData/

Django Version: 2.2.2

Exception Type: AttributeError Exception Value: 'str' object has no attribute 'items'

Exception Location: /pathToProject/lib/python3.7/site-packages/rest_framework/fields.py in to_representation, line 1729

On my local machine I am using Python3.6 but on the server I have 3.7. Requirements are the same.

Any idea why this happens?

settings.py file:

INSTALLED_APPS = [
    'django.contrib.admin',
    'django.contrib.auth',
    'django.contrib.contenttypes',
    'django.contrib.sessions',
    'django.contrib.messages',
    'django.contrib.staticfiles',

    'rest_framework',
    'corsheaders',

    ‘myapp’,
    ‘myapp2’,
]


MIDDLEWARE = [
    'corsheaders.middleware.CorsMiddleware',
    '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',
]


CORS_ORIGIN_ALLOW_ALL = True
CORS_ALLOW_CREDENTIALS = True
CORS_EXPOSE_HEADERS = (
    'Access-Control-Allow-Origin: *',
    'Access-Control-Allow-Methods: GET, POST, PUT, DELETE',
    'Access-Control-Allow-Headers: Authorization',

)

CORS_ORIGIN_WHITELIST = (
    'http://127.0.0.1:3000',
    'http://127.0.0.1:8000',
)

REST_FRAMEWORK = {
   'DEFAULT_PERMISSION_CLASSES': ('rest_framework.permissions.IsAdminUser',)
}

ROOT_URLCONF = ‘MyProject.urls'

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

WSGI_APPLICATION = 'MyProject.wsgi.application'

DATABASES = {
    'default': {
        'ENGINE': 'django.db.backends.postgresql',
        'NAME': ‘somedatabasename’,
        'USER': 'postgres',
        'PASSWORD': ’somepassword’,
        'HOST': 'localhost',
        'PORT': '5432',
    }
}


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',
    },
]


STATIC_URL = '/static/'

Answer 1

Adding

'django.contrib.postgres'

to

settings.INSTALLED_APPS

solved the problem. This happened because I was using an HStoreField which is a specific field in postgres.