edc-device 0.2.6

Get info on a data collection device for clinicedc/edc

# edc-device

[](https://travis-ci.org/clinicedc/edc-device) [](https://coveralls.io/github/clinicedc/edc-device?branch=develop)

`edc-device` provides device roles unique device IDs for hosts and clients where the hostname may not be reliable. Hosts can be group as servers, clients, node_servers and some of their functionality limited according to this role.

A unique device ID is used to seed unique subject and sample identifiers. Uniqueness is evaluated during deployment.

Device information is set in and read from `edc_device.apps.AppConfig`.

You should subclass into your projects `apps.py` like this, for example:

from edc_device.apps import AppConfig as EdcDeviceAppConfigParent

class EdcDeviceAppConfig(EdcDeviceAppConfigParent):
device_id = '32'
device_role = CLIENT
device_permissions = DevicePermissions(
plot_add, plot_change, ...)

... and then in your settings:

INSTALLED_APPS = [
...
my_app.apps.EdcDeviceAppConfig,
myapp.apps.AppConfig',
]

Include in your `urls.py`:

urlpatterns = [
...
path('edc_device/', include('edc_device.urls')),
...
]

To get to the Edc Device home page, reverse the url like this:

reverse('edc_device:home_url')


## Usage


A `client` might look like this:

class EdcDeviceAppConfig(EdcDeviceAppConfigParent):
device_id = '18'
node_server_id_list = [97, 98, 99]
middleman_id_list = [95, 96]

>>> from django.apps import apps as django_apps
>>> app_config = django_apps.get_app_config('edc_device')
>>> app_config.device_id
'18'
>>> app_config.is_client
True
>>> app_config.device_role
'Client'

A node server server might look like this:

class EdcDeviceAppConfig(EdcDeviceAppConfigParent):
device_id = '98'
node_server_id_list = [97, 98, 99]
middleman_id_list = [95, 96]

>>> from django.apps import apps as django_apps
>>> app_config = django_apps.get_app_config('edc_device')
>>> app_config.device_id
'98'
>>> app_config.is_node_server
True
>>> app_config.device_role
'NodeServer'

A middleman server might look like this:

class EdcDeviceAppConfig(EdcDeviceAppConfigParent):
device_id = '95'
node_server_id_list = [97, 98, 99]
middleman_id_list = [95, 96]

>>> from django.apps import apps as django_apps
>>> app_config = django_apps.get_app_config('edc_device')
>>> app_config.device_id
'95'
>>> app_config.is_middleman
True
>>> app_config.device_role
'Middleman'

The central server might look like this:

class EdcDeviceAppConfig(EdcDeviceAppConfigParent):
device_id = '99'
node_server_id_list = [97, 98, 99]
middleman_id_list = [95, 96]

>>> from django.apps import apps as django_apps
>>> app_config = django_apps.get_app_config('edc_device')
>>> app_config.device_id
'99'
>>> app_config.is_middleman
True
>>> app_config.device_role
'CentralServer'


See also `edc_sync`.


## Device Permissions by Model

You can use the device role, or the device ID, to limit ADD/CHANGE permissions on a model.

`edc-device` AppConfig maintains a collection of `DeviceAddPermission` and `DeviceChangePermission` instances that are inspected in the `save` method of a model using the `DeviceModelMixin`.

To declare a `DeviceAddPermission` object:

test_model_add = DeviceAddPermission(
model='my_app.mymodel, device_roles=[NODE_SERVER, CENTRAL_SERVER])

To declare a `DeviceChangePermission` object:

test_model_change = DeviceChangePermission(
model='my_app.mymodel, device_roles=[CLIENT])

This means that if `app_config.device_role` is anything other than `NODE_SERVER` or `CENTRAL_SERVER`, the save method will raise a `DevicePermissionsAddError`.

To register the instances with `edc_device.apps.AppConfig.device_permissions`:

device_permissions = DevicePermissions(test_model_add, test_model_change)

This means that if `app_config.device_role` is anything other than `CLIENT`, the save method will raise a `DevicePermissionsChangeError`.

On boot up you should see:

Loading Edc Device ...
* device id is '10'.
* device role is 'Client'.
* device permissions exist for:
- edc_device.testmodel ADD NodeServer,CentralServer
- edc_device.testmodel CHANGE Client
Done loading Edc Device.

Models declared with the `EdcDeviceModelMixin` check the device permissions collection on save. Note the model mixin is already declared with `BaseUuidModel`.

from edc_base.model_mixins import BaseUuidModel

class TestModel(BaseUuidModel):
pass


### Declaring device permissions directly on model `Meta` class:

You can declare device permissions on `Meta.device_permissions` in the same way as above.

[...]
class Meta(DeviceModelMixin.Meta):
device_permissions = DevicePermissions(...)

Both `Meta` and `AppConfig` device permissions will be called, where the `Meta` class object will be called first.

### Disable device permissions by model instance:

You can disable device permissions _per model instance_ by setting `check_device_permissions` to `False`


### Customizing Device Permissions

The ADD and CHANGE device permission objects by default inspect the model's `id`. If `obj.id` is `None`, it as an ADD model operation; If `obj.id` is not `None`, it is a CHANGE model operation.

You can change this by overriding the `model_operation` method. The `model_operation` must return `None` or some value, such as `self.label`.

For example:

# default for DeviceAddPermission
label = 'ADD'

def model_operation(self, model_obj=None, **kwargs):
if not model_obj.id:
return self.label
return None

# overridden
def model_operation(self, model_obj=None, **kwargs):
"""Return ADD if both id and plot identifier are None.
"""
if not model_obj.id and not obj.plot_identifier:
return self.label
return None