Deploy a Django app as a client on laptop that is offline and sync the data with your server when you get back online.
pip install git+https://github.com/botswana-harvard/edc-sync@develop#egg=edc_sync
Add the pattern for access to the REST API:
urlpatterns = [
url(r'^edc-sync/', include('edc_sync.urls')),
)
In settings.py:
INSTALLED_APPS = [
...
'edc_sync.apps.AppConfig',
...]
###Configure a model for synchronization
To include a model for synchronization declare the model with BaseUuidModel from edc-base, define the natural_key method and the model manager method get_by_natural_key and add the HistoricalRecords manager from edc-base.
For example the base class for all CRFs in a module might look like this:
from edc_base.model.models import BaseUuidModel, HistoricalRecords
from .visit import Visit
class CrfModel(BaseUuidModel):
visit = models.OneToOneField(Visit)
objects = CrfModelManager()
history = HistoricalRecords()
def natural_key(self):
return (self.visit.natural_key(), )
natural_key.dependencies = ['myapp.visit']
class Meta:
abstract = True
In your app, add module sync_models.py.
# sync_models.py
from edc_sync.site_sync_models import site_sync_models
from edc_sync.sync_model import SyncModel
sync_models = [
'my_app.CrfModel',
]
site_sync_models.register(sync_models, SyncModel)
to disable the SyncModelMixin add this to your settings.py
ALLOW_MODEL_SERIALIZATION = False # (default: True)
from edc_sync.site_sync_models import site_sync_models
# list all models in app 'bcpp_household' set for sync
models = site_sync_models.site_models('bcpp_household', sync=True)
# list all models in app 'bcpp_household' NOT set for sync
models = site_sync_models.site_models('bcpp_household', sync=False)
# list all models in app 'bcpp_household' not set for sync, excluding the "historical" models
sync_models = [m.model._meta.label_lower for m in models if 'historical' not in m.model_name]
To create the model list for an apps sync_models.py, open a shell and list all models not yet registered for sync:
models = site_sync_models.site_models('bcpp_household', sync=False)
[m.model._meta.label_lower for m in models if 'historical' not in m.model_name]
Synchronization is one-way and always toward a central server that has the master database for the project. Many clients push data to one server.
We use edc-sync in Django apps deployed to low-resourced remote communities where there is no reliable internet, public or private network. Our Research Assistants collect participant data in households, mobile tents and remote clinics. The Research Assistants enter data directly into their offline laptops. Once back online, data is pushed to the community-server and later to the central-server.
Our research also involves collecting blood specimens that need to get to our community clinic within an hour or two from time of collection. Research Assistants stay out in the field on shift for 6 hours or more. So we send a driver to fetch specimens and data from the Research Assistant in the field. The driver has a middleman laptop that pulls all pending data from the Research Assistant's laptop. The driver and the Research Assistant then reconcile specimens and requisition data against the middleman data and the physical specimen. (Note: we requisition and label specimens in the field through the app). The driver then returns to the community clinic, pushes data onto the community-server and delivers all the specimens. The Lab Assistant then reconciles the specimens and requisition data against the community-server data and the physical specimen.
edc-sync uses either the REST API or FILE transfer:
- field client ---REST---> community server
- field client ---REST---> middleman (and modelre inspector) ---REST---> community server
- site server ---FILE---> central server