##What is it?

Backdrop is a datastore built with Python and MongoDB. It is made up of two separately deployable APIs for reading and writing data over HTTP. The plan is to be able to gather data from a variety of sources and then aggregate and compare this data in useful ways.

• Data is grouped into buckets.
• Data is stored by posting json to the write api.
• Certain types of data are identified by reserved keys. ie events are objects containing a timestamp.
• Reserved keys start with an underscore. eg { "_timestamp": "2013-01-01T00:00:00Z }"
• Data is retrieved using http query strings on the read api.
• Data can be retrieved in a few useful ways. eg /<name_of_my_bucket>?period=month for monthly grouped data.
• Backdrop is in constant development, the best place to find examples and features are the feature tests

##Getting set up

This assumes you are using the GDS dev environment and so have python and mongo installed.

0. Check that you have virtualenv installed, if not sudo apt-get install python-virtualenv.
1. Navigate to this directory and run ./run_tests.sh. This will create a new virtualenv, install all dependencies and run the tests.
2. source venv/bin/activate to enable the virtualenv.
3. Copy backdrop/write/config/development_environment_sample.py to development_environment.py (if you want to) and edit as needed.

This is the OAuth flow we are using to authenticate users with Signonotron2

1. GET /_user/sign_in redirects user to signonotron2 asking them to give backdrop permission to see their data
2. User signs in allowing backdrop to see their data
3. GET (redirected from signonotron) /_user/authorized?code=blahblahblah
   • POST (to signonotron) /oauth/token exchanges authorization code for access token so backdrop can query users data
   • GET (to signonotron) /user.json uses access token to get user data and see if they have permissions to sign in to backdrop
4. User is now signed in

1. Clone the Sign-on-o-Tron II project
2. Use the rake tasks (bundle exec rake -T to list them) in order to create:
   1. A new application: bundle exec rake applications:create name=backdrop redirect_uri=http://backdrop-admin.dev.gov.uk/_user/authorized
   2. Edit development_environment.py to contain your OAuth consumer tokens from the previous step.
   3. A user: bundle exec rake users:create name=Test email=test@example.com applications=backdrop (then set the password etc)
3. Start backdrop_write and signon: bowl performance
4. Visit http://backdrop-admin.dev.gov.uk

Requests return a JSON object containing a data array.

GET /bucket_name will return an array of data. Each element is an object.

GET /bucket_name?collect=score&group_by=name will return an array. In this case, each element of the array is an object containing a name value, a score array with the scores for that name and a _count value with the number of scores.

GET /bucket_name?filter_by=name:Foo returns all elements with name equal to "Foo".

Other parameters:

• start_at (YYYY-MM-DDTHH:MM:SS+HH:MM) and end_at (YYYY-MM-DDTHH:MM:SS+HH:MM)
• period ("week", "month")
• sort_by (field)
• limit (number)