Pagination of datapoints

[cdupont]

To help retrieving big amounts of sensor datapoints, we need to use a pagination mechanism.
We can use those query strings:

• vLastN: Only the requested last datapoints will be returned. Datapoints are sorted with the most recent datapoint first. It is on by default, with a value of 20.
• vLimit: In case of pagination, the number of datapoints per page.
• vOffset: In case of pagination, the offset to apply to the requested search of datapoints.
• vDateFrom: The starting date and time from which the datapoints are desired. It is an optional parameter.
• vDateTo: The final date and time until which the datapoints are desired. It is an optional parameter.

Example of query:

curl -X GET "http://dev.waziup.io:80/api/v1/domains/waziup/sensors/mySensor/measurements/TC/values?vLimit=50&vOffset=0&vDateFrom=2016-01-01T00:00:00.000Z&vDateTo=2016-01-31T23:59:59.999Z"

This query will retrieve the first 50 datapoints from January 2016.

[cdupont]

Note that Orion already have pagination:
https://github.com/telefonicaid/fiware-orion/blob/master/doc/manuals/user/pagination.md
This works for sensors and entities, but not datapoint as they are stored in Mongo.

[cdupont]

Done: 98e58e8

[cdupont]

@henokzion Could you validate and close this issue?

[henokzion]

It's working correctly

[cdupont]

@henokzion I extended the pagination mechanism to all GET endpoints in /sensors.
i.e.:
GET /domains/{domain}/sensors
GET /domains/{domain}/sensors/{sensor_id}
GET /domains/{domain}/sensors/{sensor_id}/measurements
GET /domains/{domain}/sensors/{sensor_id}/measurements/{measurement_id}
GET /domains/{domain}/sensors/{sensor_id}/measurements/{measurement_id}/values

The pagination will limit the number of datapoint returned.
@henokzion Could you test also?

[henokzion]

GET /domains/{domain}/sensors
for this request we could limit the pagination to the sensors themselves and show only the last values with the sensors.
GET /domains/{domain}/sensors/{sensor_id}
here also we could show the last value
GET /domains/{domain}/sensors/{sensor_id}/measurements
here also we could show the last value for each of the measurement
GET /domains/{domain}/sensors/{sensor_id}/measurements/{measurement_id}
here we could paginate the value of the given measurement

[cdupont]

OK great, I'll do that.

[cdupont]

This is what I did:

• GET /domains/{domain}/sensors
  • only limit, offset are applied to the list the sensors
  • only the last measurement value is returned
• GET /domains/{domain}/sensors/{sensor_id}
  • no pagination necessary
  • only the last measurement value is returned
• GET /domains/{domain}/sensors/{sensor_id}/measurements
  • no pagination necessary
  • only the last measurement value is returned
• GET /domains/{domain}/sensors/{sensor_id}/measurements/{measurement_id}
  • no pagination necessary
  • only the last measurement value is returned
• GET /domains/{domain}/sensors/{sensor_id}/measurements/{measurement_id}/value
  • lastN, limit, offset, dateFrom, dateTo are applied to the list of values

[henokzion]

I will test it right away