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- require 'securerandom'
- module Agents
- class UserLocationAgent < Agent
- cannot_be_scheduled!
- gem_dependency_check { defined?(Haversine) }
- description do
- <<-MD
- #{'## Include `haversine` in your Gemfile to use this Agent!' if dependencies_missing?}
- The UserLocationAgent creates events based on WebHook POSTS that contain a `latitude` and `longitude`. You can use the [POSTLocation](https://github.com/cantino/post_location) or [PostGPS](https://github.com/chriseidhof/PostGPS) iOS app to post your location.
- Your POST path will be `https://#{ENV['DOMAIN']}/users/#{user.id}/update_location/:secret` where `:secret` is specified in your options.
- If you want to only keep more precise locations, set `max_accuracy` to the upper bound, in meters. The default name for this field is `accuracy`, but you can change this by setting a value for `accuracy_field`.
- If you want to require a certain distance traveled, set `min_distance` to the minimum distance, in meters. Note that GPS readings and the measurement itself aren't exact, so don't rely on this for precision filtering.
- MD
- end
- event_description <<-MD
- Assuming you're using the iOS application, events look like this:
- {
- "latitude": "37.12345",
- "longitude": "-122.12345",
- "timestamp": "123456789.0",
- "altitude": "22.0",
- "horizontal_accuracy": "5.0",
- "vertical_accuracy": "3.0",
- "speed": "0.52595",
- "course": "72.0703",
- "device_token": "..."
- }
- MD
- def working?
- event_created_within?(2) && !recent_error_logs?
- end
- def default_options
- {
- 'secret' => SecureRandom.hex(7),
- 'max_accuracy' => '',
- 'min_distance' => '',
- }
- end
- def validate_options
- errors.add(:base, "secret is required and must be longer than 4 characters") unless options['secret'].present? && options['secret'].length > 4
- end
- def receive(incoming_events)
- incoming_events.each do |event|
- interpolate_with(event) do
- handle_payload event.payload
- end
- end
- end
- def receive_web_request(params, method, format)
- params = params.symbolize_keys
- if method != 'post'
- return ['Not Found', 404]
- end
- if interpolated['secret'] != params[:secret]
- return ['Not Authorized', 401]
- end
- handle_payload params.except(:secret)
- return ['ok', 200]
- end
- private
- def handle_payload(payload)
- location = Location.new(payload)
- accuracy_field = interpolated[:accuracy_field].presence || "accuracy"
- def accurate_enough?(payload, accuracy_field)
- !interpolated[:max_accuracy].present? || !payload[accuracy_field] || payload[accuracy_field].to_i < interpolated[:max_accuracy].to_i
- end
- def far_enough?(payload)
- if memory['last_location'].present?
- travel = Haversine.distance(memory['last_location']['latitude'].to_i, memory['last_location']['longitude'].to_i, payload['latitude'].to_i, payload['longitude'].to_i).to_meters
- !interpolated[:min_distance].present? || travel > interpolated[:min_distance].to_i
- else
- true
- end
- end
- if location.present? && accurate_enough?(payload, accuracy_field) && far_enough?(payload)
- if interpolated[:max_accuracy].present? && !payload[accuracy_field].present?
- log "Accuracy field missing; all locations will be kept"
- end
- create_event payload: payload, location: location
- memory["last_location"] = payload
- end
- end
- end
- end
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