Retrieve Metrics from API

[philipbaileynar]

Implement the ability to retrieve/download metrics from the cm.org API and store them in the Workbench database. Users can then use the new revised metric view #17 to visualize the metrics.

Outstanding Questions:

• Will downloading metrics replace existing metrics stored in the workbench? Or will users have the ability to store multiple versions?
• How will users pick which metric schema(s) to download?
• How will users pick which visits or watersheds to download?
• How will the Workbench distinguish between downloaded metrics and those scraped or run locally? Currently the Workbench is focused on locally run metrics and creates a single record in Metric_Results that represents the XML file from which metrics are scraped. This allows for multiple versions of each metric to be stored for a visit. There's no concept of official versions of metrics, or the ones pulled from cm.org.

[philipbaileynar]

Here's a first draft of the metric retrieval UI. I really don't like users having to enter a batch name. I also don't like the checkbox for deleting existing data. I think that we should remove both these controls for regular users. You can only have one copy of each metric schema. It always deletes any existing data before downloading new data.

In the background the Workbench will maintain the concept of a batch. But regular users won't see or need to manage this. They will have one and only copy of the latest data for each metric schema that they choose to download. Advanced users can scrape batches of metrics alongside these downloaded metric values for validation purposes.

[philipbaileynar]

This is done and working!

https://www.youtube.com/watch?v=pr8i_1GIaXU&feature=youtu.be