Use Retrieval API

This guide explains how to retrieve data that has been stored in the Digital Data Backbone using the Retrieval API. The API provides a unified interface for querying data across all connected database nodes.

Prerequisites

  • A running DDB system with at least one database node storing data (see Connect a Database Node)

  • The Retrieval Web Service (RWS) running and accessible

How the Retrieval API Works

        flowchart LR
    subgraph API[Retrieval API]
      MDS["Metadata Store"] --> RWS["Retrieval Web Service"]
    end
    RWS --> User[Your Application]
    DBN[Database Nodes] --> RWS
    Broker --> MDS

    classDef highlight fill:#094d57,stroke:#0a3d4d,color:white
    class RWS highlight

The Retrieval API consists of two components:

  • Metadata Store (MDS) — PostgreSQL database tracking data location, format, and descriptive metadata

  • Retrieval Web Service (RWS) — REST API that queries the MDS to find data and retrieves it from the appropriate database nodes

API Endpoints

Endpoint

Method

Description

/mfi-ddb/type0

GET

Get information about available endpoints.

/mfi-ddb/type1

POST

Search trials using metadata store filters. Returns matching trial UUIDs.

/mfi-ddb/type2

POST

Retrieve data for a specific trial UUID.

/mfi-ddb/type3

POST

Search trials and retrieve data when a unique trial is found. If multiple trials match, returns list of UUIDs instead.

Next Steps