Choosing a Provider

Every Domain Services module separates the service (business logic) from the repository (data access). You pick the repository that matches where your data lives. The service code doesn't change.

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Decision guide

Question	Answer	Provider to use
Is this a demo, prototype, or local dev?	Yes	JSON file (JsonRepository) — zero infra, data is a plain .json file
Does your data already live in PostgreSQL?	Yes	PostgreSQL (DHI.Services.Provider.PostgreSQL)
Are you proxying an existing DS Web API?	Yes	DS (DHI.Services.Provider.DS)
Do you need DFS0/DFS2/DFSU file access?	Yes	MIKECore (DHI.Services.Provider.MIKECore)
Do you need MCLite / MIKE Cloud Lite storage?	Yes	MCLite (DHI.Services.Provider.MCLite)
Do you need live USGS water data (US only)?	Yes	USGS (DHI.Services.Provider.USGS)
Are you reading from MIKE Cloud?	Yes	MIKE Cloud (DHI.Services.Provider.MIKECloud)

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Provider details

JSON (file-based)

Built into the core DHI.Services package — no extra install needed.

var repo = new JsonRepository<MySensor, Guid>("[AppData]sensors.json".Resolve());

Use when: local development, demos, small datasets that don't need a database.

Limitations: no concurrent writes, not suitable for production under load.

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PostgreSQL

dotnet add package DHI.Services.Provider.PostgreSQL

The connection string goes in connections.json or an environment variable:

"ConnectionString": "[env:POSTGRES_CONN]"

Where POSTGRES_CONN = "Server=host;Port=5432;Database=db;User Id=user;Password=pass".

Use when: production deployments, shared data, concurrent access, durable storage.

Most domain modules (Scalars, TimeSeries, Jobs, GIS, etc.) have a PostgreSQL repository. Check the module's reference page to confirm support.

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DS (Domain Services remote proxy)

dotnet add package DHI.Services.Provider.DS

Proxies calls to another DS Web API. The connection string is the base URL of the remote API.

Use when: you want to aggregate data from another DS deployment without ETL, or fan out to multiple instances.

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MIKECore (DFS files)

dotnet add package DHI.Services.Provider.MIKECore

Reads DFS0, DFS2, DFSU, and mesh files. Requires the MIKE SDK assemblies to be present.

Use when: your data is in DHI's binary model file formats.

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MCLite

dotnet add package DHI.Services.Provider.MCLite

Use when: you're working within the MIKE Cloud Lite platform.

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USGS

dotnet add package DHI.Services.Provider.USGS

Reads time series from the USGS Water Services API (US gauge stations).

Use when: you need live or historical water data from USGS without maintaining your own ETL pipeline.

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Running multiple providers side-by-side

A single Web API can serve multiple providers simultaneously — each with its own connectionId. For example, one API can expose JSON data under sensors-local and PostgreSQL data under sensors-prod:

{
  "$type": "System.Collections.Generic.Dictionary`2[[System.String, mscorlib],[DHI.Services.IConnection, DHI.Services]], mscorlib",
  "sensors-local": {
    "$type": "MyApp.SensorServiceConnection, MyApp",
    "RepositoryType": "MyApp.SensorRepository, MyApp",
    "ConnectionString": "[AppData]sensors.json",
    "Id": "sensors-local"
  },
  "sensors-prod": {
    "$type": "MyApp.SensorServiceConnection, MyApp",
    "RepositoryType": "DHI.Services.Provider.PostgreSQL.SensorRepository, DHI.Services.Provider.PostgreSQL",
    "ConnectionString": "[env:POSTGRES_CONN]",
    "Id": "sensors-prod"
  }
}

See Register Services Dynamically with connections.json for full setup.