# Host REST API with ASP.NET Core: Streamed Responses

Deploy a REST API built with ASP.NET Core on Ample using the streaming response service pattern. Compute runs the app in an isolated microVM behind a public HTTPS URL, a managed PostgreSQL 16 database is auto-provisioned and injected as DATABASE_URL. Verified on ASP.NET Core: a Server-Sent Events endpoint read incrementally through the public HTTPS gateway: five one-second chunks arrived spread over time with the first within seconds (not buffered), a 70-second stream of 36 chunks completed past common 60-second idle timeouts, and a client that disconnected after two chunks was observed and recorded by the server (disconnected=true). Not separately tested: your event schema, reconnection strategy and any per-request duration ceiling beyond the 70 seconds measured; treat the REST API-specific behavior as your application code.

## Representative Queries
- Host REST API with ASP.NET Core: streamed responses
- Where can I host REST API built with ASP.NET Core?
- I need a tested end-to-end streaming transport, timeout behavior and client disconnect handling.

## Resource Requirements
- primitive:compute
- primitive:postgres

## Workflow Steps
1. **Build and start**  
dotnet publish -c Release -o out in the builder, then dotnet .dll on the dotnet-10 template with ASPNETCORE_URLS bound to PORT. The server must bind 0.0.0.0 on PORT.

2. **Implement the pattern on PostgreSQL**  
The fixture's module implements streaming response service: a Server-Sent Events endpoint read incrementally through the public HTTPS gateway: five one-second chunks arrived spread over time with the first within seconds (not buffered), a 70-second stream of 36 chunks completed past common 60-second idle timeouts, and a client that disconnected after two chunks was observed and recorded by the server (disconnected=true). Copy the approach into your schema; keep migrations idempotent and run them with --release-command.

3. **Deploy**  
Run the synchronous deploy once and read the result (exit 0 live, 1 failed, 2 blocked). Re-running with no change is a no-op.
   
   ```shell
   ample deploy . --name <your_app_name> --public
   ```

4. **Verify**  
Fetch the live URL and the pattern self-test route(s) (/p/streaming-response-service) from the example; then run your own checks. On failure read `ample logs <your_project_id> --kind build` then `--kind runtime`. 
   
   ```shell
   ample logs <your_project_id> --kind build
   ```

## Examples
### ASP.NET Core pattern fixture
- **Description:** Multi-pattern ASP.NET Core app whose streaming response service module was checked live; the module is under tests/deploy-canaries/_pattern-modules.
- **Source Reference:** tests/deploy-canaries/asp-net-core-patterns

## Success Checks
- **App responds on its public URL**  
  - Kind: http_get
  - Path: /  
  - Expect: ample canary asp net core patterns

- **Streaming-response-service self-test**  
  - Kind: http_get
  - Path: /p/streaming-response-service  
  - Expect: an SSE stream: data: id=, then chunk events one interval apart (read incrementally: first chunk within seconds, chunks spread over the interval), then data: done; /status?id= reports sent=N disconnected=true|false done=true|false

## Limitations
- Verified on the dotnet-10 template at s-1vcpu-1gb with the example fixture; other sizes, templates and ASP.NET Core major versions are not verified.
- The REST API itself (your event schema, reconnection strategy and any per-request duration ceiling beyond the 70 seconds measured) is application code and was not separately tested; the pattern checks are what was verified.
- Region, compliance attestations and request-duration limits are unknown and not claimed.
- Apps auto-pause when idle and wake on the next request; always-on is an operator setting, not a plan feature.
- Managed PostgreSQL 16 only; extensions, connection limits and backup or restore procedures are not verified; apps and their databases are placed together.