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basics-csharp

README.md

Terminal basics: C# AppHost and API

Run Slumber, an interactive REST client, inside the Aspire dashboard. Create a note through an ASP.NET Core API, edit it directly in Redis's authenticated REPL, then retrieve the changed value in Slumber.

Slumber displaying a note edited through the Redis REPL

Prerequisites and startup

See the collection's Aspire version requirements.

From this directory:

aspire restore --apphost apphost.cs
aspire start --apphost apphost.cs --isolated
aspire wait --apphost apphost.cs

Open the dashboard URL printed by Aspire. Wait for redis and api to be healthy and slumber to be running. The first start builds the Slumber image. Ports and the container-reachable API address are supplied by Aspire; do not enter a URL into Slumber.

The non-root container packages checksum-verified Slumber 5.3.0 binaries for Linux ARM64/AMD64 and includes Vim. No host Slumber or Vim installation is needed.

What the AppHost adds

apphost.cs declares three resources:

var redis = builder.AddRedis("redis").WithRepl();

var api = builder.AddProject("api", "./api/Notes.Api.csproj")
    .WithReference(redis)
    .WithHttpHealthCheck("/health")
    .WaitFor(redis);

builder.AddDockerfile("slumber", "./slumber")
    .WithEnvironment("BASE_URL", api.GetEndpoint("http"))
    .WaitFor(api)
    .WithTerminal();

WithTerminal() attaches to Slumber's foreground process. Redis's WithRepl() instead adds a resource action that starts a separate, already authenticated redis-cli. The AppHost suppresses the terminal APIs' experimental diagnostic locally.

The API uses Aspire.StackExchange.Redis and sample-local ServiceDefaults for health checks and telemetry. Slumber receives only the API endpoint, not Redis credentials. Its saved requests read that endpoint with {{ env('BASE_URL') }}. HTTP is intentional for this local container-to-API connection; no certificate validation is disabled.

The optional http profile in apphost.run.json also uses unencrypted local dashboard, telemetry, and resource-service connections. This is separate from the API's HTTP traffic and does not disable dashboard authentication. Keep these loopback endpoints private; do not expose or forward this profile to untrusted networks.

Try the round trip

  1. Open Console logs for slumber. Focus the terminal and press r to focus the request list. Use Up/Down to select 01 - Create a note, then Enter to send. Expect 201 Created (or 200 OK if welcome already exists).

  2. Select 02 - List notes or 03 - Read welcome and press Enter. The JSON includes "text": "Hello from Slumber!".

  3. On the Resources page, open redis's Actions menu and select REPL. No password entry is needed. Run:

    HGETALL notes
HSET notes welcome "Edited from Redis"
HGET notes welcome

  4. Hide the terminal panel and return to Slumber. Select 03 - Read welcome and press Enter. Expect 200 OK and "text": "Edited from Redis" without restarting the API.

  5. Send 04 - Update welcome for "text": "Updated from Slumber!", then 05 - Delete welcome for 204 No Content. Reading the deleted note returns 404. 06 - API and Redis health checks readiness.

Tab/Shift+Tab moves between panes, r returns to the request list, and ? shows help. Selecting a request loads it immediately; Enter sends it.

Vim is configured as the default editor. In Vim, press i to edit, then Esc and :wq to save and return to Slumber (:q! discards changes). Collection edits inside the container are disposable; edit slumber/slumber.yml in the repository to retain them across rebuilds.

Data and lifecycle

The API stores plain text in the Redis hash notes, with note IDs as fields. IDs accept 1-40 lowercase ASCII letters, digits, or hyphens. A JSON text value must contain 1-1000 UTF-16 characters and cannot be whitespace-only. PUT creates (201) or replaces (200); missing reads/deletes return 404, invalid input returns 400, and Redis failures return 503. Request bodies are limited to 10 KiB.

There is no persistent volume or API-local cache. To reset only this demo's data, run DEL notes in the REPL, then resend the create request. Do not use FLUSHALL.

Type quit in redis-cli before closing its tab. Hiding a terminal panel is not a process stop. Slumber exits with q (or Ctrl+C); use its resource Start or Restart action to launch it again. Reloading the dashboard reconnects to a still-running Slumber process. Use Fit or the terminal size selector to adjust its layout.

Stop this sample explicitly:

aspire stop --apphost apphost.cs

Checks and troubleshooting

dotnet test tests/Notes.Tests.csproj

The focused tests cover the API contract with an in-memory store; the walkthrough exercises real Redis and the interactive terminals. TerminalNotes.slnx includes the API, ServiceDefaults, and tests in the repository build.

If REPL is missing, check aspire --version and restart with the matching CLI. If Slumber is waiting, inspect api and redis health first. If requests cannot connect, verify that BASE_URL is populated by the AppHost; do not replace it with localhost (which means the Slumber container itself). Changes to the Dockerfile or saved collection require rebuilding/restarting the sample.

Keep the dashboard private to trusted users: its Redis REPL grants authenticated datastore access. The unauthenticated HTTP notes API allows anyone who can reach it to read, replace, and delete every demo note. Use only disposable, non-sensitive data; this is a local demonstration, not production.