.NET Blazor Server — SignalR app on Clever Cloud

A .NET 8 Blazor Server app using SignalR for real-time UI updates, deployed on Clever Cloud's .NET runtime — dressed with the Clever Brand Kit and a "Vu depuis Clever Cloud" panel showing what the platform injects.

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Deploy on Clever Cloud

1. Fork this repository
2. In the Clever Cloud console, create a new .NET application — connect your forked repo
3. No add-on needed
4. Recommended environment variables (see table below): ASPNETCORE_FORWARDEDHEADERS_ENABLED=true, ASPNETCORE_ENVIRONMENT=Production, CC_HEALTH_CHECK_PATH=/health
5. Scaling: keep min = max = 1 instance (Blazor Server circuits live in memory — no horizontal scaling without a SignalR backplane)
6. Push → Clever Cloud builds with dotnet publish and deploys automatically

Project file selection: the official Clever Cloud mechanism is the CC_DOTNET_PROJ environment variable (project name without extension). The repository also ships clevercloud/dotnet.json, kept for compatibility but not documented by Clever Cloud:

clever env set CC_DOTNET_PROJ cc-dotnet-demo   # optional: single .csproj at the root, auto-detected

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Stack

Layer	Technology
Runtime	.NET 8
Framework	Blazor Server
Real-time	SignalR
Design	Clever Brand Kit (Plus Jakarta Sans, navy #13172e, dégradé Clever)

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Features

• Blazor Server with real-time UI updates via SignalR (/counter, InteractiveServer render mode)
• Clever Brand Kit: topbar, hero, certification block, platform panel, footer — one CSS file, no Bootstrap, no JS framework
• "Vu depuis Clever Cloud" panel reading the variables injected by the platform (CC_APP_NAME, APP_ID, INSTANCE_NUMBER, INSTANCE_TYPE, CC_PRETTY_INSTANCE_NAME, CC_COMMIT_ID, CC_DEPLOYMENT_ID) — shows "Local · hors Clever Cloud" when they are absent
• Responsive layout (desktop and mobile)
• GET /health → 200 ok (plain text) for the Clever Cloud health check
• Security headers on every response: X-Content-Type-Options: nosniff, Referrer-Policy: strict-origin-when-cross-origin, X-Frame-Options: DENY (no CSP yet — to be tested in Report-Only mode with SignalR)

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Certification Clever Cloud

The home page puts the Clever Cloud Academy certification right under the hero: two official tracks (Cloud Computing Fundamentals, Advanced Deployment) and a direct call to action. The digital badge is issued automatically once a track is validated.

→ https://academy.clever.cloud/

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Project structure

Program.cs                         → entry point, HTTP pipeline (no HTTPS redirection, no HSTS), security headers, /health
cc-dotnet-demo.csproj              → project file (no NuGet dependency)
Components/App.razor               → <head>: Google Fonts, cc-brand.css, app.css, favicon
Components/Layout/MainLayout.razor → CleverTopbar + @Body + CleverFooter
Components/Layout/CleverTopbar.razor, CleverFooter.razor
Components/Shared/CleverLogo.razor, CleverBadge.razor   → inline SVG (official logo, certification badge)
Components/Shared/CleverCert.razor  → certification block
Components/Shared/PlatformPanel.razor → "Vu depuis Clever Cloud"
Components/Pages/                  → Home, Counter, Error
wwwroot/cc-brand.css               → Clever Brand Kit (copied as-is, do not edit)
wwwroot/app.css                    → demo-specific styles only
clevercloud/dotnet.json            → project file hint (legacy; official mechanism = CC_DOTNET_PROJ)
docs/superpowers/specs/            → design spec of the Clever Brand Kit

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Local Development

Prerequisites

• .NET 8 SDK

Run

git clone https://github.com/Vitiosum/demo-dotnet-blazor
cd demo-dotnet-blazor
dotnet run
# → http://localhost:8080

Locally the topbar shows Local and the platform panel shows Local · hors Clever Cloud: the APP_ID variable only exists on Clever Cloud.

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Environment Variables

Variable	Status	Description
ASPNETCORE_URLS	set by Clever Cloud	http://0.0.0.0:8080 — port 8080 is mandatory on the .NET runtime; overrides the Urls value of appsettings.json
ASPNETCORE_FORWARDEDHEADERS_ENABLED	recommended = true	Enables the ForwardedHeaders middleware on the host: Request.IsHttps and the client IP are read from the X-Forwarded-* headers set by the Clever Cloud proxy
ASPNETCORE_ENVIRONMENT	recommended = Production	Locks the environment (default when absent is already Production)
CC_HEALTH_CHECK_PATH	recommended = /health	Clever Cloud deployment health check on the /health endpoint
CC_DOTNET_PROJ	optional = cc-dotnet-demo	Official project selection mechanism (multi-project repos)
AllowedHosts	optional	Restrict the Host header to the app domains if absolute URLs are ever generated (* by default)

clever env set ASPNETCORE_FORWARDEDHEADERS_ENABLED true
clever env set ASPNETCORE_ENVIRONMENT Production
clever env set CC_HEALTH_CHECK_PATH /health

The app never reads PORT: the listening address comes from ASPNETCORE_URLS (injected) or, locally, from appsettings.json. The platform panel reads the variables Clever Cloud injects on every instance — see the reference.

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Deployment Notes

• UseHttpsRedirection() and UseHsts() are removed — HTTPS and HSTS are handled by the Clever Cloud proxy; the app only receives plain HTTP internally
• appsettings.json binds the app to http://0.0.0.0:8080 (redundant with the injected ASPNETCORE_URLS, kept for local runs)
• CC_DOTNET_PROJ selects the .csproj in multi-project repos (clevercloud/dotnet.json is kept but not documented by Clever Cloud)
• SignalR works out of the box — Clever Cloud supports WebSocket connections
• One instance only: Blazor Server keeps each circuit in memory; scaling to several instances requires a SignalR backplane (Redis) — not part of this demo
• .NET 8 end of support: 10 November 2026 — plan the move to net10.0 (LTS until November 2028, available on Clever Cloud via CC_DOTNET_VERSION)