# Host event registration with ASP.NET Core: file attachments

Deploy a event registration built with ASP.NET Core on Ample using the browser file uploads 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, a private S3-compatible bucket holds objects with credentials delivered as encrypted environment variables. Verified on ASP.NET Core: content-type and size validation that rejects disallowed files, an object written to a private bucket and a row linking the record to the object key (reject=ok upload=ok linked=ok). Not separately tested: your upload UI, allowed types, size limits and virus scanning; treat the event registration-specific behavior as your application code.

## Representative Queries
- Host event registration with ASP.NET Core: file attachments
- Where can I host Event registration built with ASP.NET Core?
- I need a restricted upload flow, file validation and record-to-object linkage.

## Resource Requirements
- primitive:compute
- primitive:postgres
- primitive:s3-compatible-object-storage

## Infrastructure Requirements
- **Compute**: Apps run in isolated x86_64 Firecracker microVMs that auto-pause when idle and wake on request; sizes are the priced VM sizes.
- **PostgreSQL**: Managed PostgreSQL 16 runs in its own microVM and is auto-provisioned when an app needs a database and no DATABASE_URL is supplied.
- **S3-compatible object storage**: Buckets are S3-compatible with issued credentials; PutObject and GetObject are verified by canary. Other S3 operations are not verified.

## Framework
- ASP.NET Core

## Workload
- Event registration

## Execution Status
- Ready

## Prerequisites
- A ASP.NET Core project that builds and starts with the documented commands (dotnet publish -c Release -o out in the builder, then dotnet .dll on the dotnet-10 template with ASPNETCORE_URLS bound to PORT)
- A PostgreSQL driver reading DATABASE_URL at runtime (auto-provisioned when omitted, or supplied with --env)
- A bucket from `ample bucket create` with its credentials passed as encrypted S3_* environment variables
- An Ample account token with servers:write, databases:read, buckets:read

## Tested Configuration
- **Template**: dotnet-10
- **Runtime**: dotnet
- **Size**: s-1vcpu-1gb
- **Build**: dotnet publish -c Release -o out
- **Start**: ASPNETCORE_URLS=http://0.0.0.0:$PORT dotnet out/$(basename $(ls out/*.runtimeconfig.json | head -n 1) .runtimeconfig.json).dll

## 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 browser file uploads: content-type and size validation that rejects disallowed files, an object written to a private bucket and a row linking the record to the object key (reject=ok upload=ok linked=ok). Copy the approach into your schema; keep migrations idempotent and run them with --release-command.
3. **Wire object storage**: Create the bucket(s), then pass endpoint, region, bucket and keys as --env values. Use path-style addressing. Keep private data in an unpublished bucket.
4. **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.
   Command: `ample deploy . --name  --public --env S3_ENDPOINT=... --env S3_REGION=... --env S3_BUCKET=... --env S3_ACCESS_KEY_ID=... --env S3_SECRET_ACCESS_KEY=...`
5. **Verify**: Fetch the live URL and the pattern self-test route(s) (`/p/browser-file-uploads`) from the example; then run your own checks. On failure read `ample logs  --kind build` then `--kind runtime`.
   Command: `ample logs  --kind build`

## Examples
- **ASP.NET Core pattern fixture**: Multi-pattern ASP.NET Core app whose browser file uploads module was checked live; the module is under tests/deploy-canaries/_pattern-modules.

## Success Checks
- app responds on its public URL
- browser-file-uploads self-test

## 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 event registration itself (your upload UI, allowed types, size limits and virus scanning) 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.

## Cost Estimate
- **Currency**: USD
- **Monthly Amount**: 10.0
- **Basis**: size prices from pricing.toml.
- **Components**:
  - app server: s-1vcpu-1gb (monthly: 5.0)
  - managed PostgreSQL database: s-1vcpu-1gb (monthly: 5.0)

## Evidence Summary
- **Canary Run**: ASP.NET Core pattern fixture deployed on Ample; checks passed for browser-file-uploads and configuration-secrets.

## Last Verified At
- 2026-09-21T01:15:54Z

## Unknowns
- Region availability is unknown until a verified region fact is recorded.
- Compliance attestations are unknown; none are claimed.

## Formats
- **html**: [Link](/content/recipes/event-registration/asp-net-core/attachments/index.html)
- **markdown**: [Link](/content/recipes/event-registration/asp-net-core/attachments.md)
- **json**: [Link](https://api.ample.computer/v1/catalog/recipes/page%3Arecipes%3Aevent-registration%3Aasp-net-core%3Aattachments)

## Next Actions
1. **Browse the catalog index** - GET /v1/catalog
2. **Search published recipes by intent, stack and constraints** - POST /v1/catalog/search
3. **Prepare a side-effect-free deployment plan for an authorized project** - POST /v1/catalog/plan
4. **Read the existing agent authentication setup** - GET /mcp/setup
5. **Browse Event registration** - GET /v1/catalog/nodes/workload%3Aevent-registration
6. **Browse ASP.NET Core** - GET /v1/catalog/nodes/stack%3Aframework-asp-net-core
7. **Browse Browser file uploads** - GET /v1/catalog/nodes/pattern%3Abrowser-file-uploads
8. **Browse Deploy web app** - GET /v1/catalog/nodes/intent%3Adeploy-web-app