Kebechet.Build.RemoteAssets 1.0.0

Build.RemoteAssets

Downloads files over HTTP during the build and registers them as build items, so large or frequently replaced binaries stay out of the repository.

Installation

dotnet add package Kebechet.Build.RemoteAssets

Usage

<ItemGroup>
  <RemoteAsset Include="https://cdn.example.com/v1/hero.webp" Path="wwwroot/img" />
  <RemoteAsset Include="https://cdn.example.com/v1/intro.mp4" Path="wwwroot/video" />
</ItemGroup>

In a Razor SDK project those resolve at _content/<YourProject>/img/hero.webp, exactly as if they had been committed under wwwroot/. In a console or class library project they land next to the built assembly.

Item metadata

Properties

Set RemoteAssetPath once when everything shares a folder:

<PropertyGroup>
  <RemoteAssetPath>wwwroot/img/app-previews</RemoteAssetPath>
</PropertyGroup>

<ItemGroup>
  <RemoteAsset Include="https://cdn.example.com/v1/training-plans.webp" />
  <RemoteAsset Include="https://cdn.example.com/v1/workout-summary.webp" />
</ItemGroup>

There is no version property - the URL is the cache key

A file already on disk for the current URL is never requested again, so incremental and offline builds do no network work. Change the URL and the cached copy is replaced:

<RemoteAsset Include="https://cdn.example.com/v2/hero.webp" Path="wwwroot/img" />

Verifying content with Sha256

A URL is mutable. If someone re-uploads over v1/hero.webp you would silently ship different bytes and no commit would record it. Sha256 turns that into a build failure naming the file:

<RemoteAsset Include="https://cdn.example.com/v1/hero.webp"
             Path="wwwroot/img"
             Sha256="9f2c4e8a1b7d5f30c6e94a2b8d1f7c3e5a09b4d6f28e1c7a3b5d9f04e6a2c8b1" />

Compute one with Get-FileHash hero.webp -Algorithm SHA256 or sha256sum hero.webp.

URLs with a query string (SAS tokens)

? is an MSBuild wildcard. A URL containing one, placed in Include, is expanded as a file glob, matches nothing, and the item disappears without an error. Pass such URLs as Url metadata instead, with the file name in Include:

<RemoteAsset Include="hero.webp"
             Url="https://account.blob.core.windows.net/assets/hero.webp?sv=2024-01-01&amp;sig=..."
             Path="wwwroot/img" />

The package detects the broken form and fails with a message pointing here rather than letting it pass silently.

Retired assets are cleaned up

Every downloaded file is tracked by a stamp under obj/RemoteAssets/. Remove an item and the next build deletes the file it left behind. Only files this package downloaded are ever deleted, so a committed file sitting in the same folder as fetched ones is never touched.

Multi-targeted projects

For a project building several target frameworks, the fetch runs once in the outer build before the inner builds fan out. Without that, every inner build would race the others to download the same URL into the same destination file - they run in parallel, so an existence check is not enough on its own.

Ignore the fetched files in git

The point of the package is that these files are not committed:

wwwroot/img/hero.webp
wwwroot/video/intro.mp4

Building without network access

A build whose files are already cached needs no network. A cold build with no cache fails with a message naming the URL, rather than producing output with the asset silently missing. Set RemoteAssetsEnabled=false to skip fetching altogether.

License

MIT