Storage

Supabase.Storage

A C# client for Supabase Storage — upload, download, and serve files from buckets, with signed and public URLs.

Part of the Supabase C# SDK. Most projects use it through the Supabase meta-package (supabase.Storage); reference this package directly when you only need storage.

Installation

dotnet add package Supabase.Storage

Targets .NET Standard 2.0.

Getting started

Create a client pointed at your project's Storage URL, passing your key as a header:

using Supabase.Storage;

var client = new Client("https://PROJECT_ID.supabase.co/storage/v1", new Dictionary<string, string>
{
    { "apikey", SUPABASE_KEY },
    { "Authorization", $"Bearer {SUPABASE_KEY}" }
});

Buckets

await client.CreateBucket("avatars");

var bucket = await client.GetBucket("avatars");
var all = await client.ListBuckets();

await client.EmptyBucket("avatars");
await client.DeleteBucket("avatars");

Files

Work with a bucket's files through From:

var bucket = client.From("avatars");

// Upload from a local path or from bytes.
await bucket.Upload("./local.png", "me.png");
await bucket.Upload(bytes, "me.png");

// List, move, copy, remove.
var files = await bucket.List();
await bucket.Move("me.png", "old/me.png");
await bucket.Copy("old/me.png", "backup/me.png");
await bucket.Remove("old/me.png");

// Download to a local path (returns the path) or into memory (returns bytes).
await bucket.Download("me.png", "./downloaded.png");
byte[] data = await bucket.Download("me.png");

URLs

// Public bucket: build a URL directly (pass null for no image transform).
var publicUrl = bucket.GetPublicUrl("me.png", null);

// Private bucket: sign a URL that expires (seconds).
var signedUrl = await bucket.CreateSignedUrl("me.png", 3600);

Error handling

Storage failures throw a SupabaseStorageException. Use Code for the exact service error (for example, NoSuchKey) and Reason for the broader classification. Code is null when the response does not include one. See the Storage error code reference.

Observability (OpenTelemetry)

The client emits traces and metrics through System.Diagnostics, so you can wire them into OpenTelemetry (or any ActivityListener / MeterListener) without taking a dependency on the OpenTelemetry packages. Emission is zero-cost while nothing is listening, so it is always on and stays silent until you subscribe.

Register the client's ActivitySource and Meter by name. Use the StorageDiagnostics.SourceName constant rather than hardcoding the string, so a typo becomes a compile error instead of a silent no-op:

using OpenTelemetry.Metrics;
using OpenTelemetry.Trace;
using Supabase.Storage;

// Requires OpenTelemetry.Extensions.Hosting and an exporter package (e.g. OTLP) in your app.
builder.Services.AddOpenTelemetry()
    .WithTracing(tracing => tracing
        .AddSource(StorageDiagnostics.SourceName)
        .AddOtlpExporter())
    .WithMetrics(metrics => metrics
        .AddMeter(StorageDiagnostics.SourceName)
        .AddOtlpExporter());

Once subscribed you get:

• A client span per request, named {METHOD} {path} and following OpenTelemetry HTTP conventions (method, status code, and a sanitized URL). The query string is never recorded — Storage signed URLs carry a token there. Upload and download spans additionally carry a storage.transfer.direction tag (upload / download). The resumable (TUS) upload is reported as a single operation span covering the whole transfer, rather than one span per underlying chunk request.
• supabase.storage.http.request.duration (seconds) for control-plane requests.
• supabase.storage.transfer.duration (seconds) and supabase.storage.transfer.size (bytes) for uploads and downloads, tagged by direction — because a duration alone does not describe a file transfer.

If you are not using the OpenTelemetry SDK, a raw listener works too:

using System.Diagnostics;
using Supabase.Storage;

using var listener = new ActivityListener
{
    ShouldListenTo = source => source.Name == StorageDiagnostics.SourceName,
    Sample = (ref ActivityCreationOptions<ActivityContext> _) => ActivitySamplingResult.AllData,
    ActivityStopped = activity => Console.WriteLine($"{activity.OperationName} {activity.Duration.TotalMilliseconds}ms {activity.Status}")
};
ActivitySource.AddActivityListener(listener);

Contributing

Contributions are welcome. See the repository root for how to build and test the SDK.

License

MIT