New row violates row-level security policy .NET API on Supasbase file upload

Question

I get this error while uploading files on Supabase storage, again Supabase storage not table :

new row violates row-level security policy

This is the code I am using in .NET:

internal sealed class StorageRepository : IStorageRepository
{
    private readonly Client _client;

    public StorageRepository(Client client)
    {
        _client = client;
    }

    
    public async Task<string> SaveFileAsync(
       byte[] file,
       string identifier,
       string bucketName)
    {

        var result = await _client
                .Storage
                .From(bucketName)
                .Upload(
                     data: file,
                     supabasePath: identifier);

        return result;
    }
}

This is complete error with detailed exception :

new row violates row-level security policy at Supabase.Storage.Extensions.HttpClientProgress.UploadAsync(HttpClient client, Uri uri, Stream stream, Dictionary`2 headers, Progress`1 progress) at Supabase.Storage.StorageFileApi.UploadOrUpdate(Byte[] data

I have tried by adding a new policy which allows only authenticated user to { SELECT, UPDATE, DELETE, UPDATE } but still it did not work:

Answer 1

A question regarding new row violates row-level security policy was asked by lucasmrl on Supabase's GitHub in 2021. lucasmrl answered their own question with some insight and a suggestion for how to handle the situation. Maybe that post can be useful?

---

To sum it up:

Scenario

1. The user creates an account and a public bucket containing a folder
2. The user tries to upload an image with the following code:

const { data, error } = await supabase.storage
    .from("bucket ID")
    .upload("file name", file, { cacheControl: "3600" });

3. The user receives an error message referencing a table and a security policy, both of which the user does not expect to exist:

"new row violates row-level security policy for table "objects"" statusCode: "42501"

Insight

Even if the bucket is "public", you still need to set up policies

Policy suggestion

To let people VIEW files in a bucket and UPLOAD files to a bucket, execute the following SQL queries:

VIEW: create select policy

create policy "Public Access Bucket Images Get"
on storage.objects for select
using ( bucket_id = 'bucket ID' );

UPLOAD: create insert policy

create policy "Public Access Bucket Images Post"
on storage.objects for insert
with check ( bucket_id = 'bucket ID' );

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More on creating policies in Supabase in the docs.