How to fix StorageApiError: Bucket not found in Supabase

// ❌ Wrong - case mismatch
const { data, error } = await supabase
  .storage
  .from('MyBucket')  // Bucket is actually "mybucket"
  .upload('file.png', file);

// ✅ Correct - exact match
const { data, error } = await supabase
  .storage
  .from('mybucket')
  .upload('file.png', file);

if (error) {
  console.error('Error:', error.message);
}

-- In Supabase SQL Editor
create policy "Allow bucket access for all users"
on storage.buckets
for select
using ( true );

create policy "Allow bucket access for authenticated users"
on storage.buckets
for select
to authenticated
using ( true );

create policy "Allow access to specific bucket"
on storage.buckets
for select
using ( name = 'mybucket' );

const { data: existingBucket, error: getError } = await supabase
  .storage
  .getBucket('mybucket');

if (getError && getError.message.includes('not found')) {
  console.log('Bucket not found, creating...');
  
  const { data: newBucket, error: createError } = await supabase
    .storage
    .createBucket('mybucket', {
      public: false,  // Set to true for public access
      fileSizeLimit: 1024 * 1024 * 10  // 10MB limit
    });
  
  if (createError) {
    console.error('Failed to create bucket:', createError.message);
  } else {
    console.log('Bucket created successfully:', newBucket);
  }
} else if (getError) {
  console.error('Error checking bucket:', getError.message);
} else {
  console.log('Bucket already exists:', existingBucket);
}

// ❌ Wrong - service_role with SSR client
import { createServerClient } from '@supabase/ssr';

const supabase = createServerClient(
  process.env.NEXT_PUBLIC_SUPABASE_URL,
  process.env.SUPABASE_SERVICE_ROLE_KEY,  // This won't work as expected
  // ...
);

// ✅ Correct - separate plain client for service_role
import { createClient } from '@supabase/supabase-js';

// For service_role operations (bypasses RLS)
const supabaseAdmin = createClient(
  process.env.NEXT_PUBLIC_SUPABASE_URL!,
  process.env.SUPABASE_SERVICE_ROLE_KEY!,
  {
    auth: {
      autoRefreshToken: false,
      persistSession: false
    }
  }
);

// For user operations (respects RLS)
const supabaseUser = createServerClient(
  process.env.NEXT_PUBLIC_SUPABASE_URL,
  process.env.NEXT_PUBLIC_SUPABASE_ANON_KEY,
  // ...
);

// ❌ Wrong - "public" in path for private bucket
const url = supabase.storage
  .from('mybucket')
  .getPublicUrl('public/file.png');  // Interprets "public" as bucket name

// ✅ Correct - for public buckets
const url = supabase.storage
  .from('mybucket')  // Bucket must be marked as public in dashboard
  .getPublicUrl('file.png');

// ✅ Correct - for private buckets, use signed URLs
const { data, error } = await supabase.storage
  .from('mybucket')
  .createSignedUrl('file.png', 60);  // 60 second expiry

if (error) {
  console.error('Error creating signed URL:', error.message);
} else {
  console.log('Signed URL:', data.signedUrl);
}