feat(storage_client): use dedicated storage host for storage lib (allows >50GB uploads) (#1285)

* feat(storage_client): use dedicated storage host for storage lib (allows >50GB uploads)

Transform legacy storage URLs to use the dedicated storage host which
disables request buffering and allows uploads up to 500GB.

Changes:
- Added _transformStorageUrl() method to transform legacy URLs
- Legacy format: project-ref.supabase.co/storage/v1
- New format: project-ref.storage.supabase.co/v1
- Only transforms Supabase platform hosts (supabase.co, supabase.in, supabase.red)
- Preserves non-platform hosts and localhost URLs unchanged
- Added comprehensive tests for URL transformation scenarios

This matches the implementation in storage-js PR #230 and enables
large file uploads (>50GB) by using the dedicated storage infrastructure.

Closes SDK-230

* style: dart fmt

Author: grdsdev

packages/storage_client/lib/src/storage_client.dart

@@ -42,7 +42,7 @@ class SupabaseStorageClient extends StorageBucketApi {
         ),
         _defaultRetryAttempts = retryAttempts,
         super(
-          url,
+          _transformStorageUrl(url),
           {...Constants.defaultHeaders, ...headers},
           httpClient: httpClient,
         ) {
@@ -51,6 +51,39 @@ class SupabaseStorageClient extends StorageBucketApi {
     _log.finest('Initialize with headers: $headers');
   }
 
+  /// Transforms legacy storage URLs to use the dedicated storage host.
+  ///
+  /// If legacy URI is used, replace with new storage host (disables request buffering to allow > 50GB uploads).
+  /// "project-ref.supabase.co/storage/v1" becomes "project-ref.storage.supabase.co/v1"
+  static String _transformStorageUrl(String url) {
+    final uri = Uri.parse(url);
+    final hostname = uri.host;
+
+    // Check if it's a Supabase host (supabase.co, supabase.in, or supabase.red)
+    final isSupabaseHost = RegExp(r'supabase\.(co|in|red)$').hasMatch(hostname);
+
+    // If it's a legacy storage URL, transform it
+    const legacyStoragePrefix = '/storage';
+    if (isSupabaseHost &&
+        !hostname.contains('storage.supabase.') &&
+        uri.path.startsWith(legacyStoragePrefix)) {
+      // Remove /storage from pathname
+      final newPath = uri.path.substring(legacyStoragePrefix.length);
+      // Replace supabase. with storage.supabase. in hostname
+      final newHostname = hostname.replaceAll('supabase.', 'storage.supabase.');
+
+      // Reconstruct the URI
+      return uri
+          .replace(
+            host: newHostname,
+            path: newPath,
+          )
+          .toString();
+    }
+
+    return url;
+  }
+
   /// Perform file operation in a bucket.
   ///
   /// [id] The bucket id to operate on.

packages/storage_client/test/basic_test.dart

@@ -287,4 +287,60 @@ void main() {
       expect(client.headers['X-Client-Info'], 'supabase-dart/0.0.0');
     });
   });
+
+  group('URL Construction', () {
+    test('should update legacy prod host to new host', () {
+      const inputUrl = 'https://blah.supabase.co/storage/v1';
+      const expectedUrl = 'https://blah.storage.supabase.co/v1';
+      client = SupabaseStorageClient(inputUrl, {
+        'Authorization': 'Bearer $supabaseKey',
+      });
+      expect(client.url, expectedUrl);
+    });
+
+    test('should update legacy staging host to new host', () {
+      const inputUrl = 'https://blah.supabase.red/storage/v1';
+      const expectedUrl = 'https://blah.storage.supabase.red/v1';
+      client = SupabaseStorageClient(inputUrl, {
+        'Authorization': 'Bearer $supabaseKey',
+      });
+      expect(client.url, expectedUrl);
+    });
+
+    test('should accept new host without modification', () {
+      const inputUrl = 'https://blah.storage.supabase.co/v1';
+      const expectedUrl = 'https://blah.storage.supabase.co/v1';
+      client = SupabaseStorageClient(inputUrl, {
+        'Authorization': 'Bearer $supabaseKey',
+      });
+      expect(client.url, expectedUrl);
+    });
+
+    test('should not modify non-platform hosts', () {
+      const inputUrl = 'https://blah.supabase.co.example.com/storage/v1';
+      const expectedUrl = 'https://blah.supabase.co.example.com/storage/v1';
+      client = SupabaseStorageClient(inputUrl, {
+        'Authorization': 'Bearer $supabaseKey',
+      });
+      expect(client.url, expectedUrl);
+    });
+
+    test('should support local host with port without modification', () {
+      const inputUrl = 'http://localhost:1234/storage/v1';
+      const expectedUrl = 'http://localhost:1234/storage/v1';
+      client = SupabaseStorageClient(inputUrl, {
+        'Authorization': 'Bearer $supabaseKey',
+      });
+      expect(client.url, expectedUrl);
+    });
+
+    test('should update legacy supabase.in host to new host', () {
+      const inputUrl = 'https://blah.supabase.in/storage/v1';
+      const expectedUrl = 'https://blah.storage.supabase.in/v1';
+      client = SupabaseStorageClient(inputUrl, {
+        'Authorization': 'Bearer $supabaseKey',
+      });
+      expect(client.url, expectedUrl);
+    });
+  });
 }