feat(supabase): add SupabaseBucketDownloader component

[SyedShahmeerAli12]

Related Issues

• partially addresses SupabaseBucketDownloader #3084

Proposed Changes

Adds SupabaseBucketDownloader, a new Haystack component that downloads files from a Supabase Storage bucket and returns them as ByteStream objects for use in indexing pipelines.

Component: haystack_integrations.components.downloaders.supabase.SupabaseBucketDownloader

Key features:

• Downloads files from a Supabase Storage bucket by file path
• Returns ByteStream objects with meta["file_path"] and meta["bucket_name"] set
• Optional file_extensions filter (case-insensitive)
• Failed downloads are logged and skipped — does not raise, returns remaining streams
• MIME type auto-detected from file extension
• Full serialization support (to_dict / from_dict)
• Authenticates via SUPABASE_SERVICE_KEY env var (service role key for private buckets)

Usage:

from haystack_integrations.components.downloaders.supabase import SupabaseBucketDownloader
from haystack.utils import Secret

downloader = SupabaseBucketDownloader(
    supabase_url="https://<project-ref>.supabase.co",
    supabase_key=Secret.from_env_var("SUPABASE_SERVICE_KEY"),
    bucket_name="my-documents",
)
result = downloader.run(sources=["reports/report.pdf", "data/notes.txt"])
streams = result["streams"]

Dependency added: supabase>=2.0.0

How did you test it?

9 unit tests covering:

• Default and custom init parameters
• File extension normalization (case-insensitive)
• Serialization round-trip (to_dict / from_dict)
• run() returns correct ByteStream objects with metadata
• File extension filtering skips non-matching files
• Empty sources returns empty list
• Failed downloads are skipped (logs warning, continues)
• MIME type detection from file extension

Integration test skipped unless SUPABASE_URL and SUPABASE_SERVICE_KEY are set.

Notes for the reviewer

This is the first of the remaining sub-tasks from #2862 (after SupabasePgvectorDocumentStore, SupabasePgvectorEmbeddingRetriever, and SupabasePgvectorKeywordRetriever were merged in #3164).

The supabase>=2.0.0 dependency is added to pyproject.toml. The existing integration only depended on pgvector-haystack.

Checklist

• I have read the contributors guidelines and the code of conduct
• I have updated the related issue with new insights and changes
• I added unit tests and updated the docstrings
• I've used one of the conventional commit types for my PR title: feat:

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Review the following changes in direct dependencies. Learn more about Socket for GitHub.

Diff	Package	Supply Chain Security	Vulnerability	Quality	Maintenance	License
	supabase@​2.29.0

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Coverage report (supabase)

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File	Statements	Missing	Coverage	Coverage (new stmts)	Lines missing
integrations/supabase/src/haystack_integrations/components/downloaders/supabase
supabase_bucket_downloader.py					78-79
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[SyedShahmeerAli12]

@davidsbatista or could anyone please review this PR when you get a chance?

This adds SupabaseBucketDownloader the next sub-task of #2862 after the pgvector components were merged in #3164. Once this is reviewed and merged we can continue with the remaining Supabase features in that issue.

[davidsbatista]

@SyedShahmeerAli12, please, there's no need to tag us and ask to review the PRs, it was open just 2 days ago.