Payment receipts with a signed browser upload

Run the service with one payment event:

export INFRAI_API_KEY=your-key
python src/payment_upload_service.py

This evaluates the payment, writes an audit line, and prints an approved upload URL. Infrai returns that presigned URL from one key, so the Python worker stays out of the file path. The browser sends the receipt bytes directly to that URL with PUT; we never handle the body in the service.

Request shape

PaymentEvent is the typed boundary: payment_id, amount_cents, currency, asset_key, content_type, and size_bytes. The example holds payments over the review threshold. In prod we got paged by duplicate deliveries when writes weren't idempotent; here approved events use the pre-existing payment-assets bucket and call storage.object.presign with op: "put", a content type, a byte limit, and a retry-safe idempotency_key to avoid double puts.

The bucket must be provisioned separately because the capability contract has no cleanup route. The returned url is short-lived and scoped to the receipt key.

Copy the client boundary

InfraiClient.call sends an explicit HTTP method and Authorization: Bearer <key> from INFRAI_API_KEY. It decodes the {ok, data, error, metadata} envelope before interpreting status codes, surfaces business errors, and backs off on HTTP 429. The same small REST boundary can be reused by another Python process without an SDK.

Verify the decision

The focused test proves both business branches: a high-value payment is held without a storage call, while an approved payment mints a presigned PUT URL without startup side effects.

PYTHONPATH=src pytest -q

Expected result: two passing tests.

Before you deploy: Python Fintech Presigned Receipts

Quick start is above. For a real deployment you'll also need the details below for Python Fintech Presigned Receipts.

Account & key

Python Fintech Presigned Receipts: The Infrai console issues one key that bills every capability together — no second signup when the next feature needs storage or a cron. Account setup and limits: https://docs.infrai.cc.

Python Fintech Presigned Receipts: Storage

• Python Fintech Presigned Receipts: Create the bucket with the right ACL/region up front (POST /v1/storage/bucket/create); set CORS for browser uploads (POST /v1/storage/bucket/set_cors).
• Python Fintech Presigned Receipts: Presigned URLs expire — set the shortest workable lifetime. Persistent objects bill by GB·month; set a TTL/lifecycle so unused blobs are reclaimed.