Direct browser upload: Behavior and interfaces
Defines actors, operations, states, interfaces, errors, limits, and authorization for direct browser upload. This reference fixes the adoption boundary, failure behavior, and observable evidence while leaving environment-specific limits configurable.
Package status: reference context ready for human review. The contract and test scenarios are complete, but no claim is made that an adopting implementation has passed them.
Decision
For Direct browser upload, adopt an ownership record separate from the opaque object key. Expose a resource or event contract with stable identity, authorization, validation, idempotency, compatibility, and explicit errors. This package is a reference contract: the adopting team must choose numeric limits, providers, jurisdictions, and operational owners from evidence in its own environment.
Scope
- The Direct browser upload actors, inputs, outputs, states, policy or schema versions, and externally visible outcomes described by this api block.
- Primary and alternate interfaces, background work, caches, integrations, support paths, and evidence that can exercise the same boundary.
- Adoption-specific configuration, rollout, recovery, and verification responsibilities needed to apply the reference safely.
Outside this block
- Choosing a universal vendor, framework, jurisdiction, numeric threshold, retention period, or service-level objective for every adopter.
- Claiming that packaged scenarios have run against a downstream implementation or that this reference grants legal, security, or accessibility certification.
Contract
- Authorize against the ownership record for upload, read, preview, share, and delete; possession of a URL or key is not authorization.
- Bound size, count, media type, decompression, processing time, and storage consumption before expensive work begins.
- Keep new or suspect objects quarantined until validation and scanning reach a terminal policy outcome.
- Generate object keys independently of user filenames and prevent filenames, MIME labels, and metadata from selecting executable behavior.
- Document method or event semantics, required fields, conditional behavior, limits, and a machine-readable error vocabulary.
- Reject unknown security-sensitive fields and preserve forward compatibility for explicitly extensible data.
- Create an authenticated server-side upload session before issuing a narrowly scoped signed operation bound to object key, method, size, media constraints, owner, and expiry.
- Treat browser transfer as untrusted and incomplete until the server verifies storage version, observed size, digest, type, and scan policy and atomically finalizes ownership.
Implementation guidance
- Publish contract fixtures and consumer tests before routing production traffic to a new version.
- Model Direct browser upload inputs, outputs, actors, states, invariants, side effects, and evidence before selecting framework or vendor details.
- Store the applicable Direct browser upload contract or policy version with material state so migrations, replay, and support decisions remain attributable.
- Introduce the path behind controlled rollout, compare expected and observed outcomes, and keep a tested recovery route until adoption evidence is complete.
Failure handling and safeguards
- Ambiguous processing or ownership leaves the object quarantined; cleanup requires ownership evidence and a recoverable grace period.
- Invalid or contradictory Direct browser upload state is rejected or quarantined; the implementation never guesses a value that broadens authority or duplicates an effect.
- Retries are bounded and use durable identity; after exhaustion, work reaches an inspectable terminal state with an accountable owner.
Verification and operations
- Test retries, duplicate requests, conditional updates, pagination or resumption, invalid credentials, limits, and dependency timeout.
- Monitor Direct browser upload success, denial, validation failure, dependency failure, retry exhaustion, and recovery by contract version without sensitive payload dimensions.
- Re-run paired positive and negative fixtures after policy, schema, dependency, migration, or boundary changes and preserve the resulting evidence.
Adoption assumptions
- Names and values in the example are a concrete fixture, not universal defaults; adopters replace them through documented evidence and ownership.
- The adopting system can provide authenticated identity, durable operation or record versions, bounded telemetry, and a controlled path for change.
The executable-looking examples in this package are fixtures and acceptance contracts. Run the collection validator to check structure and metadata, then translate and execute the scenarios in the target repository before recording implementation evidence.