feat: output.getDownloadUrl() + SDK User-Agent identification

[wei-hai]

What

• Output.getDownloadUrl(): Promise<{ url, expiresAt }> — a directly-fetchable URL for an output, so a caller (e.g. a Cloudflare/serverless worker) can hand the URL to a downstream consumer without streaming the bytes through itself.
  • Object-storage backends (Cloud/serverless): the self-authorizing signed URL (from the content endpoint's redirect Location) + its expiry.
  • Self-hosted (proxy serves inline): the content-endpoint URL, expiresAt: null.
  • Works on every backend and never throws (write-once/run-anywhere). Short-lived, self-authorizing bearer credential.
  • Per-output: a multi-output job resolves each output to its own distinct URL.
• User-Agent on every request: comfy-sdk-typescript/{version} (node {version}), with an optional clientInfo appending app/{name}. Request metadata, not telemetry.

How

New getAssetContentUrl() fetches GET /assets/{id}/content with redirect: "manual" (the existing getAssetContent still uses follow), reads the Location without following it (bearer can't leak cross-origin), and parses GCS V4 X-Goog-Date/X-Goog-Expires for the expiry.

Tests

vitest run --coverage — 128 passed (incl. cloud-redirect, self-hosted-inline, multi-output-distinct-URLs, bearer-not-leaked, User-Agent + clientInfo). tsc + oxlint + oxfmt clean. Not added to OPERATION_IDS (a second low method over the same operation, not a new operationId).

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Review details

⚙️ Run configuration

Configuration used: Organization UI

Review profile: ASSERTIVE

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Run ID: 8935f890-52b4-4cf8-b22a-a50429180b01

📥 Commits

Reviewing files that changed from the base of the PR and between 1ae77a9 and f8869b4.

📒 Files selected for processing (2)

• src/low/transport.test.ts
• src/low/transport.ts

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📝 Walkthrough

Walkthrough

The SDK adds asset download URL resolution with redirect and expiry handling, configurable User-Agent metadata, clientInfo wiring, and an Output.getDownloadUrl() helper. Tests cover redirect security, backend variants, multiple outputs, and header behavior.

Changes

Asset URLs and User-Agent Metadata

Layer / File(s)	Summary
Transport asset URL resolution src/low/transport.ts, src/low/index.ts, src/low/transport.test.ts, test/support/stub-server.ts	Adds manual redirect handling, signed URL expiry parsing, typed asset URL results, and coverage for redirect, self-hosted, error, and authorization behavior.
Client User-Agent propagation src/low/transport.ts, src/sdk/client.ts, src/low/transport.test.ts, test/support/stub-server.ts, README.md	Builds default SDK User-Agent values, appends clientInfo, preserves explicit headers, wires client options through the SDK, and documents the behavior.
Output download URL API src/sdk/outputs.ts, src/sdk/outputs.test.ts	Adds Output.getDownloadUrl() and validates distinct URLs and expiry values across backend responses and output IDs.

Sequence Diagram(s)

sequenceDiagram
  participant Output
  participant ComfyLow
  participant AssetEndpoint
  Output->>ComfyLow: getAssetContentUrl(assetId)
  ComfyLow->>AssetEndpoint: GET asset content with redirect: manual
  AssetEndpoint-->>ComfyLow: content response or redirect Location
  ComfyLow-->>Output: downloadable URL and expiresAt

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🚥 Pre-merge checks | ✅ 2

✅ Passed checks (2 passed)

Check name	Status	Explanation
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.

✨ Finishing Touches

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• Create PR with unit tests
• Commit unit tests in branch feat/output-get-download-url

✨ Simplify code

• Create PR with simplified code
• Commit simplified code in branch feat/output-get-download-url

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[coderabbitai]

Actionable comments posted: 2

🤖 Prompt for all review comments with AI agents

Verify each finding against current code. Fix only still-valid issues, skip the
rest with a brief reason, keep changes minimal, and validate.

Inline comments:
In `@src/low/transport.ts`:
- Around line 36-41: The hand-maintained SDK_VERSION constant can diverge from
package.json without detection. Add a focused test that reads package.json and
asserts its version equals SDK_VERSION, so any version bump missing from the
constant fails immediately.
- Around line 352-371: Update getAssetContentUrl so the inline 200/206 response
body is consumed or destroyed before returning the local URL result, while
preserving the existing redirect handling and return values. Ensure the response
connection is released even when the inline response has a body.

🪄 Autofix (Beta)

Fix all unresolved CodeRabbit comments on this PR:

• Push a commit to this branch (recommended)
• Create a new PR with the fixes

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ℹ️ Review info

⚙️ Run configuration

Configuration used: Organization UI

Review profile: ASSERTIVE

Plan: Pro Plus

Run ID: 39db2493-b8f0-4a0e-83aa-307bdad5a806

📥 Commits

Reviewing files that changed from the base of the PR and between 5f7c428 and 1ae77a9.

📒 Files selected for processing (8)

• README.md
• src/low/index.ts
• src/low/transport.test.ts
• src/low/transport.ts
• src/sdk/client.ts
• src/sdk/outputs.test.ts
• src/sdk/outputs.ts
• test/support/stub-server.ts