Guard download headers for R2 public URLs

[Copilot]

Canvas downloads failed because the client always attached Pollinations API auth headers to R2 public URLs, triggering CORS/403 errors. This update makes header usage conditional so R2 downloads succeed without changing the canvas flow.

• Download fetch routing
  • Detect Pollinations API URLs and only attach Authorization headers for those endpoints.
  • Use plain fetch for R2/public URLs to avoid preflight or auth rejection.
• Download behavior
  • Preserve existing blob handling and browser download trigger logic.
• Tests
  • Added coverage in lib/api/image-api.test.ts for Pollinations vs non-Pollinations download header handling.

const headers = isPollinationsUrl(imageUrl)
  ? PollinationsAPI.getHeaders()
  : undefined

const response = await fetch(imageUrl, headers ? { headers } : undefined)

Original prompt

Right now people see an error when ckicking the download icon when hovering over a generated image or video on the canvas. It should be downloading from the r2 storage with no issues.

Please identify the root cause by analyzing the canvas code and sureounding code context to understand the flow of data and apply the minimal best practice fix.

---

💬 We'd love your input! Share your thoughts on Copilot coding agent in our 2 minute survey.

[vercel]

The latest updates on your projects. Learn more about Vercel for GitHub.

Project	Deployment	Review	Updated (UTC)
bloomstudio	Ready	Preview, Comment	Jan 21, 2026 8:29am

[Simplereally]

@copilot Yep sounds reasonable. Document the code as well to explain the fix.

[Copilot]

@copilot Yep sounds reasonable. Document the code as well to explain the fix.

Added inline documentation explaining the Pollinations-only header guard and updated tests accordingly. Commit: daecddf.

[coderabbitai]

Important

Review skipped

Bot user detected.

To trigger a single review, invoke the @coderabbitai review command.

You can disable this status message by setting the reviews.review_status to false in the CodeRabbit configuration file.

---

_{Comment @coderabbitai help to get the list of available commands and usage tips.}