Merge R2 upload & multipart docs

[ask-bonk]

All tasks are complete. Here's a summary of everything done:

Changes summary

Consolidated upload docs into a single page (/r2/objects/upload-objects/)

Restructured src/content/docs/r2/objects/upload-objects.mdx from a basic upload page into a comprehensive upload guide that merges content from the old multipart-objects.mdx page:

• Added a comparison table at the top ("Choose an upload method") that helps users immediately understand when to use single upload vs. multipart upload, covering: best-for use cases, max object size, part sizes, resumability, parallelism
• Workers API section with:
  • Single put() example with httpMetadata
  • Simple multipart example showing createMultipartUpload() / uploadPart() / complete() / abort() lifecycle
  • Full HTTP API Worker example for client-driven multipart uploads (cleaned up from the old workers-multipart-usage page)
  • Presigned URL example using aws4fetch (Workers-compatible)
• S3 API section with TypeScript, JavaScript, and Python tabs for:
  • Single upload (PutObjectCommand / put_object)
  • Automatic multipart upload (@aws-sdk/lib-storage Upload / upload_file)
  • Manual multipart upload (low-level CreateMultipartUpload / UploadPart / CompleteMultipartUpload with proper abort-on-error)
  • Presigned URL generation (getSignedUrl / generate_presigned_url)
• Multipart upload details section preserving the important reference material from the old page (part size limits, lifecycle policies, ETag calculation)
• Related resources section with LinkCards

Deleted src/content/docs/r2/objects/multipart-objects.mdx

Updated public/__redirects

• Added: /r2/objects/multipart-objects/ /r2/objects/upload-objects/ 301

Updated 3 files with internal links

• src/content/release-notes/r2.yaml - Updated multipart ETags link
• src/content/partials/r2/migrator-etag-caveat.mdx - Updated ETag calculation link
• src/content/docs/r2/api/error-codes.mdx - Updated multipart upload link

Closes #28184

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[github-actions]

This PR requires additional review attention because it affects the following areas:

Redirects

This PR changes current filenames or deletes current files. Make sure you have redirects set up to cover the following paths:

• /r2/objects/multipart-objects/

Partials

This PR updates partial files, which are pieces of content used across multiple files in our Render component.

• r2/migrator-etag-caveat - view affected files

[github-actions]

This pull request requires reviews from CODEOWNERS as it changes files that match the following patterns:

Pattern	Owners
/public/__redirects	@cloudflare/content-engineering, @cloudflare/pcx-technical-writing
/src/content/docs/r2/	@oxyjun, @elithrar, @jonesphillip, @aninibread, @harshil1712, @cloudflare/workers-docs, @cloudflare/pcx-technical-writing
/src/content/partials/r2/	@elithrar, @rita3ko, @irvinebroque, @vy-ton, @cloudflare/pcx-technical-writing
/src/content/release-notes/r2.yaml	@oxyjun, @elithrar, @aninibread, @cloudflare/workers-docs, @cloudflare/pcx-technical-writing

[elithrar]

Cc @aninibread @jonesphillip

[ask-bonk]

Here's a summary of my rigorous review and the fixes I applied:

---

Code review summary

I reviewed all 8 code examples (12 language variants total) against the criteria: concise, safe to copy+paste, error handling, and best practices.

Issues found and fixed

#	Example	Issue	Severity
1	Workers single upload	No error handling; object?.key silently returns null properties with 200 status	High
2	Workers multipart	firstChunk and secondChunk are undefined variables -- code throws ReferenceError if copy+pasted	High
3	Workers presigned URL	Hardcoded credentials in top-level scope (not in env); not wrapped in a Worker handler unlike every other Workers example; no output	High
4	S3 manual multipart (all 3 langs)	abort() in catch block can itself throw, masking the original error	Medium
5	S3 auto multipart (TS/JS)	progress.total is undefined for streams -- log prints "undefined"	Medium
6	All Workers examples	Unused ctx: ExecutionContext parameter	Low
7	TS single upload	Unnecessary Buffer type annotation	Low
8	S3 examples	No visible output -- user can't tell if script succeeded	Low

What was already good

• Workers HTTP API multipart example (lines 116-190): Input validation, try/catch on each operation, proper use of resumeMultipartUpload(). This was the strongest example.
• S3 manual multipart structure: Correct try/catch + abort pattern, proper part tracking, correct createReadStream options with inclusive end.
• API usage is correct: httpEtag used for HTTP headers, etag used for JSON responses, R2UploadedPart[] type correctly used.
• Python examples: Clean, idiomatic, correct use of context managers.

Remaining notes (no fix needed)

• The S3 presigned URL examples are script-style (no function wrapper) which is intentionally different from Workers examples -- this is correct since they're meant to run as server-side Node.js/Python scripts.
• The <ACCOUNT_ID>, <ACCESS_KEY_ID>, <SECRET_ACCESS_KEY> placeholder pattern is consistent across all examples and follows Cloudflare docs conventions.

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[github-actions]

Preview URL: https://b24c9ff3.preview.developers.cloudflare.com
Preview Branch URL: https://opencode-issue28184-20260208155556.preview.developers.cloudflare.com

Files with changes (up to 15)

Original Link	Updated Link
https://developers.cloudflare.com/r2/objects/upload-objects/	https://opencode-issue28184-20260208155556.preview.developers.cloudflare.com/r2/objects/upload-objects/
https://developers.cloudflare.com/r2/objects/multipart-objects/	https://opencode-issue28184-20260208155556.preview.developers.cloudflare.com/r2/objects/multipart-objects/
https://developers.cloudflare.com/r2/api/error-codes/	https://opencode-issue28184-20260208155556.preview.developers.cloudflare.com/r2/api/error-codes/

[ask-bonk]

Here's a summary of the changes:

Converted all 4 Workers API code blocks to use <TypeScriptExample>:

1. Single upload (line 50) -- put() example
2. Simple multipart upload (line 84) -- createMultipartUpload() example
3. HTTP API multipart (line 123) -- full client-driven multipart Worker
4. Presigned URLs (Workers) (line 207) -- aws4fetch presigned URL example

Each bare ```ts block is now wrapped in <TypeScriptExample> ... </TypeScriptExample>, which will auto-generate a JavaScript tab by stripping TypeScript annotations via ts-blank-space and formatting with Prettier. The TypeScriptExample import was added to the frontmatter imports.

The S3 API section examples were intentionally left as manual <Tabs>/<TabItem> because they include Python variants alongside TypeScript/JavaScript, which TypeScriptExample doesn't support.

Note: A full build couldn't run in this CI environment due to a Node.js version mismatch (requires Node 22.x, has 20.x), but the changes follow the exact same pattern used across 100+ other MDX files in the codebase.

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[elithrar]

/bonk run a final review and ensure all code examples meet our bar.

[ask-bonk]

Final review: All code examples meet the bar

I reviewed all 12 code examples (8 blocks, 12 language variants) across the file plus the surrounding infrastructure (redirects, links, components). Here's the summary:

Code examples -- all pass

#	Example	Lines	Verdict
1	Workers single put()	52-76	Correct. Null check for precondition failure, try/catch, streams request.body directly.
2	Workers simple multipart	86-117	Correct. Placeholder data with comments, abort-on-failure, httpEtag for response headers (recommended by Cloudflare).
3	Workers HTTP API multipart	125-197	Correct. Input validation, resumeMultipartUpload() used synchronously (no await -- correct since it's not async), proper R2UploadedPart[] typing, per-action error handling.
4	Workers presigned URL (aws4fetch)	209-239	Correct. Credentials from env, signQuery: true for query-string signing, X-Amz-Expires as query param.
5	S3 single upload (TS/JS/Python)	254-333	Correct. readFile/open("rb"), PutObjectCommand/put_object, ETag output.
6	S3 automatic multipart (TS/JS/Python)	347-437	Correct. @aws-sdk/lib-storage Upload with leavePartsOnError: false, progress.loaded ?? 0 (handles undefined), upload_file for Python.
7	S3 manual multipart (TS/JS/Python)	447-657	Correct. createReadStream with inclusive end - 1, ContentLength specified, abort in nested try/catch (best-effort cleanup), re-throws original error.
8	S3 presigned URL (TS/JS/Python)	667-752	Correct. getSignedUrl/generate_presigned_url, expiresIn: 3600.

Infrastructure -- all pass

• TypeScriptExample components: All 4 Workers examples correctly use <TypeScriptExample> wrapping ```ts fenced blocks, matching the pattern used across 500+ other files in the codebase.
• Redirect: /r2/objects/multipart-objects/ /r2/objects/upload-objects/ 301 is in public/__redirects at line 1588.
• Deleted file: multipart-objects.mdx no longer exists.
• Internal links: Zero remaining references to /r2/objects/multipart-objects/ anywhere in src/. The release notes and partial files both updated to point to /r2/objects/upload-objects/#etags.
• S3 tabs: Correctly use manual <Tabs>/<TabItem> (not TypeScriptExample) since they include Python, which TypeScriptExample doesn't support.

No changes needed

All examples are correct, safe to copy-paste, handle errors properly, and follow best practices for their respective languages/SDKs. The previous review rounds caught and fixed the real issues (undefined variables, hardcoded credentials, missing error handling). This PR is in good shape.

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