fix: Prevent double-encoded presigned urls from s3

[AdrianCurtin]

Issue

Closes: #335

With presignedUrl: true, filenames containing URL-sensitive characters were double-encoded, so doc[123].pdf was signed as doc%255B123%255D.pdf and the link failed.

Approach

getFileLocation pre-encodes the filename for the Parse-served and plain S3 URL forms, then reused that already-encoded value as the S3 object key in the presigned branch. The AWS SDK encodes the key again when it builds the signed URL, hence the double encoding.

The presigned branch now builds its key from the raw filename. That also makes it consistent with every other S3 command in the adapter: createFile, deleteFile, getFileData and handleFileStream all pass this._bucketPrefix + filename unencoded. Worth stating plainly, because it makes this more than a cosmetic URL bug: the presigned URL was signed against a key that did not match the key createFile stored the object under, so it pointed at an object that does not exist.

Non-presigned URLs continue to use the pre-encoded fileKey and are unchanged.

Filenames containing / are unaffected. The SDK encodes the key per path segment and preserves the separator, so a raw key is correct there too:

Filename	Presigned URL path
doc[123].pdf	doc%5B123%5D.pdf
folder/doc[123].pdf	folder/doc%5B123%5D.pdf
a b+c&d.pdf	a%20b%2Bc%26d.pdf
héllo.pdf	h%C3%A9llo.pdf

This fix does not depend on any other PR.

Tasks

• Add tests

Summary by CodeRabbit

• Bug Fixes

  • Corrected presigned file links so special characters are encoded only once.
  • Preserved folder paths in presigned links for files stored in nested locations.
  • Improved access to files with brackets, spaces, ampersands, and other special characters.

• Tests

  • Added coverage for special-character filenames and nested file paths.
  • Verified generated links remain valid across supported file naming scenarios.

Related pull requests

These all touch createFile or getFileLocation in index.js. Merging them in this order leaves the fewest conflicts, verified by trial merges of all six together, which pass the suite once resolved:

#336 → #594 → #597 → #591 → #593 → #242

• fix: Prevent double-encoded presigned urls from s3 #336 presigned urls used a pre-encoded key
• fix: Bucket region is ignored, breaking access to buckets in opt-in regions #594 bucket region missing from the direct access url
• feat: Support asynchronous generateKey and validate the generated key #597 asynchronous generateKey
• fix: URL encoding of file location returned by createFile #591 percent-encoding of the Location url
• fix: File location returned by createFile omits the bucket when a custom endpoint is configured #593 Location omitted the bucket for custom endpoints
• feat: Revise createFile logic to return modified filenames and location #242 createFile reporting the stored name and url

#336 and #594 conflict with nothing. The rest collide on the createFile prologue and on the same anchor in spec/test.spec.js, where the conflict truncates each side's block, so the incoming describe has to be re-inserted whole rather than resolved line by line.

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• index.js
• spec/test.spec.js

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---

📝 Walkthrough

Walkthrough

getFileLocation now uses the original filename for presigned S3 requests. Tests cover single encoding of special characters and preservation of nested path separators. Other URL paths remain unchanged.

Changes

Presigned URL encoding

Layer / File(s)	Summary
Presigned URL generation and regression coverage index.js, spec/test.spec.js	Presigned requests use the original filename to prevent double encoding. Tests cover brackets, spaces, ampersands, and nested path separators.

Estimated code review effort: 2 (Simple) | ~7 minutes

Merge Risk: 🔵 Low · up to 51992

The change corrects presigned S3 URLs for URL-sensitive filenames without changing non-presigned URLs. Merge is reasonable with owner awareness that regression coverage should still be expanded for filenames containing spaces and ampersands.

🚥 Pre-merge checks | ✅ 7

✅ Passed checks (7 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title uses the allowed fix: prefix, starts the description with a capital letter, and accurately describes the presigned URL encoding fix.
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check.
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.
Security Check	✅ Passed	The diff only changes the S3 GetObject key from pre-encoded to raw filename; no dependency, credential, authorization, or unsafe execution pattern was introduced, and the repository lists no publis...
Engage In Review Feedback	✅ Passed	GitHub review history shows CodeRabbit requested space/ampersand tests; Adrian added them in commit 5199213 and discussed the stale feedback, with the thread resolved.

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index.js

ESLint skipped: missing config or dependency (missing-dependency). The ESLint configuration references a package that is not available in the sandbox.

spec/test.spec.js

ESLint skipped: the matched ESLint configuration already failed (missing-dependency).

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[coderabbitai]

Actionable comments posted: 0

🧹 Nitpick comments (4)

index.js (4)

231-233: Nit: Clarify naming to reflect semantics (raw/unencoded key)

Consider renaming presignedFileKey to something that conveys the key is unencoded, e.g. rawFileKey or unencodedFileKey, for future maintainability.

Apply this localized rename:

-    const presignedFileKey = `${this._bucketPrefix}${filename}`;
+    const rawFileKey = `${this._bucketPrefix}${filename}`;

Note: See companion change on Line 236 to update the reference.

---

231-236: Nit: Limit scope by computing the raw key only when presigning is enabled

You can avoid an always-on allocation by moving the raw/unencoded key computation inside the if (this._presignedUrl) block, since it’s only used there.

---

236-236: Follow-up: Align variable rename in presign params

If you adopt the naming nit, update the params reference accordingly.

-      const params = { Bucket: this._bucket, Key: presignedFileKey };
+      const params = { Bucket: this._bucket, Key: rawFileKey };

---

231-239: Verify custom baseUrl flows don’t change the canonical path used for signing

When _presignedUrl is true and a custom _baseUrl is provided, buildDirectAccessUrl reconstructs the URL by combining baseUrl + baseUrlFileKey and appending the query from the presigned URL. This remains valid only if the path portion exactly matches the canonical URI used during signing (after encoding). Given your switch to using the unencoded key for signing, this should still match because fileName/fileKey are encoded in the same way. However, configs with _baseUrlDirect and any path rewriting (e.g., CDN origin path or removed bucket prefix) can break signatures.

Please validate these cases:

• Filenames containing spaces, plus signs, percent signs, and unicode (e.g., "a b+%c—µ.png").
• Nested paths in filenames (e.g., "folder/sub/na me.png").
• Configurations with _baseUrl set, both _baseUrlDirect = true and false.
• Non-empty _bucketPrefix, especially when _baseUrlDirect = true.

If any of these alter the path compared to the one used for signing, the signature will be invalid.

I can draft a small set of unit tests (or a minimal Node script) to assert that the constructed URL path exactly equals the presigned URL path for the above cases. Want me to provide that?

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• index.js (1 hunks)

🔇 Additional comments (2)

index.js (2)

231-233: Correct fix to avoid double-encoding during presign

Using the original, unencoded filename for the presigned S3 GetObjectCommand key is the right approach. The AWS presigner handles URL encoding; passing an already-encoded key led to double-encoding. This aligns with the PR objective and should resolve #335.

---

236-236: Update presign params to use the raw/unencoded key

Switching the presign GetObjectCommand to the unencoded key is correct and matches S3 expectations.

[coderabbitai]

Actionable comments posted: 1

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Inline comments:
In `@spec/test.spec.js`:
- Around line 648-655: Add regression cases alongside the existing
specialFilename test for filenames containing a space and an ampersand, such as
doc 123.pdf and doc&123.pdf. Assert that each file location contains the
correctly encoded filename and does not contain a double-encoded form, matching
the existing bracket test pattern.

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[AdrianCurtin]

@mtrezza

I think this one should be merged probably some time ago unless there's something else I'm missing here. But looking forward to seeing it go through!

[AdrianCurtin]

@coderabbitai review

The "Engage In Review Feedback" pre-merge check is reading an earlier state of this PR. It says the branch "adds only bracket and nested-path cases", but the space and ampersand cases landed in 5199213, which is the current head:

Filename	Encoded once	Double encoded
doc[123].pdf	doc%5B123%5D.pdf	doc%255B123%255D.pdf
doc 123.pdf	doc%20123.pdf	doc%2520123.pdf
doc&123.pdf	doc%26123.pdf	doc%2526123.pdf

The review thread that raised it is resolved, and you confirmed there that the table-driven cases cover the requested regressions.

Re-verified on the current head: the suite and lint both pass, and the cases are not vacuous, since reverting index.js to Key: fileKey fails all three and restoring it passes them.

[coderabbitai]

🧩 Analysis chain

🏁 Script executed:

#!/bin/bash
set -euo pipefail

printf '%s\n' '== Current commit =='
git rev-parse --short HEAD
git log -1 --format='%H%n%s'

printf '%s\n' '== Changed files against PR base (if available) =='
git diff --name-status HEAD^ 2>/dev/null || true

printf '%s\n' '== Source outline =='
ast-grep outline index.js --items all --type function --match 'getFileLocation' --view expanded || true

printf '%s\n' '== getFileLocation implementation and test cases =='
rg -n -A100 -B10 '\b(getFileLocation|presignedFileKey|doc\[123\]\.pdf|doc 123\.pdf|doc&123\.pdf|nested)\b' index.js spec/test.spec.js || true

printf '%s\n' '== Relevant current diff =='
git diff HEAD^ -- index.js spec/test.spec.js 2>/dev/null || true

Length of output: 27738

---

@AdrianCurtin The current head is 5199213. The earlier feedback is stale.

index.js passes the raw filename to GetObjectCommand for presigned URLs. The non-presigned path still uses the encoded fileKey.

The current table-driven test covers all three requested cases:

• Brackets: doc[123].pdf
• Spaces: doc 123.pdf
• Ampersands: doc&123.pdf

The separate nested-path test also verifies that / remains a path separator. Static inspection confirms that reverting to Key: fileKey would cause the single-encoding assertions to fail.

I did not independently run the suite or lint in this sandbox. I will review the current PR head.

---

🧠 Learnings used

Learnt from: mtrezza
Repo: parse-community/parse-server-s3-adapter PR: 459
File: index.js:184-209
Timestamp: 2026-02-21T03:23:01.721Z
Learning: In the parse-server-s3-adapter repository, the `Location` field returned by `createFile()` in `index.js` intentionally uses raw `params.Key` without URL encoding to maintain pre-existing behavior. This is consistent across both buffer and streaming upload paths. Any URL encoding improvements should be addressed separately and should use `params.Key.split('/').map(encodeURIComponent).join('/')` to avoid encoding path separators.

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[AdrianCurtin]

@coderabbitai full review pls

[coderabbitai]

@AdrianCurtin I will perform a full review of the current PR head.

✅ Action performed

Full review finished.

[AdrianCurtin]

@mtrezza , i think this one can just go?
It's a single line change w/ regression coverage.
Not a cosmetic bug at all