fix: Bucket region is ignored, breaking access to buckets in opt-in regions - #594

Issue

Closes: #139
Closes: #595

A bucket in a region that is not enabled by default, ap-east-1 in the report, uploads fine but the url handed back is unusable. The configured region was being lost in two independent places, and the issue only closes when both are fixed.

The direct access url omitted the region. getFileLocation returned https://<bucket>.s3.amazonaws.com/<key>. The global endpoint does not reach buckets in opt-in regions, so the url resolves to nothing for exactly the regions in the report.

The region never arrived in the first place, for two of the three constructor forms. optionsFromArguments copies an explicit list of fields out of the options object for the string and positional forms, and region is the only field in the defaults list that is missing from that copy list. It silently fell back to us-east-1:

new S3Adapter('key', 'secret', 'bucket', { region: 'ap-east-1' })._region  // us-east-1
new S3Adapter('bucket', { region: 'ap-east-1' })._region                   // us-east-1
new S3Adapter({ bucket: 'bucket', region: 'ap-east-1' })._region           // ap-east-1

Approach

The url now carries the region, and region is copied like every other option. All four forms, including the default, resolve correctly after the change.

Compatibility

Two behavior changes worth stating rather than leaving to be discovered.

The direct access url changes host for every deployment using directAccess without a baseUrl, from <bucket>.s3.amazonaws.com to <bucket>.s3.<region>.amazonaws.com. Both forms work for regions enabled by default, so this is not a break, but it is visible to anyone pinning that hostname in a CDN origin or a CORS allowlist. Three existing assertions are updated accordingly.

This is better read as removing an inconsistency than as inventing a url shape: the presigned test already expected my-bucket.s3.us-east-1.amazonaws.com, because the SDK builds that url itself. The same adapter was returning two different hosts for the same object depending on whether presignedUrl was set. They now agree.

The options fix changes where the S3 client points, not just a url. Anyone who declared a non-default region through the string or positional form has been running against us-east-1 without knowing, and will now get the region they asked for. That is the intent, but it is a change for a configuration that was silently wrong. The exposed population should be very small, since writing to the wrong region fails with PermanentRedirect, so such a setup is generally already broken.

Tests

• A direct access url for a bucket in ap-east-1, the case from the report.
• The region surviving each constructor form, and still defaulting when the options object omits it.
• Three existing direct access assertions updated to the regional host.

Full suite passes.

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.

#593 and #594 now overlap. Both write the direct access host in getFileLocation, #594 as https://${bucket}.s3.${region}.amazonaws.com and #593 as _buildLocationBase(), and both update the three should go directly to amazon assertions. Keep _buildLocationBase(), which already includes the region and additionally handles custom endpoints. Same behavior for the default case, so the resolution is mechanical.