B2 doesn't map onto the generic-S3 "paste an endpoint" model: its S3-compatible
endpoint is region-scoped (s3.<region>.backblazeb2.com) and a public bucket is
addressed virtual-hosted-style, so the public download URL is
https://<bucket>.s3.<region>.backblazeb2.com/<key> — not derivable from a pasted
generic endpoint. So B2 silently failed under "Custom S3".
- s3-url: deriveB2Endpoint(region) -> https://s3.<region>.backblazeb2.com (empty for
auto/blank/pasted-host so callers can require a real region); re-exported from
s3Service.
- storageService: PROVIDERS.B2 + resolveB2Endpoint (explicit endpoint wins, else
derive) + PROVIDER_TESTS[B2] (derived endpoint, forcePathStyle false).
- Public URL = S3-style virtual-hosted, auto-derived; an explicit Public Access URL
(custom domain/CDN) overrides it. The save path now forwards the user's public URL
to prepareS3Connection (also fixes generic-S3 ignoring a custom CDN URL when blank
-> still derives, so no regression).
- UI: "Backblaze B2" provider option + helper; raw Endpoint hidden for B2 (region
drives it), region shows a us-west-004 example, force-path-style toggle hidden;
save/test derive endpoint from region with a clear "enter your region" error.
UploadModal shows B2-specific labels.
- Tests: tests/storage-b2-provider.test.mjs (8). All s3/storage suites green (50);
build + lint clean.
Co-Authored-By: Claude Opus 4.8 <[email protected]>
