Encode '+' in URL path segments to support SemVer build metadata

[VijayabaskarR-06]

Semantic Versioning lets us use "+" for build metadata (like 1.0.0+10), but AWS S3 sees "+" as a space even in URL path segments, which causes 403 errors when we try to access extension resources. This change makes sure that '+' is always encoded as '%2B' when building API URLs in UrlUtil.createApiUrl. This keeps Semantic Versioning the same.

In short It was possible to publish extensions that used Semantic Versioning with build metadata (for example, 1.0.0+10), but later they wouldn't load or download, which caused 403 errors. The + sign in URLs is treated as a space by AWS S3, even in path segments.

UriUtils.encodePathSegment not encoding the + character when making API URLs was the cause of the problem. Because of this, URLs with versions that had + were made wrong for resources that were backed by S3. When making URL path segments, this change fixes the problem by explicitly encoding + as %2B in UrlUtil.createApiUrl. The fix is applied in one place, so it affects all API URLs in the same way, without changing Semantic Versioning.

[netomi]

I tried that approach already and it leads to spring automatically encoding the % again. So a fix would need to change the default spring behavior.

[VijayabaskarR-06]

Thanks I see that pre-encoding causes double-encoding due to Spring’s default behaviour.
I’ll update the fix to rely on Spring’s path-segment encoding instead of manual %2B, so the + is encoded correctly without being re-escaped