fix: case-insensitive Link rel="alternate" per RFC 8288#72
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RFC 8288 §2.1.1 states that relation types are case-insensitive. _parse_link_alternates() was using a case-sensitive regex, which could miss alternate certificate chains from ACME servers that send Rel="Alternate" or similar variants. Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
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What
Make
_parse_link_alternates()match therel="alternate"link relation type case-insensitively.Why
RFC 8288 §2.1.1 states that relation types are not case-sensitive. The previous regex required exact lowercase
rel="alternate", which could miss alternate certificate chains from ACME servers that sendRel="Alternate"orREL="ALTERNATE". While Let's Encrypt uses lowercase, other ACME CAs (ZeroSSL, Google Trust, Buypass) may not.How
Added the
/iflag to the Link header regex in_parse_link_alternates().Testing
Added
t/Net-ACME2-link-alternates.twith 8 tests covering: no header, single/multiple alternates, mixed case (Alternate,ALTERNATE), non-alternate links filtered, whitespace variations. Full test suite passes.🤖 Generated with Claude Code