fix(triple): canonicalize context metadata headers

[leno23]

What

Canonicalize Triple context metadata header keys when storing incoming and outgoing headers. This keeps NewOutgoingContext and AppendToOutgoingContext values under the same key and makes standard http.Header.Get/Values access work as documented.

Also document how unary clients read response headers and trailers from the response wrapper.

Refs #2422

Validation

• go test ./protocol/triple/triple_protocol
• go test ./protocol/triple
• git diff --check

[codecov-commenter]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 53.55%. Comparing base (60d1c2a) to head (7fd64c2).
⚠️ Report is 845 commits behind head on develop.

Additional details and impacted files

@@             Coverage Diff             @@
##           develop    #3428      +/-   ##
===========================================
+ Coverage    46.76%   53.55%   +6.78%     
===========================================
  Files          295      493     +198     
  Lines        17172    38386   +21214     
===========================================
+ Hits          8031    20557   +12526     
- Misses        8287    16176    +7889     
- Partials       854     1653     +799     

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[Copilot]

Pull request overview

This PR canonicalizes Triple context metadata header keys when storing incoming/outgoing headers so that headers added via NewOutgoingContext and AppendToOutgoingContext unify under the same key and can be reliably accessed via standard http.Header methods (e.g., Get/Values). It also clarifies how unary clients can read response headers and trailers from the response wrapper.

Changes:

• Canonicalize context metadata keys using http.CanonicalHeaderKey in outgoing/incoming context helpers.
• Make IsReservedHeader case-insensitive by lowercasing input before classification, with a focused unit test.
• Add documentation/examples for response header/trailer access and outgoing context usage.

Reviewed changes

Copilot reviewed 7 out of 7 changed files in this pull request and generated 1 comment.

Show a summary per file

File	Description
protocol/triple/triple_protocol/triple.go	Documents unary client usage for reading response headers/trailers via the response wrapper.
protocol/triple/triple_protocol/protocol_grpc.go	Lowercases inputs in IsReservedHeader to ensure reserved-header detection is case-insensitive.
protocol/triple/triple_protocol/protocol_grpc_test.go	Adds a test ensuring IsReservedHeader canonicalizes (lowercases) input.
protocol/triple/triple_protocol/header.go	Canonicalizes stored context header keys (incoming/outgoing) and aligns append behavior.
protocol/triple/triple_protocol/header_test.go	Adds an example verifying outgoing context + append results are accessible via Get/Values.
protocol/invocation/rpcinvocation.go	Lowercases extracted header keys before storing as invocation attachments for consistency.
protocol/invocation/rpcinvocation_test.go	Updates assertions to use http.Header.Values instead of direct map indexing.

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[Alanxtl]

This looks like a reasonable compromise to me. Since these APIs expose http.Header, storing context headers in canonical form makes standard Header.Get/Values work as users would expect. At the same time, converting keys back to lowercase when merging into Invocation attachments keeps the Dubbo/gRPC metadata semantics aligned with grpc-go, dubbo-java, and HTTP/2 wire behavior.

Could we add a short comment around the CanonicalHeaderKey / ToLower boundary to make this intentional layering explicit? Something like: context headers use canonical http.Header keys for Go API compatibility, while invocation attachments remain lowercase metadata keys for Dubbo/gRPC compatibility.

[leno23]

Added short comments around the canonical context-header storage and lowercase exported-attachment boundary in 7fd64c2. Local validation passes: go test ./protocol/triple/triple_protocol, git diff --check, and golangci-lint run ./protocol/triple/triple_protocol --timeout=10m.

[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud

[Alanxtl]

lgtm