[eisen0419]

Fixes #675
Fixes: #675

Proposed Changes

Align HTTP protocol binding media-type matching, falsy JSON data handling, and ce- header percent-encoding/decoding with the CloudEvents HTTP Protocol Binding v1.0.2 specification.

Summary

 HTTP.toEvent / HTTP.binary / HTTP.structured
   getMode(headers)
-    startsWith("application/cloudevents") -> Mode.STRUCTURED
+    contentTypeEssence(ct)                # trim + lowercase + strip "; ..." params
+    startsWith("application/cloudevents-batch") -> Mode.BATCH
+    startsWith("application/cloudevents")       -> Mode.STRUCTURED
   parserForContentType(ct)
+    exact registered key -> essence key -> parameterized match -> */json | */*+json
   parseStructured / JSONParser.parse
-    if (payload[key]) eventObj[key] = ... # dropped 0, false, "", null
+    if (hasOwnProperty && payload[key] !== undefined) eventObj[key] = ...
+    JSON.parse(payload) first; quote only legacy non-JSON bare strings
   headers (ce-*)
+    encode: UTF-8 percent-encode SP, '"', '%', and outside U+0021..U+007E
+    decode: trim OWS -> unwrap single quoted-string -> single UTF-8 percent-decode

Description

1. Content-Type media-type normalization (§3 / §3.1.1 / §3.2.1): Extract the normalized type/subtype essence (case-insensitive, parameters stripped, OWS trimmed) when selecting structured/batch/binary mode and resolving parsers, while still honoring custom entries registered on parserByContentType. application/cloudevents-batch* is classified before application/cloudevents*, and unregistered type/json or type/*+json media types fall back to JSONParser.
2. Falsy JSON data and JSON primitives: Preserve 0, false, "", and null in structured mode instead of dropping falsy values, and parse valid JSON primitives in JSONParser.parse before falling back to legacy raw-string quoting.
3. ce- header percent-encoding (§3.1.3.2): Percent-encode string ce- header values on egress (including non-ASCII UTF-8 such as €, spaces, ", %, and control characters, preventing Node ERR_INVALID_CHAR in httpTransport) and decode incoming ce- headers via OWS trim, optional RFC 7230 quoted-string unescaping, and a single fatal UTF-8 percent-decode pass (ValidationError on malformed UTF-8).

Evidence

• Before:
  • HTTP.toEvent({ headers: { "content-type": "application/cloudevents+json; charset=UTF-8" }, body }) threw ValidationError: Missing required attributes: id, source, type (fell through to binary mode) or Unsupported content type.
  • Structured events with data: 0, false, "", or null returned event.data === undefined; binary JSON bodies "0", "false", "null" stayed strings.
  • emitterFor(httpTransport(...))(new CloudEvent({ ..., subject: "Euro €" })) threw TypeError [ERR_INVALID_CHAR]: Invalid character in header content ["ce-subject"].
• After:
  • npm test passes cleanly (remark, eslint, schema build, tsc, webpack browser bundle, all 7 conformance scenarios / 38 steps, and 281 Mocha tests including test/integration/http_binding_interop_test.ts).

Merge Danger

Door: Two-way

Self-contained changes in universal HTTP message/header/parser helpers (src/parsers.ts, src/message/http/index.ts, src/message/http/headers.ts) with no public API signature changes or new dependencies.

Blast Radius: Narrow

Scoped to HTTP binding header serialization/parsing and JSONParser media-type lookup; existing custom parserByContentType overrides, binary Buffer passthrough, non-string boolean/integer extension headers, and Kafka/MQTT bindings remain unchanged.