Validate HTTP method and status semantics independently of wire version

Keep this document to one review outcome: Validate HTTP method and status semantics independently of wire version. Only the official source and traced locations below supply facts. Confirm applicability before acting.

Source fact:

The official RFC 9110 — HTTP Semantics from RFC Editor / Internet Engineering Task Force supports the following bounded statements:

• HTTP’s core semantics do not change between protocol versions even though their wire expression can change; methods, status codes, and other generic extension points retain their semantics across versions. The research record locates this support at Sections 2.5 (Protocol Version) and 16 (Extending HTTP).
• The method token is case-sensitive and supplies the primary request semantics; an unrecognized or unimplemented method should receive 501, while a known method disallowed for the resource should receive 405. The research record locates this support at Section 9.1 (Overview).
• A client MUST understand every status-code class and treat an unrecognized status as that class’s x00 code; values outside 100 through 599 are invalid. The research record locates this support at Section 15 (Status Codes).

The source support ends with the statements listed above. Use them to examine clients, origin services, intermediaries, caches, proxies, gateways, protocol versions, and security-policy enforcement points in the applicable environment, not to imply a wider guarantee.

What the source does not establish

This RFC evidence supports only the named web or transport decision; it does not prove browser, intermediary, library, or service compatibility. It does not establish a deployment’s current state, authorize a production change, prove compliance, or show that DNS, certificates, identity providers, time, content delivery, network paths, and application ownership are healthy. Documented options are review inputs, not universal mandates.

Applicability questions

• For source statement 1 at Sections 2.5 (Protocol Version) and 16 (Extending HTTP), which observable configuration, record, or test can confirm applicability here?
• For source statement 2 at Section 9.1 (Overview), which observable configuration, record, or test can confirm applicability here?
• For source statement 3 at Section 15 (Status Codes), which observable configuration, record, or test can confirm applicability here?
• What inventory proves which parts of clients, origin services, intermediaries, caches, proxies, gateways, protocol versions, and security-policy enforcement points are in and out of scope?
• Which condition in DNS, certificates, identity providers, time, content delivery, network paths, and application ownership must be healthy before evidence is trustworthy?
• What result would disprove the working assumption and return the issue to the owner?

DSE recommendation:

DSE recommends using the cited source as the evidence anchor for this decision. Make the source, asset scope, owner, and expected outcome explicit in the review record. Record the source location, examined part of clients, origin services, intermediaries, caches, proxies, gateways, protocol versions, and security-policy enforcement points, observed and expected states, owner, and reason for deviation.

Do not move from citation to production in one step. Pilot the decision where practical, observe agreed signals, retain a reversal point, and verify DNS, certificates, identity providers, time, content delivery, network paths, and application ownership. Handle credentials, keys, recovery data, and personal information through approved secure channels.

Verification and evidence

Tie each conclusion back to Sections 2.5 (Protocol Version) and 16 (Extending HTTP); Section 9.1 (Overview); Section 15 (Status Codes) and to observable material such as request and response captures, negotiated protocol details, headers, cache behavior, certificate state, and server or proxy logs. Preserve provenance and stable identifiers without copying secrets into the evidence set.

Close the review only when the evidence, exception handling, resulting action, and after-state are linked. Schedule a new review after material technical, organizational, incident, or source changes; today’s observation is not a continuing guarantee.

Official references

• RFC 9110 — HTTP Semantics — RFC Editor / Internet Engineering Task Force