Vary Name Set Audit

Description

Audit explicit Vary field-name set duplicates and mixed wildcard use under HTTP case-insensitive names; no header-line parser or policy repair.

HTTP caches distinguish storage policy, freshness and validation. Age and freshness lifetime are durations in seconds; an entity tag is an opaque validator that can be marked weak. Vary identifies request fields relevant to representation selection. A focused arithmetic or token check alone does not decide whether a stored response may be reused.

Audit explicit Vary field-name set duplicates and mixed wildcard use under HTTP case-insensitive names; no header-line parser or policy repair.

When to use this tool

Use this tool to audit explicit Vary field-name set duplicates and mixed wildcard use under HTTP case-insensitive names; no header-line parser or policy repair.

How to use the tool and how it works

Enter names using the input definitions below.
Run the operation. Resolve malformed-input errors before interpreting the result.
Read result.duplicates, result.wildcard, result.wildcardMixed. Interpret signs, units, ordering and null values using the rules below.

Validate each name as an HTTP token or star. Group case-insensitive duplicates, report wildcard presence, and flag wildcardMixed when star occurs with another distinct normalized name.^{[1, 2]}

Input field	Meaning and units	Accepted input
names	Explicit Vary field-name strings or star; casing is preserved as occurrence evidence.	Dense list of at most 128 strings, each at most 8,192 UTF-16 code units.

Output field	Interpretation
result	Object containing the fields below.
result.duplicates	Case-insensitive repeated field-name groups with original indexes.
result.wildcard	Whether any exact star name occurs.
result.wildcardMixed	Whether star occurs with another distinct normalized name.

json

{
  "input": {
    "names": [
      "X",
      "x",
      "*"
    ]
  },
  "output": {
    "result": {
      "duplicates": [
        {
          "key": "x",
          "indexes": [
            0,
            1
          ]
        }
      ],
      "wildcard": true,
      "wildcardMixed": true
    }
  }
}

Limitations and assumptions

The input is an explicit name list, not a parsed Vary header or an automatically repaired policy.
No HTTP exchange, cache store, clock or server is accessed. Header/directive occurrences and timestamps are supplied explicitly. Durations use seconds for HTTP semantics; timestamps must share an origin and unit.
Every declared top-level input is required and unknown fields are rejected. Ordinary strings are limited to 8,192 UTF-16 code units and lists to 128 entries, with tighter operation-specific bounds where stated. JSON text has bounded nesting and node counts.
Numeric outputs must be finite and within the absolute safe-integer magnitude; exact larger integers use decimal text. Source positions are zero-based UTF-16 offsets and span ends are exclusive unless a different convention is explicitly stated.

Alternative or Complementary methods

Combine these focused results with the request/response caching rules applicable to the actual exchange. Preserve field occurrences and distinguish freshness calculations, validator comparison and complete cache-reuse authorization.

References

RFC 9111: HTTP Caching — RFC Editor
Tool behavior and example: Vary Name Set Audit — tool.io

Similar or alternative tools

Vary Request Value Fingerprint
Fingerprint explicit Vary request field occurrence arrays, distinguishing absent from empty fields and returning null for Vary star; reusable means no star only, not full cache reuse authorization.
Cache Corrected Initial Age
Compute RFC 9111 corrected initial cache age from explicit same-unit timestamps and Age value; no actual network observation or clock synchronization assumed.