Parse HTTP header

Parse HTTP header lines into normalized names, raw values, and repeated fields.

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ToolHTTP Header Parser
Input
Output
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How it works

Lines split at the first colon, field names normalize case-insensitively, obsolete folding is handled or rejected, and comma-list fields can be tokenized. Duplicate fields stay distinct unless their field rules allow combination.

  • Case-insensitivity applies to names, not arbitrary values.
  • Raw preservation avoids lossy parsing.

Worked example

Parse three common response headers
Parse Content-Type, Cache-Control, and X-Request-Id into structured JSON
Input
											Content-Type: application/json
Cache-Control: no-cache
X-Request-Id: abc-123
Output
												Name           Value
-------------  ----------------
Content-Type   application/json
Cache-Control  no-cache
X-Request-Id   abc-123

When to use this

Proxy logs, API debugging, and security reviews parse headers.

Edge cases

  • A comma inside quotes is not necessarily a list separator.
  • Set-Cookie fields must not be joined like ordinary lists.
  • HTTP optional whitespace is not every Unicode whitespace character.

References