Header_name

HTTP header name enumeration for efficient header processing

The Header_name module provides an enumeration of common HTTP headers for efficient header name comparison and processing. Unknown headers are represented as Other with the actual name stored in the header’s name_span field.

Type Definition

t · variant

HTTP header name enumeration.

Cache_control · variant

Cache-Control header

Connection · variant

Connection header

Date · variant

Date header

Transfer_encoding · variant

Transfer-Encoding header

Upgrade · variant

Upgrade header

Via · variant

Via header

Accept · variant

Accept header

Accept_charset · variant

Accept-Charset header

Accept_encoding · variant

Accept-Encoding header

Accept_language · variant

Accept-Language header

Accept_ranges · variant

Accept-Ranges header

Authorization · variant

Authorization header

Cookie · variant

Cookie header

Expect · variant

Expect header

Host · variant

Host header

If_match · variant

If-Match header

If_modified_since · variant

If-Modified-Since header

If_none_match · variant

If-None-Match header

If_range · variant

If-Range header

If_unmodified_since · variant

If-Unmodified-Since header

Range · variant

Range header

Referer · variant

Referer header

User_agent · variant

User-Agent header

Age · variant

Age header

Etag · variant

ETag header

Location · variant

Location header

Retry_after · variant

Retry-After header

Server · variant

Server header

Set_cookie · variant

Set-Cookie header

Www_authenticate · variant

WWW-Authenticate header

Allow · variant

Allow header

Content_disposition · variant

Content-Disposition header

Content_encoding · variant

Content-Encoding header

Content_language · variant

Content-Language header

Content_length · variant

Content-Length header

Content_location · variant

Content-Location header

Content_range · variant

Content-Range header

Content_type · variant

Content-Type header

Expires · variant

Expires header

Last_modified · variant

Last-Modified header

X_forwarded_for · variant

X-Forwarded-For header

X_forwarded_proto · variant

X-Forwarded-Proto header

X_forwarded_host · variant

X-Forwarded-Host header

X_request_id · variant

X-Request-Id header

X_correlation_id · variant

X-Correlation-Id header

Other · variant

Unknown header; the actual name is stored in the header’s name_span field

Parsing

of_span

val of_span : local_ Base_bigstring.t -> Span.t -> t

Parse header name from span. Returns a known header variant if recognized, otherwise Other.

buf · local_ Base_bigstring.t · required

The buffer containing the header name

span · Span.t · required

The span representing the header name in the buffer

Example:

let name = Header_name.of_span buffer header.name_span in
match name with
| Content_type -> (* Handle Content-Type *)
  ...
| Host -> (* Handle Host *)
  ...
| Other -> (* Handle unknown header *)
  let name_str = Span.to_string buffer header.name_span in
  ...

Conversion Functions

canonical

val canonical : t -> string

Canonical display name for known headers. Returns "(unknown)" for Other.

Use this for response writing when you don’t need buffer access.

header_name · t · required

The header name to convert

Example:

let display_name = Header_name.canonical Content_type in
(* Returns: "Content-Type" *)

let unknown = Header_name.canonical Other in
(* Returns: "(unknown)" *)

to_string

val to_string : local_ Base_bigstring.t -> t -> string

Deprecated: Use canonical instead - the buffer parameter is unused.

Canonical display name for headers. Returns "(unknown)" for Other.

buf · local_ Base_bigstring.t · required

Buffer parameter (unused)

header_name · t · required

The header name to convert

lowercase

val lowercase : t -> string

Lowercase canonical name for known headers. Returns "" for Other.

header_name · t · required

The header name to convert

Example:

let lower = Header_name.lowercase Content_type in
(* Returns: "content-type" *)

let unknown = Header_name.lowercase Other in
(* Returns: "" *)

Pretty Printing

pp

val pp : Stdlib.Format.formatter -> t -> unit

Pretty-print header name.

formatter · Stdlib.Format.formatter · required

The formatter to print to

header_name · t · required

The header name to print

Example:

Format.printf "Header: %a@." Header_name.pp Content_type
(* Output: Header: Content-Type *)

Usage Examples

Processing Headers by Type

let process_header buffer header =
  let name = Header_name.of_span buffer header.name_span in
  match name with
  | Content_length ->
    let length = Span.parse_int64 buffer header.value_span in
    (* Handle content length *)
    ...
  | Content_type ->
    let mime = Span.to_string buffer header.value_span in
    (* Handle content type *)
    ...
  | Host ->
    (* Handle host header *)
    ...
  | Other ->
    (* Handle custom headers *)
    let name = Span.to_string buffer header.name_span in
    let value = Span.to_string buffer header.value_span in
    ...

Writing Response Headers

let write_header name value =
  let canonical_name = Header_name.canonical name in
  Printf.sprintf "%s: %s\r\n" canonical_name value