70 lines
2 KiB
OCaml
70 lines
2 KiB
OCaml
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module Etag = struct
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(* https://httpwg.org/specs/rfc9110.html#field.etag *)
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type t = {
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weak: bool;
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value: string;
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}
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let pp ppf { weak; value } =
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match weak with
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| false -> Fmt.pf ppf {|"%s"|} value
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| true -> Fmt.pf ppf {|W/"%s"|} value
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let to_field_string t = Fmt.str "%a" pp t
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let angstrom =
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let open Angstrom in
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let is_valid_char c =
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let n = Char.code c in
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(n >= 0x21 && n <= 0x7E && n <> 0x22) || (n >= 0x80 && n <= 0xFF)
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in
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let quoted_string = char '"' *> take_while is_valid_char <* char '"' in
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lift2
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(fun weak value -> { weak; value })
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(option false (string "W/" *> return true))
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quoted_string
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let parse s =
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match Angstrom.parse_string ~consume:Angstrom.Consume.All angstrom s with
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| Error _e -> Fmt.error "invalid etag: `%s`" s
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| Ok v -> Ok v
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end
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module If_none_match = struct
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type t =
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| Any
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| List of Etag.t list
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let pp ppf = function
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| Any -> Fmt.pf ppf {|*|}
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| List l -> Fmt.pf ppf {|%a|} (Fmt.list ~sep:(Fmt.any ", ") Etag.pp) l
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let angstrom =
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let open Angstrom in
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let ows = skip_while (function ' ' | '\t' -> true | _ -> false) in
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let comma = ows *> char ',' *> ows in
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(* A recipient MUST parse and ignore a reasonable number of empty list elements *)
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let etag_opt = Etag.angstrom >>| Option.some <|> return None in
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let etags =
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etag_opt >>= fun hd ->
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many (comma *> etag_opt) >>= fun tl ->
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let l = List.filter_map Fun.id (hd :: tl) in
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match l with [] -> fail "empty etag list" | l -> return (List l)
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in
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let any = char '*' *> return Any in
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any <|> etags
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let parse s =
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match Angstrom.parse_string ~consume:Angstrom.Consume.All angstrom s with
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| Error _e -> Fmt.error "invalid if-none-match field: `%s`" s
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| Ok v -> Ok v
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let evaluate etag t =
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match t with
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| Any -> false
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| List l ->
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not
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@@ List.exists (fun e -> String.equal etag.Etag.value e.Etag.value) l
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end
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