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Diffstat (limited to 'src/mochiweb/mochiweb_headers.erl')
-rw-r--r-- | src/mochiweb/mochiweb_headers.erl | 178 |
1 files changed, 178 insertions, 0 deletions
diff --git a/src/mochiweb/mochiweb_headers.erl b/src/mochiweb/mochiweb_headers.erl new file mode 100644 index 00000000..5b538aa7 --- /dev/null +++ b/src/mochiweb/mochiweb_headers.erl @@ -0,0 +1,178 @@ +%% @author Bob Ippolito <bob@mochimedia.com> +%% @copyright 2007 Mochi Media, Inc. + +%% @doc Case preserving (but case insensitive) HTTP Header dictionary. + +-module(mochiweb_headers). +-author('bob@mochimedia.com'). +-export([empty/0, from_list/1, insert/3, enter/3, get_value/2, lookup/2]). +-export([get_primary_value/2]). +-export([default/3, enter_from_list/2, default_from_list/2]). +-export([to_list/1, make/1]). +-export([test/0]). + +%% @type headers(). +%% @type key() = atom() | binary() | string(). +%% @type value() = atom() | binary() | string() | integer(). + +%% @spec test() -> ok +%% @doc Run tests for this module. +test() -> + H = ?MODULE:make([{hdr, foo}, {"Hdr", "bar"}, {'Hdr', 2}]), + [{hdr, "foo, bar, 2"}] = ?MODULE:to_list(H), + H1 = ?MODULE:insert(taco, grande, H), + [{hdr, "foo, bar, 2"}, {taco, "grande"}] = ?MODULE:to_list(H1), + H2 = ?MODULE:make([{"Set-Cookie", "foo"}]), + [{"Set-Cookie", "foo"}] = ?MODULE:to_list(H2), + H3 = ?MODULE:insert("Set-Cookie", "bar", H2), + [{"Set-Cookie", "foo"}, {"Set-Cookie", "bar"}] = ?MODULE:to_list(H3), + "foo, bar" = ?MODULE:get_value("set-cookie", H3), + {value, {"Set-Cookie", "foo, bar"}} = ?MODULE:lookup("set-cookie", H3), + undefined = ?MODULE:get_value("shibby", H3), + none = ?MODULE:lookup("shibby", H3), + H4 = ?MODULE:insert("content-type", + "application/x-www-form-urlencoded; charset=utf8", + H3), + "application/x-www-form-urlencoded" = ?MODULE:get_primary_value( + "content-type", H4), + ok. + +%% @spec empty() -> headers() +%% @doc Create an empty headers structure. +empty() -> + gb_trees:empty(). + +%% @spec make(headers() | [{key(), value()}]) -> headers() +%% @doc Construct a headers() from the given list. +make(L) when is_list(L) -> + from_list(L); +%% assume a tuple is already mochiweb_headers. +make(T) when is_tuple(T) -> + T. + +%% @spec from_list([{key(), value()}]) -> headers() +%% @doc Construct a headers() from the given list. +from_list(List) -> + lists:foldl(fun ({K, V}, T) -> insert(K, V, T) end, empty(), List). + +%% @spec enter_from_list([{key(), value()}], headers()) -> headers() +%% @doc Insert pairs into the headers, replace any values for existing keys. +enter_from_list(List, T) -> + lists:foldl(fun ({K, V}, T1) -> enter(K, V, T1) end, T, List). + +%% @spec default_from_list([{key(), value()}], headers()) -> headers() +%% @doc Insert pairs into the headers for keys that do not already exist. +default_from_list(List, T) -> + lists:foldl(fun ({K, V}, T1) -> default(K, V, T1) end, T, List). + +%% @spec to_list(headers()) -> [{key(), string()}] +%% @doc Return the contents of the headers. The keys will be the exact key +%% that was first inserted (e.g. may be an atom or binary, case is +%% preserved). +to_list(T) -> + F = fun ({K, {array, L}}, Acc) -> + L1 = lists:reverse(L), + lists:foldl(fun (V, Acc1) -> [{K, V} | Acc1] end, Acc, L1); + (Pair, Acc) -> + [Pair | Acc] + end, + lists:reverse(lists:foldl(F, [], gb_trees:values(T))). + +%% @spec get_value(key(), headers()) -> string() | undefined +%% @doc Return the value of the given header using a case insensitive search. +%% undefined will be returned for keys that are not present. +get_value(K, T) -> + case lookup(K, T) of + {value, {_, V}} -> + expand(V); + none -> + undefined + end. + +%% @spec get_primary_value(key(), headers()) -> string() | undefined +%% @doc Return the value of the given header up to the first semicolon using +%% a case insensitive search. undefined will be returned for keys +%% that are not present. +get_primary_value(K, T) -> + case get_value(K, T) of + undefined -> + undefined; + V -> + lists:takewhile(fun (C) -> C =/= $; end, V) + end. + +%% @spec lookup(key(), headers()) -> {value, {key(), string()}} | none +%% @doc Return the case preserved key and value for the given header using +%% a case insensitive search. none will be returned for keys that are +%% not present. +lookup(K, T) -> + case gb_trees:lookup(normalize(K), T) of + {value, {K0, V}} -> + {value, {K0, expand(V)}}; + none -> + none + end. + +%% @spec default(key(), value(), headers()) -> headers() +%% @doc Insert the pair into the headers if it does not already exist. +default(K, V, T) -> + K1 = normalize(K), + V1 = any_to_list(V), + try gb_trees:insert(K1, {K, V1}, T) + catch + error:{key_exists, _} -> + T + end. + +%% @spec enter(key(), value(), headers()) -> headers() +%% @doc Insert the pair into the headers, replacing any pre-existing key. +enter(K, V, T) -> + K1 = normalize(K), + V1 = any_to_list(V), + gb_trees:enter(K1, {K, V1}, T). + +%% @spec insert(key(), value(), headers()) -> headers() +%% @doc Insert the pair into the headers, merging with any pre-existing key. +%% A merge is done with Value = V0 ++ ", " ++ V1. +insert(K, V, T) -> + K1 = normalize(K), + V1 = any_to_list(V), + try gb_trees:insert(K1, {K, V1}, T) + catch + error:{key_exists, _} -> + {K0, V0} = gb_trees:get(K1, T), + V2 = merge(K1, V1, V0), + gb_trees:update(K1, {K0, V2}, T) + end. + +%% Internal API + +expand({array, L}) -> + mochiweb_util:join(lists:reverse(L), ", "); +expand(V) -> + V. + +merge("set-cookie", V1, {array, L}) -> + {array, [V1 | L]}; +merge("set-cookie", V1, V0) -> + {array, [V1, V0]}; +merge(_, V1, V0) -> + V0 ++ ", " ++ V1. + +normalize(K) when is_list(K) -> + string:to_lower(K); +normalize(K) when is_atom(K) -> + normalize(atom_to_list(K)); +normalize(K) when is_binary(K) -> + normalize(binary_to_list(K)). + +any_to_list(V) when is_list(V) -> + V; +any_to_list(V) when is_atom(V) -> + atom_to_list(V); +any_to_list(V) when is_binary(V) -> + binary_to_list(V); +any_to_list(V) when is_integer(V) -> + integer_to_list(V). + + |