diff options
Diffstat (limited to 'src/cowboy_http_static.erl')
| -rw-r--r-- | src/cowboy_http_static.erl | 34 |
1 files changed, 17 insertions, 17 deletions
diff --git a/src/cowboy_http_static.erl b/src/cowboy_http_static.erl index 0ee996a..007cd16 100644 --- a/src/cowboy_http_static.erl +++ b/src/cowboy_http_static.erl @@ -96,15 +96,16 @@ %% %% The default behaviour can be overridden to generate an ETag header based on %% a combination of the file path, file size, inode and mtime values. If the -%% option value is a list of attribute names tagged with `attributes' a hex -%% encoded CRC32 checksum of the attribute values are used as the ETag header -%% value. +%% option value is a non-empty list of attribute names tagged with `attributes' +%% a hex encoded checksum of each attribute specified is included in the value +%% of the the ETag header. If the list of attribute names is empty no ETag +%% header is generated. %% %% If a strong ETag is required a user defined function for generating the %% header value can be supplied. The function must accept a proplist of the %% file attributes as the first argument and a second argument containing any -%% additional data that the function requires. The function must return a -%% `binary()' or `undefined'. +%% additional data that the function requires. The function must return a term +%% of the type `{weak | strong, binary()}' or `undefined'. %% %% ==== Examples ==== %% ``` @@ -130,7 +131,7 @@ %% {_, _Modified} = lists:keyfind(mtime, 1, Arguments), %% ChecksumCommand = lists:flatten(io_lib:format("sha1sum ~s", [Filepath])), %% [Checksum|_] = string:tokens(os:cmd(ChecksumCommand), " "), -%% iolist_to_binary(Checksum). +%% {strong, iolist_to_binary(Checksum)}. %% ''' -module(cowboy_http_static). @@ -161,7 +162,8 @@ filepath :: binary() | error, fileinfo :: {ok, #file_info{}} | {error, _} | error, mimetypes :: {fun((binary(), T) -> [mimedef()]), T} | undefined, - etag_fun :: {fun(([etagarg()], T) -> undefined | binary()), T}}). + etag_fun :: {fun(([etagarg()], T) -> + undefined | {strong | weak, binary()}), T}}). %% @private Upgrade from HTTP handler to REST handler. @@ -183,8 +185,9 @@ rest_init(Req, Opts) -> ETagFunction = case proplists:get_value(etag, Opts) of default -> {fun no_etag_function/2, undefined}; undefined -> {fun no_etag_function/2, undefined}; + {attributes, []} -> {fun no_etag_function/2, undefined}; {attributes, Attrs} -> {fun attr_etag_function/2, Attrs}; - {_, _}=EtagFunction1 -> EtagFunction1 + {_, _}=ETagFunction1 -> ETagFunction1 end, {Filepath, Req1} = cowboy_http_req:path_info(Req), State = case check_path(Filepath) of @@ -411,16 +414,13 @@ no_etag_function(_Args, undefined) -> %% @private A simple alternative is to send an ETag based on file attributes. -type fileattr() :: filepath | filesize | mtime | inode. --spec attr_etag_function([etagarg()], [fileattr()]) -> binary(). +-spec attr_etag_function([etagarg()], [fileattr()]) -> {strong, binary()}. attr_etag_function(Args, Attrs) -> - attr_etag_function(Args, Attrs, []). - --spec attr_etag_function([etagarg()], [fileattr()], [binary()]) -> binary(). -attr_etag_function(_Args, [], Acc) -> - list_to_binary(integer_to_list(erlang:crc32(Acc), 16)); -attr_etag_function(Args, [H|T], Acc) -> - {_, Value} = lists:keyfind(H, 1, Args), - attr_etag_function(Args, T, [term_to_binary(Value)|Acc]). + [[_|H]|T] = [begin + {_,Pair} = {_,{_,_}} = {Attr,lists:keyfind(Attr, 1, Args)}, + [$-|integer_to_list(erlang:phash2(Pair, 1 bsl 32), 16)] + end || Attr <- Attrs], + {strong, list_to_binary([H|T])}. -ifdef(TEST). |