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Merge pull request #121 from permaweb/tillathehun0/flat-http
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feat(hb_codec_httpsig_conv): flatten body to single depth, in lieu of nested multipart.
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@samcamwilliams
samcamwilliams authored Feb 6, 2025
2 parents 73f9159 + bdc8d76 commit 7685acc
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Showing 2 changed files with 57 additions and 57 deletions.
108 changes: 54 additions & 54 deletions src/dev_codec_httpsig_conv.erl
View file
Original file line number Diff line number Diff line change
Expand Up @@ -125,12 +125,12 @@ from_body(TABM, ContentType, Body) ->
% By taking into account all parts of the surrounding boundary above,
% we get precisely the sub-part that we're interested without any
% additional parsing
Parts = binary:split(BodyPart, [<<"--", Boundary/binary>>], [global]),
Parts = binary:split(BodyPart, [<<?CRLF/binary, "--", Boundary/binary>>], [global]),
% Finally, for each part within the sub-part, we need to parse it,
% potentially recursively as a sub-TABM, and then add it to the
% current TABM
{ok, NewTABM} = from_body_parts(TABM, Parts),
NewTABM
{ok, FlattendTABM} = from_body_parts(TABM, Parts),
dev_codec_flat:from(FlattendTABM)
end.

from_body_parts (TABM, []) -> {ok, TABM};
Expand Down Expand Up @@ -190,6 +190,10 @@ from_body_parts(TABM, [Part | Rest]) ->
% So simply use the the raw body binary as the part
RawBody;
_ ->
% TODO: this branch may no longer be needed
% since we flatten the maps prior to HTTP encoding
%
% For now, keeping recursive logic.
% We need to recursively parse the sub part into its own TABM
from(RestHeaders#{ <<"body">> => RawBody })
end,
Expand Down Expand Up @@ -273,29 +277,30 @@ attestations_from_signature(Map, HPs, RawSig, RawSigInput) ->
to(Bin) when is_binary(Bin) -> Bin;
to(TABM) -> to(TABM, []).
to(TABM, Opts) when is_map(TABM) ->
% PublicMsg = hb_private:reset(TABM)s
% MinimizedMsg = hb_message:minimize(PublicMsg),
% Calculate the initial encoding from the TABM
Enc0 =
maps:fold(
fun(<<"body">>, Value, AccMap) ->
fun
(<<"body">>, Value, AccMap) ->
AccMap#{ <<"body">> => #{ <<"body">> => Value } };
(Key, Value, AccMap) -> field_to_http(AccMap, {Key, Value}, #{})
(Key, Value, AccMap) ->
field_to_http(AccMap, {Key, Value}, #{})
end,
#{},
maps:without([<<"attestations">>, <<"signature">>, <<"signature-input">>], TABM)
),
?event({prepared_body_map, {msg, Enc0}}),
BodyMap = maps:get(<<"body">>, Enc0, #{}),
FlattenedBodyMap = hb_converge:normalize_keys(BodyMap),
Enc1 =
case {BodyMap, lists:member(sub_part, Opts)} of
case {FlattenedBodyMap, lists:member(sub_part, Opts)} of
{X, _} when map_size(X) =:= 0 ->
% If the body map is empty, then simply set the body to be a
% corresponding empty binary.
?event({encoding_empty_body, {msg, Enc0}}),
maps:put(<<"body">>, <<>>, Enc0);
{#{ <<"body">> := UserBody }, false}
when map_size(BodyMap) =:= 1 andalso is_binary(UserBody) ->
when map_size(FlattenedBodyMap) =:= 1 andalso is_binary(UserBody) ->
% Simply set the sole body binary as the body of the
% HTTP message, no further encoding required
%
Expand All @@ -311,27 +316,9 @@ to(TABM, Opts) when is_map(TABM) ->
_ ->
% Otherwise, we need to encode the body map as the
% multipart body of the HTTP message
?event({encoding_multipart, {bodymap, {explicit, BodyMap}}}),
% We need to generate a unique, reproducible boundary for the
% multipart body, however we cannot use the id of the message as
% the boundary, as the id is not known until the message is
% encoded. Subsequently, we generate each body part individually,
% concatenate them, and apply a SHA2-256 hash to the result.
% This ensures that the boundary is unique, reproducible, and
% secure.
ProcessedBodyParts = maps:map(fun encode_body_part/2, BodyMap),
PartList = to_sorted_list(ProcessedBodyParts),
BodyBin =
iolist_to_binary(
lists:join(?CRLF,
lists:map(
fun ({_PartName, PartBin}) -> PartBin end,
PartList
)
)
),
RawBoundary = crypto:hash(sha256, BodyBin),
Boundary = hb_util:encode(RawBoundary),
?event({encoding_multipart, {bodymap, {explicit, FlattenedBodyMap}}}),
PartList = to_sorted_list(maps:map(fun encode_body_part/2, FlattenedBodyMap)),
Boundary = boundary_from_parts(PartList),
% Transform body into a binary, delimiting each part with the
% boundary
BodyList = lists:foldl(
Expand Down Expand Up @@ -372,6 +359,26 @@ to(TABM, Opts) when is_map(TABM) ->
not_found -> Enc1
end.

% We need to generate a unique, reproducible boundary for the
% multipart body, however we cannot use the id of the message as
% the boundary, as the id is not known until the message is
% encoded. Subsequently, we generate each body part individually,
% concatenate them, and apply a SHA2-256 hash to the result.
% This ensures that the boundary is unique, reproducible, and
% secure.
boundary_from_parts(PartList) ->
BodyBin =
iolist_to_binary(
lists:join(?CRLF,
lists:map(
fun ({_PartName, PartBin}) -> PartBin end,
PartList
)
)
),
RawBoundary = crypto:hash(sha256, BodyBin),
hb_util:encode(RawBoundary).

%% Extract all hashpaths from the attestations of a given message
hashpaths_from_message(Msg) ->
maps:fold(
Expand Down Expand Up @@ -410,6 +417,10 @@ encode_body_part(PartName, BodyPart) ->
% satisfies that requirement, but also encodes the
% HB message field that resolves to the sub-message
case BodyPart of
% TODO: this branch may no longer be needed
% since we flatten the maps prior to HTTP encoding
%
% For now, keeping recursive logic
BPMap when is_map(BPMap) ->
WithDisposition = maps:put(
<<"content-disposition">>,
Expand All @@ -419,25 +430,15 @@ encode_body_part(PartName, BodyPart) ->
SubHttp = to(WithDisposition, [sub_part]),
encode_http_msg(SubHttp);
BPBin when is_binary(BPBin) ->
case PartName of
% A properly encoded inlined body part MUST have a CRLF between
% it and the header block, so we MUST use two CRLF:
% - first to signal end of the Content-Disposition header
% - second to signal the end of the header block
<<"body">> ->
<<
"content-disposition: ", Disposition/binary, ?CRLF/binary,
?CRLF/binary,
BPBin/binary
>>;
% All other binary values are encoded as a header in their
% respective sub-part
_ ->
<<
"content-disposition: ", Disposition/binary, ?CRLF/binary,
BPBin/binary
>>
end
% A properly encoded inlined body part MUST have a CRLF between
% it and the header block, so we MUST use two CRLF:
% - first to signal end of the Content-Disposition header
% - second to signal the end of the header block
<<
"content-disposition: ", Disposition/binary, ?CRLF/binary,
?CRLF/binary,
BPBin/binary
>>
end.

%%% @doc Given a map or KVList, return a sorted list of its key-value pairs.
Expand Down Expand Up @@ -500,11 +501,10 @@ field_to_http(Httpsig, {Name, Value}, Opts) when is_binary(Value) ->
%
% Note that a "where" Opts may force the location of the encoded
% value -- this is only a default location if not specified in Opts
DefaultWhere =
case {maps:get(where, Opts, headers), byte_size(Value)} of
{headers, Fits} when Fits =< ?MAX_HEADER_LENGTH -> headers;
_ -> body
end,
DefaultWhere = case {maps:get(where, Opts, headers), byte_size(Value)} of
{headers, Fits} when Fits =< ?MAX_HEADER_LENGTH -> headers;
_ -> body
end,
case maps:get(where, Opts, DefaultWhere) of
headers ->
Httpsig#{ NormalizedName => Value };
Expand Down
6 changes: 3 additions & 3 deletions src/dev_wasi.erl
View file
Original file line number Diff line number Diff line change
Expand Up @@ -22,15 +22,15 @@

-define(INIT_FDS,
#{
0 => #{
<<"0">> => #{
<<"filename">> => <<"/dev/stdin">>,
<<"offset">> => 0
},
1 => #{
<<"1">> => #{
<<"filename">> => <<"/dev/stdout">>,
<<"offset">> => 0
},
2 => #{
<<"2">> => #{
<<"filename">> => <<"/dev/stderr">>,
<<"offset">> => 0
}
Expand Down

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