sandbox/pe/filesrv/fserve.erl

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2019-04-24 22:46:05 +00:00
-module(fserve).
-export([start/0, file_serve/2, put/2, get/1]).
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-include("./msg.hrl").
start () ->
spawn(fserve, file_serve, [#{}, sets:new()]).
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file_serve(Names, DataStore) ->
receive
#upload{client=Client, data=Data} ->
case upload(DataStore, Data) of
{ok, UpdatedDataStore, CAS_ID} ->
Client ! CAS_ID,
file_serve(Names, UpdatedDataStore);
{error, Reason} -> throw(Reason)
end;
#stop{client=Client} ->
io:format("Shutdown message received from ~w~n", [Client]);
#dump{client=Client} ->
io:format("Dumping store.~n"),
Client ! {Names, DataStore},
file_serve(Names, DataStore)
end.
put(DataStore, Data) ->
<<HashBinary:256/big-unsigned-integer>> = crypto:hash(sha256, Data),
Hash = integer_to_list(HashBinary, 16),
case sets:is_element(Hash, DataStore) of
false ->
Path = "data/" ++ Hash,
case file:write_file(Path, Data) of
ok ->
io:format("Wrote ~s to file ~s~n", [Hash, Path]),
{ok, sets:add_element(Hash, DataStore), Hash};
{error, Reason} -> {error, Reason}
end;
true ->
io:format("Receive request to store previously stored ~s~n", [Hash]),
{ok, DataStore, Hash}
end.
get(ID) ->
Path = "data/" ++ ID,
file:read_file(Path).
upload(DataStore, Data) ->
case fserve:put(DataStore, Data) of
{ok, UpdatedDataStore, ID} ->
io:format("Successfully stored file.~n"),
{ok, UpdatedDataStore, ID};
{error, Reason} -> {error, Reason}
end.