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