文件下载器

apps/efka/src/efka_downloader.erl

@@ -12,15 +12,14 @@
 -behaviour(gen_server).
 
 %% API
--export([start_link/2, download/1]).
+-export([start_link/0, download/3]).
 -export([test/0]).
 
 %% gen_server callbacks
 -export([init/1, handle_call/3, handle_cast/2, handle_info/2, terminate/2, code_change/3]).
 
 -record(state, {
-    url :: string(),
-    target_file :: string()
+
 }).
 
 %%%===================================================================
@@ -28,26 +27,28 @@
 %%%===================================================================
 
 test() ->
-    {ok, Pid} = start_link("https://codeload.github.com/genadyo/LivePhotoDemo/zip/refs/heads/master", "/tmp/master.tar"),
-    Ref = download(Pid),
+    {ok, Pid} = start_link(),
+    Url = "https://codeload.github.com/genadyo/LivePhotoDemo/zip/refs/heads/master",
+    TargetDir = "/tmp/",
+    Ref = download(Pid, Url, TargetDir),
     receive
         {download_response, Ref, Info} ->
             lager:debug("info is: ~p", [Info])
     end,
     ok.
 
--spec download(Pid :: pid()) -> reference().
-download(Pid) when is_pid(Pid) ->
+-spec download(Pid :: pid(), Url :: string(), TargetDir :: string()) -> reference().
+download(Pid, Url, TargetDir) when is_pid(Pid), is_list(Url), is_list(TargetDir) ->
     Ref = make_ref(),
     ReceiverPid = self(),
-    gen_server:cast(Pid, {download, ReceiverPid, Ref}),
+    gen_server:cast(Pid, {download, ReceiverPid, Ref, Url, TargetDir}),
     Ref.
 
 %% @doc Spawns the server and registers the local name (unique)
--spec(start_link(Url :: string(), TargetFile :: string()) ->
+-spec(start_link() ->
     {ok, Pid :: pid()} | ignore | {error, Reason :: term()}).
-start_link(Url, TargetFile) when is_list(Url), is_list(TargetFile) ->
-    gen_server:start_link(?MODULE, [Url, TargetFile], []).
+start_link() ->
+    gen_server:start_link(?MODULE, [], []).
 
 %%%===================================================================
 %%% gen_server callbacks
@@ -58,8 +59,8 @@ start_link(Url, TargetFile) when is_list(Url), is_list(TargetFile) ->
 -spec(init(Args :: term()) ->
     {ok, State :: #state{}} | {ok, State :: #state{}, timeout() | hibernate} |
     {stop, Reason :: term()} | ignore).
-init([Url, TargetFile]) ->
-    {ok, #state{url = Url, target_file = TargetFile}}.
+init([]) ->
+    {ok, #state{}}.
 
 %% @private
 %% @doc Handling call messages
@@ -80,15 +81,16 @@ handle_call(_Request, _From, State = #state{}) ->
     {noreply, NewState :: #state{}} |
     {noreply, NewState :: #state{}, timeout() | hibernate} |
     {stop, Reason :: term(), NewState :: #state{}}).
-handle_cast({download, ReceiverPid, Ref}, State = #state{url = Url, target_file = TargetFile}) ->
+handle_cast({download, ReceiverPid, Ref, Url, TargetDir}, State = #state{}) ->
     SSLOpts = {ssl_options, [
         % 完全禁用证书验证
         {verify, verify_none}
     ]},
 
-    case hackney:request(get, Url, [], <<>>, [async, {pool, false}, SSLOpts]) of
+    TargetFile = get_filename_from_url(Url),
+    case hackney:request(get, Url, [], <<>>, [async, {stream_to, self()}, {pool, false}, SSLOpts]) of
         {ok, ClientRef} ->
-            case receive_data(ClientRef, TargetFile) of
+            case receive_data(ClientRef, TargetDir, TargetFile) of
                 ok ->
                     ReceiverPid ! {download_response, Ref, ok};
                 {error, Reason} ->
@@ -130,57 +132,56 @@ code_change(_OldVsn, State = #state{}, _Extra) ->
 %%% Internal functions
 %%%===================================================================
 
-receive_data(ClientRef, DefaultFile) ->
+%% 读取请求 ResponseLine
+receive_data(ClientRef, TargetDir, DefaultFile) when is_list(TargetDir), is_list(DefaultFile) ->
     receive
         {hackney_response, ClientRef, {status, 200, _Reason}} ->
-            lager:debug("22"),
-            receive_data0(ClientRef, DefaultFile);
+            receive_data0(ClientRef, TargetDir, DefaultFile);
         {hackney_response, ClientRef, {status, StatusCode, _Reason}} ->
             {error, {http_status, StatusCode}}
     end.
-receive_data0(ClientRef, DefaultFile) ->
+%% 处理头部信息, 解析可能的文件名
+receive_data0(ClientRef, TargetDir, DefaultFile) ->
     receive
         {hackney_response, ClientRef, {headers, Headers}} ->
-            lager:debug("11 data bytes: ~p", [extra_filename(Headers)]),
-            TargetFile = case extra_filename(Headers) of
-                             error ->
-                                 DefaultFile;
-                             {ok, Filename} ->
-                                 Filename
-                         end,
-            {ok, File} = file:open(TargetFile, [write, binary]),
+            TargetFilename = extra_filename(Headers, DefaultFile),
+            FullFilename = TargetDir ++ TargetFilename,
+            {ok, File} = file:open(FullFilename, [write, binary]),
             receive_data1(ClientRef, File)
     end.
+%% 接受文件数据
 receive_data1(ClientRef, File) ->
     receive
         {hackney_response, ClientRef, {error, Reason}} ->
-            lager:debug("error11"),
             ok = file:close(File),
             {error, Reason};
         {hackney_response, ClientRef, done} ->
-            lager:debug("error22"),
             ok = file:close(File),
             hackney:close(ClientRef),
             ok;
         {hackney_response, ClientRef, Data} ->
-            lager:debug("data: ~p", [byte_size(Data)]),
             file:write(File, Data),
             receive_data1(ClientRef, File)
     end.
 
--spec extra_filename(Headers :: list()) -> error | {ok, Filename :: string()}.
-extra_filename(Headers) when is_list(Headers) ->
+-spec extra_filename(Headers :: list(), Default :: string()) -> Filename :: string().
+extra_filename(Headers, Default) when is_list(Headers), is_list(Default) ->
     case lists:filter(fun({K, _}) -> string:lowercase(K) =:= <<"content-disposition">> end, Headers) of
         [{_, <<"attachment; ", Rest/binary>>}|_] ->
             Params0 = binary:split(Rest, <<";">>, [global]),
             Params = lists:map(fun(P) -> list_to_tuple(binary:split(P, <<"=">>)) end, Params0),
-            filename(Params);
+            case proplists:get_value(<<"filename">>, Params) of
+                undefined ->
+                    Default;
+                Filename ->
+                    binary_to_list(Filename)
+            end;
         _ ->
-            error
+            Default
     end.
-filename([]) ->
-    error;
-filename([{<<"filename">>, Filename}|_]) ->
-    {ok, binary_to_list(Filename)};
-filename([_|Tail]) ->
-    filename(Tail).
+
+-spec get_filename_from_url(Url :: string()) -> string().
+get_filename_from_url(Url) when is_list(Url) ->
+    URIMap = uri_string:parse(Url),
+    Path = maps:get(path, URIMap),
+    filename:basename(Path).