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-rw-r--r--examples/rest_stream_response/src/toppage_handler.erl42
1 files changed, 42 insertions, 0 deletions
diff --git a/examples/rest_stream_response/src/toppage_handler.erl b/examples/rest_stream_response/src/toppage_handler.erl
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+++ b/examples/rest_stream_response/src/toppage_handler.erl
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+%% Feel free to use, reuse and abuse the code in this file.
+
+%% @doc Streaming handler.
+-module(toppage_handler).
+
+-export([init/3]).
+-export([rest_init/2]).
+-export([content_types_provided/2]).
+-export([streaming_csv/2]).
+
+init(_Transport, _Req, _Table) ->
+ {upgrade, protocol, cowboy_rest}.
+
+rest_init(Req, Table) ->
+ {ok, Req, Table}.
+
+content_types_provided(Req, State) ->
+ {[
+ {{<<"text">>, <<"csv">>, []}, streaming_csv}
+ ], Req, State}.
+
+streaming_csv(Req, Table) ->
+ {N, Req1} = cowboy_req:binding(v1, Req, 1),
+ MS = [{{'$1', '$2', '$3'}, [{'==', '$2', N}], ['$$']}],
+
+ {{stream, result_streamer(Table, MS)}, Req1, Table}.
+
+result_streamer(Table, MS) ->
+ fun (Socket, Transport) ->
+ send_records(Socket, Transport, ets:select(Table, MS, 1))
+ end.
+
+send_records(Socket, Transport, {[Rec], Cont}) ->
+ timer:sleep(500),
+ send_line(Socket, Transport, Rec),
+ send_records(Socket, Transport, ets:select(Cont));
+send_records(_Socket, _Transport, '$end_of_table') ->
+ ok.
+
+send_line(Socket, Transport, [Key, V1, V2]) ->
+ Transport:send(Socket,
+ [Key, $,, integer_to_list(V1), $,, integer_to_list(V2), $\r, $\n]).