[couchdb] branch changes-websocket updated (1f9a761a7 -> b18a9ef3b)

[rn...@apache.org]

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rnewson pushed a change to branch changes-websocket
in repository https://gitbox.apache.org/repos/asf/couchdb.git


 discard 1f9a761a7 support Websocket protocol for continuous response
     new b18a9ef3b support Websocket protocol for continuous response

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Summary of changes:
 src/chttpd/src/chttpd_db.erl | 19 +++++++++++++++++--
 1 file changed, 17 insertions(+), 2 deletions(-)

[couchdb] 01/01: support Websocket protocol for continuous response

[rn...@apache.org]

This is an automated email from the ASF dual-hosted git repository.

rnewson pushed a commit to branch changes-websocket
in repository https://gitbox.apache.org/repos/asf/couchdb.git

commit b18a9ef3b383eb89af863d1cdb5baec2d981e632
Author: Robert Newson <rn...@apache.org>
AuthorDate: Mon Jun 26 21:29:08 2023 +0100

    support Websocket protocol for continuous response
    
    needs mochiweb tweak;
    
    diff --git a/src/mochiweb_websocket.erl b/src/mochiweb_websocket.erl
    index 22ef924..044a18e 100644
    --- a/src/mochiweb_websocket.erl
    +++ b/src/mochiweb_websocket.erl
    @@ -74,6 +74,12 @@ call_body({M, F}, Payload, State, ReplyChannel) ->
     call_body(Body, Payload, State, ReplyChannel) ->
         Body(Payload, State, ReplyChannel).
    
    +send(Socket, pong, hybi) ->
    +    mochiweb_socket:send(Socket, <<1:1, 0:3, 10:4, 0:8>>);
    +send(Socket, {close, Code}, hybi) when Code >= 1000, Code =< 1015 ->
    +    mochiweb_socket:send(Socket, <<1:1, 0:3, 8:4, 2:8, Code:16>>),
    +    mochiweb_socket:close(Socket),
    +    exit({shutdown, websocket_close});
     send(Socket, Payload, hybi) ->
         Prefix = <<1:1, 0:3, 1:4,
                   (payload_length(iolist_size(Payload)))/binary>>,
---
 src/chttpd/src/chttpd_db.erl | 42 ++++++++++++++++++++++++++++++++++--------
 1 file changed, 34 insertions(+), 8 deletions(-)

diff --git a/src/chttpd/src/chttpd_db.erl b/src/chttpd/src/chttpd_db.erl
index 791ee86f3..18808d13a 100644
--- a/src/chttpd/src/chttpd_db.erl
+++ b/src/chttpd/src/chttpd_db.erl
@@ -163,26 +163,38 @@ handle_changes_req1(#httpd{} = Req, Db) ->
             throw({bad_request, Msg})
     end.
 
-% websocket goop
+% websocket callbacks
 changes_callback(start, #cacc{feed = continuous, websocket = true} = Acc) ->
     {ReentryWs, ReplyChannel} = mochiweb_websocket:upgrade_connection(
-        Acc#cacc.mochi, fun client_ws_loop/3),
-    {ok, Acc#cacc{mochi = undefined, websocket = {ws, ReentryWs, ReplyChannel}}};
+        Acc#cacc.mochi#httpd.mochi_req, fun client_ws_loop/3),
+    {ok, Acc#cacc{websocket = {ws, ReentryWs, ReplyChannel}}};
 changes_callback({change, Change}, #cacc{websocket = {ws, _ReentryWs, ReplyChannel}} = Acc) ->
     chttpd_stats:incr_rows(),
     ReplyChannel(?JSON_ENCODE(Change)),
     {ok, Acc};
 changes_callback(timeout, #cacc{websocket = {ws, _ReentryWs, ReplyChannel}} = Acc) ->
-    ReplyChannel("\n"),
+    ReplyChannel(pong),
     {ok, Acc};
-changes_callback({stop, EndSeq, Pending}, #cacc{websocket = {ws, _ReentryWs, ReplyChannel}} = Acc) ->
+changes_callback(waiting_for_updates, #cacc{websocket = {ws, _ReentryWs, _ReplyChannel}} = Acc) ->
+    check_ws_client_error(Acc#cacc.mochi#httpd.mochi_req),
+    {ok, Acc};
+changes_callback({error, Reason}, #cacc{websocket = {ws, _ReentryWs, ReplyChannel}} = _Acc) ->
+    {_Code, ErrorStr, ReasonStr} = chttpd:error_info(Reason),
+    Row =
+        {[
+            {<<"error">>, ErrorStr},
+            {<<"reason">>, ReasonStr}
+         ]},
+    ReplyChannel(?JSON_ENCODE(Row)),
+    ReplyChannel({close, 1011});
+changes_callback({stop, EndSeq, Pending}, #cacc{websocket = {ws, _ReentryWs, ReplyChannel}} = _Acc) ->
     Row =
         {[
             {<<"last_seq">>, EndSeq},
             {<<"pending">>, Pending}
         ]},
     ReplyChannel(?JSON_ENCODE(Row)),
-    {stop, Acc};
+    ReplyChannel({close, 1000});
 
 % callbacks for continuous feed (newline-delimited JSON Objects)
 changes_callback(start, #cacc{feed = continuous} = Acc) ->
@@ -2584,8 +2596,22 @@ websocket_upgrade_requested(#httpd{} = Req) ->
     Upgrade = chttpd:header_value(Req, "Upgrade"),
     Upgrade =/= undefined andalso string:to_lower(Upgrade) =:= "websocket".
 
-client_ws_loop(_Payload, Broadcaster, _ReplyChannel) ->
-    Broadcaster.
+client_ws_loop(_Payload, State, _ReplyChannel) ->
+    State.
+
+check_ws_client_error(Req) ->
+    {ReqM, _} = Req,
+    Socket = ReqM:get(socket, Req),
+    receive
+        {tcp_closed = Error, _} ->
+            mochiweb_socket:close(Socket), exit({shutdown, Error});
+        {ssl_closed = Error, _} ->
+            mochiweb_socket:close(Socket), exit({shutdown, Error});
+        {tcp_error, _, Error} ->
+            mochiweb_socket:close(Socket), exit({shutdown, {tcp_error, Error}})
+    after 0 ->
+            ok
+    end.
 
 -ifdef(TEST).
 -include_lib("eunit/include/eunit.hrl").