make evaljs_value threadsafe

js_dependencies/JSServe.bundled.js

@@ -3957,6 +3957,7 @@ const mod1 = {
     OBJECT_FREEING_LOCK: OBJECT_FREEING_LOCK,
     lock_loading: lock_loading,
     lookup_global_object: lookup_global_object,
+    free_object: free_object,
     track_deleted_sessions: track_deleted_sessions,
     done_initializing_session: done_initializing_session,
     init_session: init_session,
@@ -4026,7 +4027,7 @@ function onany(observables, f) {
 }
 const { send_error: send_error1 , send_warning: send_warning1 , process_message: process_message1 , on_connection_open: on_connection_open1 , on_connection_close: on_connection_close1 , send_close_session: send_close_session1 , send_pingpong: send_pingpong1 , can_send_to_julia: can_send_to_julia1  } = mod;
 const { base64decode: base64decode1 , base64encode: base64encode1 , decode_binary: decode_binary1 , encode_binary: encode_binary1 , decode_base64_message: decode_base64_message1  } = mod2;
-const { init_session: init_session1 , free_session: free_session1 , lookup_global_object: lookup_global_object1 , update_or_replace: update_or_replace1 , lock_loading: lock_loading1 , OBJECT_FREEING_LOCK: OBJECT_FREEING_LOCK1  } = mod1;
+const { init_session: init_session1 , free_session: free_session1 , lookup_global_object: lookup_global_object1 , update_or_replace: update_or_replace1 , lock_loading: lock_loading1 , OBJECT_FREEING_LOCK: OBJECT_FREEING_LOCK1 , free_object: free_object1  } = mod1;
 function update_node_attribute(node, attribute, value) {
     if (node) {
         if (node[attribute] != value) {
@@ -4079,8 +4080,9 @@ const JSServe = {
     update_or_replace: update_or_replace1,
     OBJECT_FREEING_LOCK: OBJECT_FREEING_LOCK1,
     can_send_to_julia: can_send_to_julia1,
-    onany
+    onany,
+    free_object: free_object1
 };
 window.JSServe = JSServe;
-export { mod2 as Protocol, base64decode1 as base64decode, base64encode1 as base64encode, decode_binary1 as decode_binary, encode_binary1 as encode_binary, decode_base64_message1 as decode_base64_message, mod as Connection, send_error1 as send_error, send_warning1 as send_warning, process_message1 as process_message, on_connection_open1 as on_connection_open, on_connection_close1 as on_connection_close, send_close_session1 as send_close_session, send_pingpong1 as send_pingpong, mod1 as Sessions, init_session1 as init_session, free_session1 as free_session, lock_loading1 as lock_loading, update_node_attribute as update_node_attribute, update_dom_node as update_dom_node, lookup_global_object1 as lookup_global_object, update_or_replace1 as update_or_replace, onany as onany, OBJECT_FREEING_LOCK1 as OBJECT_FREEING_LOCK, can_send_to_julia1 as can_send_to_julia };
+export { mod2 as Protocol, base64decode1 as base64decode, base64encode1 as base64encode, decode_binary1 as decode_binary, encode_binary1 as encode_binary, decode_base64_message1 as decode_base64_message, mod as Connection, send_error1 as send_error, send_warning1 as send_warning, process_message1 as process_message, on_connection_open1 as on_connection_open, on_connection_close1 as on_connection_close, send_close_session1 as send_close_session, send_pingpong1 as send_pingpong, mod1 as Sessions, init_session1 as init_session, free_session1 as free_session, lock_loading1 as lock_loading, update_node_attribute as update_node_attribute, update_dom_node as update_dom_node, lookup_global_object1 as lookup_global_object, update_or_replace1 as update_or_replace, onany as onany, OBJECT_FREEING_LOCK1 as OBJECT_FREEING_LOCK, can_send_to_julia1 as can_send_to_julia, free_object1 as free_object };
 

js_dependencies/JSServe.js

@@ -29,6 +29,7 @@ const {
     update_or_replace,
     lock_loading,
     OBJECT_FREEING_LOCK,
+    free_object,
 } = Sessions;
 
 function update_node_attribute(node, attribute, value) {
@@ -92,7 +93,8 @@ const JSServe = {
     update_or_replace,
     OBJECT_FREEING_LOCK,
     can_send_to_julia,
-    onany
+    onany,
+    free_object,
 };
 
 // @ts-ignore
@@ -126,4 +128,5 @@ export {
     onany,
     OBJECT_FREEING_LOCK,
     can_send_to_julia,
+    free_object,
 };

js_dependencies/Sessions.js

@@ -50,7 +50,7 @@ function is_still_referenced(id) {
     return false;
 }
 
-function free_object(id) {
+export function free_object(id) {
     const data = GLOBAL_OBJECT_CACHE[id];
     if (data) {
         if (data instanceof Promise) {

src/connection/websocket.jl

@@ -93,7 +93,10 @@ function run_connection_loop(server::Server, session::Session, connection::WebSo
             bytes = save_read(websocket)
             # nothing means the browser closed the connection so we're done
             isnothing(bytes) && break
-            try
+            # Needs to be async to not block websocket read loop if events
+            # messages being processed are blocking, which happens
+            # Easily with on(some_longer_processing, obs)
+            @async try
                 process_message(session, bytes)
             catch e
                 # Only print any internal error to not close the connection

src/session.jl

@@ -247,28 +247,41 @@ function evaljs_value(session::Session, js; error_on_closed=true, timeout=10.0)
         It may unblock, if the browser is still connecting and opening the session later on. If this is expected,
         you may try setting `error_on_closed=false`")
     end
-    comm = root.js_comm
-    comm[] = nothing
-    js_with_result = js"""
-    try{
-        const maybe_promise = $(js);
-        // support returning a promise:
-        Promise.resolve(maybe_promise).then(result=> {
-            $(comm).notify({result});
-        })
-    }catch(e){
-        $(comm).notify({error: e.toString()});
+    # For each request we need a new observable to have this thread safe
+    # And multiple request not waiting on the same observable
+    comm = Observable{Any}(nothing)
+    js_with_result = js"""{
+        const comm = $(comm);
+        try{
+            const maybe_promise = $(js);
+            // support returning a promise:
+            Promise.resolve(maybe_promise).then(result=> {
+                comm.notify({result});
+            })
+        }catch(e){
+            comm.notify({error: e.toString()});
+        } finally {
+            // manually free!!
+            JSServe.free_object(comm.id);
+        }
     }
     """
-
     evaljs(session, js_with_result)
     # TODO, have an on error callback, that triggers when evaljs goes wrong
     # (e.g. because of syntax error that isn't caught by the above try catch!)
     # TODO do this with channels, but we still dont have a way to timeout for wait(channel)... so...
-    wait_for(()-> !isnothing(comm[]); timeout=timeout)
-    value = comm[]
+    value = nothing
+    # Nothing should be deleted while we wait!
+    lock(root.deletion_lock) do
+        wait_for(timeout=timeout) do
+            return !isnothing(comm[])
+        end
+        value = comm[]
+        # manually free observable, since it exists outside session lifetimes
+        delete!(session.session_objects, comm.id)
+        delete!(root.session_objects, comm.id)
+    end
     Observables.clear(comm) # cleanup
-    comm[] = nothing
     if isnothing(value)
         error("Timed out")
     end

src/types.jl

@@ -239,13 +239,14 @@ end
 function Session(parent_session::Session;
     asset_server=similar(parent_session.asset_server),
     on_connection_ready=init_session, title=parent_session.title)
-
     root = root_session(parent_session)
-    connection = SubConnection(root)
-    session = Session(connection; asset_server=asset_server, on_connection_ready=on_connection_ready, title=title)
-    session.parent = parent_session
-    parent_session.children[session.id] = session
-    return session
+    return lock(root.deletion_lock) do
+        connection = SubConnection(root)
+        session = Session(connection; asset_server=asset_server, on_connection_ready=on_connection_ready, title=title)
+        session.parent = parent_session
+        parent_session.children[session.id] = session
+        return session
+    end
 end
 
 mutable struct App

test/subsessions.jl

@@ -125,23 +125,18 @@ edisplay = JSServe.use_electron_display(devtools=true)
 
 end
 
-@testset "js comm" begin
+@testset "cleanup comm" begin
     app = App() do s
         return DOM.div()
     end
     display(edisplay, app)
     @test !isnothing(app.session[])
     @test isready(app.session[])
-    @test evaljs_value(app.session[], js"Object.keys(JSServe.Sessions.SESSIONS).length") == 2
+    @test run(edisplay.window, "Object.keys(JSServe.Sessions.SESSIONS).length") == 2
     root = JSServe.root_session(app.session[])
     @test root !== app.session[]
-    @test evaljs_value(app.session[], js"Object.keys(JSServe.Sessions.GLOBAL_OBJECT_CACHE).length") == 1
-    @test evaljs_value(app.session[], js"Object.keys(JSServe.Sessions.GLOBAL_OBJECT_CACHE)[0]") == root.js_comm.id
-    @test length(root.session_objects) == 1
-    @test haskey(root.session_objects, root.js_comm.id)
+    @test run(edisplay.window, "Object.keys(JSServe.Sessions.GLOBAL_OBJECT_CACHE).length") == 0
+    @test isempty(root.session_objects)
     close(app.session[])
-    @test evaljs_value(root, js"Object.keys(JSServe.Sessions.GLOBAL_OBJECT_CACHE).length") == 1
-    @test evaljs_value(root, js"Object.keys(JSServe.Sessions.GLOBAL_OBJECT_CACHE)[0]") == root.js_comm.id
-    @test evaljs_value(root, js"Object.keys(JSServe.Sessions.SESSIONS).length") == 1
-    @test isempty(root.js_comm.listeners)
+    @test run(edisplay.window, "Object.keys(JSServe.Sessions.SESSIONS).length") == 1
 end