Create GraphQLHttpWebSocket throw NotSupportedException in WASM

[albiberto]

I tryed to use GraphQLClient in Blazor WASM project.
During client instating was throw an exception.
By reading the code I see this problem in System.Reactive.Concurrency.EventLoopScheduler.
The problem is the ThreadFactory in the library becouse it try to create a new thread.

This is the stack trace:

crit: Microsoft.AspNetCore.Components.WebAssembly.Rendering.WebAssemblyRenderer[100]
Unhandled exception rendering component: Cannot start threads on this runtime.
System.NotSupportedException: Cannot start threads on this runtime.
at (wrapper managed-to-native) System.Threading.Thread.Thread_internal(System.Threading.Thread,System.MulticastDelegate)
at System.Threading.Thread.StartInternal (System.Object principal, System.Threading.StackCrawlMark& stackMark) <0x31c6738 + 0x00008> in :0
at System.Threading.Thread.Start (System.Threading.StackCrawlMark& stackMark) <0x31c6630 + 0x0004c> in :0
at System.Threading.Thread.Start () <0x31c6570 + 0x0000e> in :0
at System.Reactive.Concurrency.EventLoopScheduler.EnsureThread () <0x31c5178 + 0x00036> in :0
at System.Reactive.Concurrency.EventLoopScheduler.Schedule[TState] (TState state, System.TimeSpan dueTime, System.Func3[T1,T2,TResult] action) <0x31bad40 + 0x0014e> in <filename unknown>:0 at System.Reactive.Concurrency.LocalScheduler.Schedule[TState] (TState state, System.Func3[T1,T2,TResult] action) <0x31b4ed8 + 0x0002e> in :0
at System.Reactive.Concurrency.Scheduler.Schedule (System.Reactive.Concurrency.IScheduler scheduler, System.Action action) <0x31b4c98 + 0x00060> in :0
at GraphQL.Client.Http.Websocket.GraphQLHttpWebSocket..ctor (System.Uri webSocketUri, GraphQL.Client.Http.GraphQLHttpClient client) <0x30b07d8 + 0x0013c> in :0
at GraphQL.Client.Http.GraphQLHttpClient..ctor (GraphQL.Client.Http.GraphQLHttpClientOptions options, GraphQL.Client.Abstractions.Websocket.IGraphQLWebsocketJsonSerializer serializer, System.Net.Http.HttpClient httpClient) <0x3062218 + 0x00140> in :0
at GraphQL.Client.Http.GraphQLHttpClient..ctor (GraphQL.Client.Http.GraphQLHttpClientOptions options, GraphQL.Client.Abstractions.Websocket.IGraphQLWebsocketJsonSerializer serializer) <0x3053fd8 + 0x0001e> in :0
at GraphQL.Client.Http.GraphQLHttpClient..ctor (System.Action`1[T] configure, GraphQL.Client.Abstractions.Websocket.IGraphQLWebsocketJsonSerializer serializer) <0x303e600 + 0x00010> in :0
at GraphQL.Client.Http.GraphQLHttpClient..ctor (System.Uri endPoint, GraphQL.Client.Abstractions.Websocket.IGraphQLWebsocketJsonSerializer serializer) <0x303e420 + 0x00030> in :0
at GraphQL.Client.Http.GraphQLHttpClient..ctor (System.String endPoint, GraphQL.Client.Abstractions.Websocket.IGraphQLWebsocketJsonSerializer serializer) <0x303e088 + 0x00012> in :0
at Angy.BackEndClient.Pages.IndexComponent.OnInitializedAsync () <0x3024408 + 0x00034> in :0
at Microsoft.AspNetCore.Components.ComponentBase.RunInitAndSetParametersAsync () <0x2f3ba28 + 0x00154> in :0

To solve the problem could it be a good idea change the EventLoopScheduler whit a custom implementation, since it is hosted in third-party library?

Thanks Alberto

[rose-a]

Are you planning to use subscriptions in your application?

If not, PR #252 will solve this for you.

If you need subscriptions, it's unfortunately not that easy, replacing the EventLoopScheduler with something else potentially has lots of unforeseen side effects...

But thanks for bringing the single-threaded nature of WASM to my attention...

[bjorg]

Just ran into this issue as well.

[rose-a]

The EventLoopScheduler has been eliminated in v3.1.5, unsupported properties in v3.1.7.

I'm closing this in favour of #262