JSON-RPC: retrieve events via long polling

This way is more compatible to JSON-RPC libraries
that do not support receiving notifications from the server
and allows describing event types in the OpenRPC specification.

Event thread converting events to notifications in the FFI
is removed, so it is now possible to construct a dc_jsonrpc_instance_t
while still retrieving events via dc_event_emitter_t.

deltachat-jsonrpc/src/webserver.rs

@@ -6,7 +6,6 @@ use yerpc::axum::handle_ws_rpc;
 use yerpc::{RpcClient, RpcSession};
 
 mod api;
-use api::events::event_to_json_rpc_notification;
 use api::{Accounts, CommandApi};
 
 const DEFAULT_PORT: u16 = 20808;
@@ -44,12 +43,5 @@ async fn main() -> Result<(), std::io::Error> {
 async fn handler(ws: WebSocketUpgrade, Extension(api): Extension<CommandApi>) -> Response {
     let (client, out_receiver) = RpcClient::new();
     let session = RpcSession::new(client.clone(), api.clone());
-    tokio::spawn(async move {
-        let events = api.accounts.read().await.get_event_emitter();
-        while let Some(event) = events.recv().await {
-            let event = event_to_json_rpc_notification(event);
-            client.send_notification("event", Some(event)).await.ok();
-        }
-    });
     handle_ws_rpc(ws, out_receiver, session).await
 }