Fix multiple sockets opening without closing

src/cp/index.ts

@@ -54,22 +54,23 @@ export default class ChargePoint {
     private readonly csUrl: string
   ) { }
 
-  async connect(): Promise<void> {
+  async connect(): Promise<Connection<CentralSystemAction<'v1.6-json'>>> {
     const url = `${this.csUrl}/${this.id}`;
     const socket = new WebSocket(url, SUPPORTED_PROTOCOLS);
 
-    this.connection = new Connection(
+    const connection = new Connection(
       socket,
       this.requestHandler,
       centralSystemActions,
       chargePointActions,
     );
+    this.connection = connection;
     // this.socket.on('close', () => (this.socket = undefined));
     socket.on('error', console.error);
-    socket.on('message', (data) => this.connection?.handleWebsocketData(data));
+    socket.on('message', (data) => connection?.handleWebsocketData(data));
 
     return new Promise((resolve) => {
-      socket?.on('open', () => resolve());
+      socket?.on('open', () => resolve(connection));
     });
   }
 

src/cs/index.ts

@@ -88,7 +88,13 @@ type RequiredPick<T, K extends keyof T> = Omit<T, K> & Required<Pick<T, K>>
  */
 export default class CentralSystem {
   private cpHandler: RequestHandler<ChargePointAction, RequestMetadata>;
-  private connections: Record<string, Connection<ChargePointAction>> = {};
+  /** each chargepoint has a list of connections because there is an
+   * issue with some chargers that do not fully close the previous websocket connection
+   * after creating a new websocket connection, with this we can still keep track of all
+   * current opened sockets, and only remove the connections whose sockets have closed.
+   *
+   * (for more info: see the test "if two sockets open before the first one closing, should still remain the latest socket") */
+  private connections: Record<string, Array<Connection<ChargePointAction>>> = {};
   private listeners: ConnectionListener[] = [];
   private websocketsServer: WebSocket.Server;
   private soapServer: soap.Server;
@@ -137,7 +143,8 @@ export default class CentralSystem {
 
       switch (args.ocppVersion) {
         case 'v1.6-json': {
-          const connection = this.connections[args.chargePointId];
+          // get the first available connection of this chargepoint
+          const [connection] = this.connections[args.chargePointId] ?? [];
           if (!connection) return Left(new OCPPRequestError('there is no connection to this charge point'));
 
           return connection
@@ -187,9 +194,6 @@ export default class CentralSystem {
     const normalizeHeaders = (headers: Record<string, string>) =>
       Object.entries(headers).reduce<Record<string, string>>((acc, [key, val]) => (acc[key.toLowerCase()] = val, acc), {});
 
-    server.addSoapHeader((action: any, args: any, headers: Record<string, string>) => ({
-      chargeBoxIdentity: normalizeHeaders(headers).chargeboxidentity
-    }), '', 'ocpp', 'urn://Ocpp/Cs/2012/06/');
     server.addSoapHeader((action: any, args: any, headers: any) => ({
       'Action': '/' + action + 'Response',
       'MessageID': uuid.v4(),
@@ -256,14 +260,19 @@ export default class CentralSystem {
       centralSystemActions,
       this.options.rejectInvalidRequests,
     );
-    this.connections[chargePointId] = connection;
+
+    if (!this.connections[chargePointId]) {
+      this.connections[chargePointId] = [];
+    }
+    this.connections[chargePointId].push(connection);
 
     socket.on('message', (data) => {
       this.options.onRawWebsocketData?.(data, metadata);
       connection.handleWebsocketData(data)
     });
     socket.on('close', () => {
-      delete this.connections[chargePointId];
+      const closedIndex = this.connections[chargePointId].findIndex(c => c === connection);
+      this.connections[chargePointId].splice(closedIndex, 1);
       clearInterval(pingInterval);
       this.listeners.forEach((f) => f(chargePointId, 'disconnected'));
     });

src/integration.spec.ts

@@ -106,4 +106,72 @@ describe('test cs<->cp communication', () => {
 
     afterAll(() => cs.close());
   });
+
+  it('if two sockets open before the first one closing, should still remain the latest socket', async () => {
+    const PORT = 8082;
+    const cs = new CentralSystem(PORT, (_req, _cpId) => {
+      throw new Error('cs');
+    });
+
+    const cp = new ChargePoint(
+      '123',
+      req => {
+        switch (req.action) {
+          case 'GetConfiguration': return {
+            action: req.action,
+            ocppVersion: req.ocppVersion,
+            configurationKey: []
+          }
+          default: throw new Error('unsupported')
+        }
+      },
+      `ws://localhost:${PORT}`
+    );
+
+    let triggerConnected = (_cpId: string) => { };
+    let triggerDisconnected = (_cpId: string) => { };
+    cs.addConnectionListener((cpId, status) => {
+      if (status === 'connected') triggerConnected(cpId);
+      if (status === 'disconnected') triggerDisconnected(cpId);
+    });
+    const waitForConnection = (cpId: string) =>
+      new Promise((resolve) => {
+        triggerConnected = (connectedId) => {
+          if (connectedId == cpId) resolve(cpId);
+        };
+      });
+
+    const waitForDisconnection = (cpId: string) =>
+      new Promise((resolve) => {
+        triggerDisconnected = (connectedId) => {
+          if (connectedId == cpId) resolve(cpId);
+        };
+      });
+
+    // connecting once
+    let waitCentralSystem = waitForConnection(cp.id);
+    const firstConnection = await cp.connect();
+    await waitCentralSystem;
+
+    // connecting twice
+    waitCentralSystem = waitForConnection(cp.id);
+    const secondConnection = await cp.connect();
+    await waitCentralSystem;
+
+    waitCentralSystem = waitForDisconnection(cp.id);
+    firstConnection.close();
+    await waitCentralSystem;
+
+    // should send request to the second connection
+    (await cs.sendRequest({
+      action: 'GetConfiguration',
+      ocppVersion: 'v1.6-json',
+      chargePointId: cp.id,
+      payload: {}
+    })).unsafeCoerce();
+
+    // cleanup
+    cp.close();
+    cs.close()
+  })
 });

src/ws/connection.ts

@@ -11,7 +11,7 @@ import { EitherAsync, Left, Right, Just, Nothing, MaybeAsync } from 'purify-ts';
 export default class Connection<ReqAction extends ActionName<'v1.6-json'>> {
   private messageTriggers: Record<string, (m: OCPPJMessage) => void> = {};
   constructor(
-    private readonly socket: WebSocket,
+    public readonly socket: WebSocket,
     private readonly requestHandler: RequestHandler<ReqAction, ValidationError | undefined, 'v1.6-json'>,
     private readonly requestedActions: ReqAction[],
     private readonly respondedActions: ActionName<'v1.6-json'>[],