feat: adds a service to interrupt a request (#2)

Author: TENSIILE

src/packages/index.ts

@@ -0,0 +1,74 @@
+import { Request, Response, NextFunction } from 'express';
+
+type AbortFunction = () => void;
+
+export const getRequestId = (req: Request): string => {
+  const requestId = req.headers['x-request-id']?.toString().split(',');
+  return requestId?.[0] ?? '';
+};
+
+export class AbortableService {
+  private abortRegistries = new Map<string, AbortFunction | null>();
+
+  private registerAbortableFunction = (
+    requestId: string,
+    abortFn: AbortFunction
+  ): void => {
+    this.abortRegistries.set(requestId, abortFn);
+  };
+
+  public abort = (
+    requestId: string,
+    { deletable = true }: { deletable?: boolean } = {}
+  ): boolean => {
+    const abortFn = this.abortRegistries.get(requestId) ?? null;
+
+    if (abortFn) {
+      abortFn();
+
+      if (deletable) {
+        this.abortRegistries.delete(requestId);
+      }
+
+      return true;
+    }
+
+    return false;
+  };
+
+  public expressMiddleware = (
+    req: Request,
+    res: Response,
+    next: NextFunction
+  ) => {
+    const requestId = getRequestId(req);
+
+    console.log('MIDDLEWARE', this.abortRegistries);
+
+    if (!requestId) {
+      return next();
+    }
+
+    if (this.abortRegistries.has(requestId)) {
+      this.abort(requestId, { deletable: false });
+    }
+
+    const controller = new AbortController();
+
+    (req as any).controller = controller;
+    (req as any).signal = controller.signal;
+
+    this.registerAbortableFunction(requestId, () => {
+      controller.abort(new Error('AbortError'));
+    });
+
+    req.on('close', () => {
+      if (!res.writableEnded) {
+        console.log('requestId', requestId);
+        this.abort(requestId);
+      }
+    });
+
+    next();
+  };
+}

src/service/abortable-service.ts

@@ -0,0 +1 @@
+export * from './abortable-service';