chore: rename fundamentals to base (#9119)

packages/backend/server/src/base/cache/interceptor.ts

@@ -0,0 +1,99 @@
+import {
+  CallHandler,
+  ExecutionContext,
+  Injectable,
+  Logger,
+  NestInterceptor,
+  SetMetadata,
+} from '@nestjs/common';
+import { Reflector } from '@nestjs/core';
+import { GqlContextType, GqlExecutionContext } from '@nestjs/graphql';
+import { mergeMap, Observable, of } from 'rxjs';
+
+import { Cache } from './instances';
+
+export const MakeCache = (key: string[], args?: string[]) =>
+  SetMetadata('cacheKey', [key, args]);
+export const PreventCache = (key: string[], args?: string[]) =>
+  SetMetadata('preventCache', [key, args]);
+
+type CacheConfig = [string[], string[]?];
+
+@Injectable()
+export class CacheInterceptor implements NestInterceptor {
+  private readonly logger = new Logger(CacheInterceptor.name);
+  constructor(
+    private readonly reflector: Reflector,
+    private readonly cache: Cache
+  ) {}
+  async intercept(
+    ctx: ExecutionContext,
+    next: CallHandler<any>
+  ): Promise<Observable<any>> {
+    const key = this.reflector.get<CacheConfig | undefined>(
+      'cacheKey',
+      ctx.getHandler()
+    );
+    const preventKey = this.reflector.get<CacheConfig | undefined>(
+      'preventCache',
+      ctx.getHandler()
+    );
+
+    if (preventKey) {
+      const key = await this.getCacheKey(ctx, preventKey);
+      if (key) {
+        this.logger.verbose(`cache ${key} staled`);
+        await this.cache.delete(key);
+      }
+
+      return next.handle();
+    } else if (!key) {
+      return next.handle();
+    }
+
+    const cacheKey = await this.getCacheKey(ctx, key);
+
+    if (!cacheKey) {
+      return next.handle();
+    }
+
+    const cachedData = await this.cache.get(cacheKey);
+
+    if (cachedData) {
+      this.logger.verbose(`cache ${cacheKey} hit`);
+      return of(cachedData);
+    } else {
+      this.logger.verbose(`cache ${cacheKey} miss`);
+      return next.handle().pipe(
+        mergeMap(async result => {
+          await this.cache.set(cacheKey, result);
+
+          return result;
+        })
+      );
+    }
+  }
+
+  private async getCacheKey(
+    ctx: ExecutionContext,
+    config: CacheConfig
+  ): Promise<string | null> {
+    const [key, params] = config;
+
+    if (!params) {
+      return key.join(':');
+    } else if (ctx.getType<GqlContextType>() === 'graphql') {
+      const args = GqlExecutionContext.create(ctx).getArgs();
+      const cacheKey = params
+        .map(name => args[name])
+        .filter(v => v)
+        .join(':');
+      if (cacheKey) {
+        return [...key, cacheKey].join(':');
+      } else {
+        return key.join(':');
+      }
+    }
+    return null;
+  }
+}