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nestjs学习(四)
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Guards
确定请求是否应由路由处理程序处理,在每个中间件之后执行,但在任何pipe之前执行。
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Authorization guard
import { Injectable, CanActivate, ExecutionContext } from '@nestjs/common'; import { Observable } from 'rxjs'; @Injectable() export class AuthGuard implements CanActivate { canActivate( context: ExecutionContext, ): boolean | Promise<boolean> | Observable<boolean> { const request = context.switchToHttp().getRequest(); return validateRequest(request); } }
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Role-based authentication
import { Injectable, CanActivate, ExecutionContext } from '@nestjs/common'; import { Observable } from 'rxjs'; @Injectable() export class RolesGuard implements CanActivate { canActivate( context: ExecutionContext, ): boolean | Promise<boolean> | Observable<boolean> { return true; } } // 绑定 @Controller('cats') @UseGuards(RolesGuard) export class CatsController {} // 全局 绑定 app.useGlobalGuards(new RolesGuard()); // 模块绑定 import { Module } from '@nestjs/common'; import { APP_GUARD } from '@nestjs/core'; @Module({ providers: [ { provide: APP_GUARD, useClass: RolesGuard, }, ], }) export class ApplicationModule {}
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Reflector
@Post() @ReflectMetadata('roles', ['admin']) //使用ReflectMetadata装饰器 async create(@Body() createCatDto: CreateCatDto) { this.catsService.create(createCatDto); } // 直接使用不太好, 建立自己的decorator // roles.decorator.ts import { ReflectMetadata } from '@nestjs/common'; export const Roles = (...roles: string[]) => ReflectMetadata('roles', roles); // 这样就可以直接使用 @Roles('admin') // roles.guard.ts 示例 import { Injectable, CanActivate, ExecutionContext } from '@nestjs/common'; import { Observable } from 'rxjs'; import { Reflector } from '@nestjs/core'; @Injectable() export class RolesGuard implements CanActivate { constructor(private readonly reflector: Reflector) {} canActivate(context: ExecutionContext): boolean { const roles = this.reflector.get<string[]>('roles', context.getHandler()); if (!roles) { return true; } const request = context.switchToHttp().getRequest(); const user = request.user; const hasRole = () => user.roles.some((role) => roles.includes(role)); return user && user.roles && hasRole(); } }
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Interceptors 拦截器
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功能
- 在方法执行之前/之后绑定额外的逻辑
- 转换函数返回的结果
- 转换从函数抛出的异常
- 扩展基本函数行为
- 根据所选条件完全覆盖函数(例如缓存目的)
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拦截示例
import { Injectable, NestInterceptor, ExecutionContext } from '@nestjs/common'; import { Observable } from 'rxjs'; import { tap, map } from 'rxjs/operators'; @Injectable() export class LoggingInterceptor implements NestInterceptor { intercept( context: ExecutionContext, call$: Observable<any>, ): Observable<any> { console.log('Before...'); const now = Date.now(); return call$.pipe( tap(() => console.log(`After... ${Date.now() - now}ms`)), ); // return call$.pipe(map(data => ({ data }))); 返回一个map } } // 类绑定,方法绑定,全局绑定useGlobalInterceptors() @UseInterceptors(LoggingInterceptor) // 模块绑定 import { Module } from '@nestjs/common'; import { APP_INTERCEPTOR } from '@nestjs/core'; @Module({ providers: [ { provide: APP_INTERCEPTOR, useClass: LoggingInterceptor, }, ], }) export class ApplicationModule {}
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自定义路由装饰器
// 自定义装饰器 import { createParamDecorator } from '@nestjs/common'; export const User = createParamDecorator((data, req) => { return req.user; }); // data 可以接收string, 也可以接受pipe @Get() async findOne(@User(new ValidationPipe()) user: UserEntity) { console.log(user); }