throttler

Once the installation is complete, the ThrottlerModule can be configured as any other Nest package with forRoot or forRootAsync methods.

@@filename(app.module)
@Module({
  imports: [
    ThrottlerModule.forRoot([{
      ttl: 60000,
      limit: 10,
    }]),
  ],
})
export class AppModule {}

The above will set the global options for the ttl, the time to live in milliseconds, and the limit, the maximum number of requests within the ttl, for the routes of your application that are guarded.

Once the module has been imported, you can then choose how you would like to bind the ThrottlerGuard. Any kind of binding as mentioned in the guards section is fine. If you wanted to bind the guard globally, for example, you could do so by adding this provider to any module:

{
  provide: APP_GUARD,
  useClass: ThrottlerGuard
}

Multiple Throttler Definitions

There may come upon times where you want to set up multiple throttling definitions, like no more than 3 calls in a second, 20 calls in 10 seconds, and 100 calls in a minute. To do so, you can set up your definitions in the array with named options, that can later be referenced in the @SkipThrottle() and @Throttle() decorators to change the options again.

@@filename(app.module)
@Module({
  imports: [
    ThrottlerModule.forRoot([
      {
        name: 'short',
        ttl: 1000,
        limit: 3,
      },
      {
        name: 'medium',
        ttl: 10000,
        limit: 20
      },
      {
        name: 'long',
        ttl: 60000,
        limit: 100
      }
    ]),
  ],
})
export class AppModule {}

Important note on using decorators with Named Throttlers:

When you have configured named throttlers (e.g., 'short', 'medium', 'long' as shown above), both the @SkipThrottle() and @Throttle() decorators must be provided with an object where keys are the names of your throttlers.

If you use @SkipThrottle() without specifying the names, it will not skip any of your named throttlers. Similarly, @Throttle() without specifying names cannot override settings for specific named throttlers.

Correct usage with named throttlers:

To skip specific named throttlers:

@SkipThrottle({ short: true, medium: true })
@Controller('users')
export class UsersController {}

To override limits for specific named throttlers:

@Throttle({ short: { limit: 5, ttl: 1000 }, medium: { limit: 30, ttl: 10000 } })
@Get()
findAll() {
  return "Custom limits for specific throttlers";
}

Incorrect usage (will not work as intended for named throttlers):

@SkipThrottle() // This will NOT skip any named throttlers
@Controller('users')
export class UsersController {}

For more details on this behavior, especially if migrating from older versions, please refer to the Migration to v5 guide.

Customization

There may be a time where you want to bind the guard to a controller or globally, but want to disable rate limiting for one or more of your endpoints. For that, you can use the @SkipThrottle() decorator to negate the throttler for an entire class or a single route.

The @SkipThrottle() decorator behaves differently based on your ThrottlerModule configuration:

1. For a single, default (unnamed) throttler: You can use @SkipThrottle(), @SkipThrottle(true), or @SkipThrottle({ default: true }).

@SkipThrottle()
@Controller('users')
export class UsersController {}

2. For multiple named throttlers (e.g., 'short', 'medium'): You must provide an object where keys are the names of the throttlers you wish to skip, and values are true.

@SkipThrottle({ short: true, medium: true })
@Controller('users')
export class UsersController {}

Important: Simply using @SkipThrottle() without an object will not skip any named throttlers. See the Multiple Throttler Definitions section for a detailed example and explanation.

The @SkipThrottle() decorator can also be used to negate the skipping of a route in a class that is already skipped:

@SkipThrottle({ default: true })
@Controller('users')
export class UsersController {
  // Rate limiting is applied to this route.
  @SkipThrottle({ default: false })
  dontSkip() {
    return 'List users work with Rate limiting.';
  }
  // This route will skip rate limiting.
  doSkip() {
    return 'List users work without Rate limiting.';
  }
}

There is also the @Throttle() decorator which can be used to override the limit and ttl set in the global module, to give tighter or looser security options. This decorator can be used on a class or a function as well. With version 5 and onwards, the decorator takes in an object with the string relating to the name of the throttler set, and an object with the limit and ttl keys and integer values, similar to the options passed to the root module. If you do not have a name set in your original options, use the string default You have to configure it like this:

// Override default configuration for Rate limiting and duration.
@Throttle({ default: { limit: 3, ttl: 60000 } })
@Get()
findAll() {
  return "List users works with custom rate limiting.";
}

Proxies

If your application runs behind a proxy server, check the specific HTTP adapter options (express and fastify) for the trust proxy option and enable it. Doing so will allow you to get the original IP address from the X-Forwarded-For header.

For express, no further configuration is needed because express sets req.ip to the client IP if trust proxy is enabled. For fastify, you need to read the client IP from req.ips instead. The following example is only needed for fastify, but works with both engines:

// throttler-behind-proxy.guard.ts
import { ThrottlerGuard } from '@nestjs/throttler';
import { Injectable } from '@nestjs/common';

@Injectable()
export class ThrottlerBehindProxyGuard extends ThrottlerGuard {
  protected getTracker(req: Record<string, any>): Promise<string> {
    // The client IP is the leftmost IP in req.ips. You can individualize IP
    // extraction to meet your own needs.
    const tracker = req.ips.length > 0 ? req.ips[0] : req.ip;
    return Promise.resolve(tracker);
  }
}

// app.controller.ts
import { ThrottlerBehindProxyGuard } from './throttler-behind-proxy.guard';

@UseGuards(ThrottlerBehindProxyGuard)

Hint: You can find the API of the req Request object for express here and for fastify here.

Websockets

This module can work with websockets, but it requires some class extension. You can extend the ThrottlerGuard and override the handleRequest method like so:

@Injectable()
export class WsThrottlerGuard extends ThrottlerGuard {
  async handleRequest(requestProps: ThrottlerRequest): Promise<boolean> {
    const { context, limit, ttl, throttler, blockDuration, generateKey } = requestProps;

    const client = context.switchToWs().getClient();
    const tracker = client._socket.remoteAddress;
    const key = generateKey(context, tracker, throttler.name);
    const { totalHits, timeToExpire, isBlocked, timeToBlockExpire } =
      await this.storageService.increment(key, ttl, limit, blockDuration, throttler.name);

    // Throw an error when the user reached their limit.
    if (isBlocked) {
      await this.throwThrottlingException(context, {
        limit,
        ttl,
        key,
        tracker,
        totalHits,
        timeToExpire,
        isBlocked,
        timeToBlockExpire,
      });
    }

    return true;
  }
}

Hint: If you are using ws, it is necessary to replace the _socket with conn.

There's a few things to keep in mind when working with WebSockets:

• Guard cannot be registered with the APP_GUARD or app.useGlobalGuards()
• When a limit is reached, Nest will emit an exception event, so make sure there is a listener ready for this

Hint: If you are using the @nestjs/platform-ws package you can use client._socket.remoteAddress instead.

GraphQL

The ThrottlerGuard can also be used to work with GraphQL requests. Again, the guard can be extended, but this time the getRequestResponse method will be overridden:

@Injectable()
export class GqlThrottlerGuard extends ThrottlerGuard {
  getRequestResponse(context: ExecutionContext) {
    const gqlCtx = GqlExecutionContext.create(context);
    const ctx = gqlCtx.getContext();
    return { req: ctx.req, res: ctx.res };
  }
}

However, when using Apollo Express/Fastify or Mercurius, it's important to configure the context correctly in the GraphQLModule to avoid any problems.

Apollo Server (for Express):

For Apollo Server running on Express, you can set up the context in your GraphQLModule configuration as follows:

GraphQLModule.forRoot({
  // ... other GraphQL module options
  context: ({ req, res }) => ({ req, res }),
});

Apollo Server (for Fastify) & Mercurius:

When using Apollo Server with Fastify or Mercurius, you need to configure the context differently. You should use request and reply objects. Here's an example:

GraphQLModule.forRoot({
  // ... other GraphQL module options
  context: (request, reply) => ({ request, reply }),
});

Configuration

The following options are valid for the object passed to the array of the ThrottlerModule's options:

If you need to set up storages instead, or want to use a some of the above options in a more global sense, applying to each throttler set, you can pass the options above via the throttlers option key and use the below table

Async Configuration

You may want to get your rate-limiting configuration asynchronously instead of synchronously. You can use the forRootAsync() method, which allows for dependency injection and async methods.

One approach would be to use a factory function:

@Module({
  imports: [
    ThrottlerModule.forRootAsync({
      imports: [ConfigModule],
      inject: [ConfigService],
      useFactory: (config: ConfigService) => [
        {
          ttl: config.get('THROTTLE_TTL'),
          limit: config.get('THROTTLE_LIMIT'),
        },
      ],
    }),
  ],
})
export class AppModule {}

You can also use the useClass syntax:

@Module({
  imports: [
    ThrottlerModule.forRootAsync({
      imports: [ConfigModule],
      useClass: ThrottlerConfigService,
    }),
  ],
})
export class AppModule {}

This is doable, as long as ThrottlerConfigService implements the interface ThrottlerOptionsFactory.

Storages

The built in storage is an in memory cache that keeps track of the requests made until they have passed the TTL set by the global options. You can drop in your own storage option to the storage option of the ThrottlerModule so long as the class implements the ThrottlerStorage interface.

Note: ThrottlerStorage can be imported from @nestjs/throttler.

Time Helpers

There are a couple of helper methods to make the timings more readable if you prefer to use them over the direct definition. @nestjs/throttler exports five different helpers, seconds, minutes, hours, days, and weeks. To use them, simply call seconds(5) or any of the other helpers, and the correct number of milliseconds will be returned.

Migrating to v5 from earlier versions

If you migrate to v5 from earlier versions, you need to wrap your options in an array.

If you are using a custom storage, you should wrap you ttl and limit in an array and assign it to the throttlers property of the options object.

Any @SkipThrottle() should now take in an object with string: boolean props. The strings are the names of the throttlers. If you do not have a name, pass the string 'default', as this is what will be used under the hood otherwise.

Migration examples for decorators:

// Before v5
@SkipThrottle()
@Throttle(10, 60)

// After v5 (with default throttler)
@SkipThrottle({ default: true })
@Throttle({ default: { limit: 10, ttl: 60000 } })

// After v5 (with named throttlers)
@SkipThrottle({ short: true, medium: true })
@Throttle({ short: { limit: 5, ttl: 1000 }, long: { limit: 100, ttl: 60000 } })

Any @Throttle() decorators should also now take in an object with string keys, relating to the names of the throttler contexts (again, 'default' if no name) and values of objects that have limit and ttl keys.

Important: The ttl is now in milliseconds. If you want to keep your ttl in seconds for readability, use the seconds helper from this package. It just multiplies the ttl by 1000 to make it in milliseconds.

Note: When using named throttlers, simply using @SkipThrottle() without parameters will not work as expected. See the Important note on using decorators with Named Throttlers section for details.

Community Storage Providers

• Redis (node-redis based)
• Redis (ioredis based)
• Mongo

Feel free to submit a PR with your custom storage provider being added to this list.

License

Nest is MIT licensed.

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