Add a code to customize the key.

README.md

@@ -49,6 +49,7 @@
   - [omitResponseHeaders](https://github.com/ozkanonur/nestjs-rate-limiter#-omitResponseHeaders)
   - [errorMessage](https://github.com/ozkanonur/nestjs-rate-limiter#-errorMessage)
   - [customResponseSchema](https://github.com/ozkanonur/nestjs-rate-limiter#-customResponseSchema)
+- [Override Functions](https://github.com/ozkanonur/nestjs-rate-limiter#override-functions)
 - [Benchmarks](https://github.com/ozkanonur/nestjs-rate-limiter#benchmarks)
 - [TODO List](https://github.com/ozkanonur/nestjs-rate-limiter#todo)
 
@@ -465,6 +466,22 @@ GraphQLModule.forRoot({
   <br>
 
   customResponseSchema option allows to provide customizable response schemas
+
+# Override Functions
+
+It's possible to override <code>getIpFromRequest</code> function by extending <code>RateLimiterGuard</code> class.
+
+```ts
+import { RateLimiterGuard } from 'nestjs-rate-limiter'
+import type { Request } from 'express'
+
+class ExampleRateLimiterGuard extends RateLimiterGuard {
+  protected getIpFromRequest(request: Request): string {
+    return request.get('x-forwarded-for');
+  }
+}
+```
+
 # Benchmarks
 
 1000 concurrent clients with maximum 2000 requests per sec during 30 seconds.

lib/default-options.ts

@@ -4,6 +4,7 @@ export const defaultRateLimiterOptions: RateLimiterOptions = {
 	for: 'Express',
 	type: 'Memory',
 	keyPrefix: 'global',
+	keyFactory: undefined,
 	points: 4,
 	pointsConsumed: 1,
 	inmemoryBlockOnConsumed: 0,

lib/rate-limiter.guard.ts

@@ -165,13 +165,24 @@ export class RateLimiterGuard implements CanActivate {
 		const request = this.httpHandler(context).req
 		const response = this.httpHandler(context).res
 
-		const rateLimiter: RateLimiterAbstract = await this.getRateLimiter(reflectedOptions)
-		const key = request.ip?.match(/\b\d{1,3}\.\d{1,3}\.\d{1,3}\.\d{1,3}\b/)?.[0]
+		if (reflectedOptions.keyFactory(request)) {
+			const rateLimiter: RateLimiterAbstract = await this.getRateLimiter(reflectedOptions)
+			const key = reflectedOptions.keyFactory(request)
 
-		await this.responseHandler(response, key, rateLimiter, points, pointsConsumed)
+			await this.responseHandler(response, key, rateLimiter, points, pointsConsumed)
+		} else {
+			const rateLimiter: RateLimiterAbstract = await this.getRateLimiter(reflectedOptions)
+			const key = this.getIpFromRequest(request)
+
+			await this.responseHandler(response, key, rateLimiter, points, pointsConsumed)
+		}
 		return true
 	}
 
+	protected getIpFromRequest(request: { ip: string }): string {
+		return request.ip?.match(/\b\d{1,3}\.\d{1,3}\.\d{1,3}\.\d{1,3}\b/)?.[0]
+	}
+
 	private httpHandler(context: ExecutionContext) {
 		if (this.options.for === 'ExpressGraphql') {
 			return {

lib/rate-limiter.interface.ts

@@ -6,6 +6,7 @@ export interface RateLimiterOptions {
 	for?: 'Express' | 'Fastify' | 'Microservice' | 'ExpressGraphql' | 'FastifyGraphql'
 	type?: 'Memory' | 'Redis' | 'Memcache' | 'Postgres' | 'MySQL' | 'Mongo'
 	keyPrefix?: string
+	keyFactory?: (request: Request) => {}
 	points?: number
 	pointsConsumed?: number
 	inmemoryBlockDuration?: number