NgHttpCaching

Cache for HTTP requests in Angular application.

Description

Sometime there is a need to cache the HTTP requests so that browser doesn’t have to hit server to fetch same data when same service is invoked serially or in parallel. NgHttpCaching intercept all request are made, try to retrieve a cached instance of the response and then return the cached response or send the request to the backend. Once the operation has completed cache the response.

See the stackblitz demo.

Features

✅ HTTP caching
✅ Handles simultaneous/parallel requests
✅ Automatic garbage collector of cache
✅ More than 90% unit tested
✅ LocalStorage, SessionStorage, MemoryStorage and custom cache storage
✅ Check response headers cache-control and expires
✅ Automatic cache invalidation on mutations (POST, PUT, DELETE, PATCH)
✅ Server side rendering (SSR) safe

Get Started

Step 1: install ng-http-caching

npm i ng-http-caching

Step 2: Provide NgHttpCaching into your bootstrapApplication, eg.:

import { bootstrapApplication } from '@angular/platform-browser';
import { provideHttpClient, withInterceptorsFromDi } from '@angular/common/http';
import { AppComponent } from './app.component';
import { provideNgHttpCaching } from 'ng-http-caching';

bootstrapApplication(AppComponent, {
  providers: [
    provideNgHttpCaching(),
    provideHttpClient(withInterceptorsFromDi())
  ]
});

if you want configure ng-http-caching, you can pass a configuration, eg.:

import { bootstrapApplication } from '@angular/platform-browser';
import { provideHttpClient, withInterceptorsFromDi } from '@angular/common/http';
import { AppComponent } from './app.component';
import { provideNgHttpCaching, NgHttpCachingConfig } from 'ng-http-caching';

// your config...
const ngHttpCachingConfig: NgHttpCachingConfig = {
  lifetime: 1000 * 10 // cache expire after 10 seconds
};

bootstrapApplication(AppComponent, {
  providers: [
    provideNgHttpCaching(ngHttpCachingConfig),
    provideHttpClient(withInterceptorsFromDi())
  ]
});

Config

This is all the configuration interface, see below for the detail of each config.

// all configuration are optionally
export interface NgHttpCachingConfig {
  version?: string;
  lifetime?: number;
  maxSize?: number;
  allowedMethod?: string[];
  cacheStrategy?: NgHttpCachingStrategy;
  checkResponseHeaders?: boolean;
  store?:
    | NgHttpCachingStorageInterface
    | NgHttpCachingNgSimpleStateSentinel
    | (() => NgHttpCachingStorageInterface);
  isExpired?: (entry: NgHttpCachingEntry) => boolean | undefined | void;
  isValid?: (entry: NgHttpCachingEntry) => boolean | undefined | void;
  isCacheable?: (req: HttpRequest<any>) => boolean | undefined | void;
  getKey?: (req: HttpRequest<any>) => string | undefined | void;
  clearCacheOnMutation?: NgHttpCachingMutationStrategy | boolean | ((req: HttpRequest<any>) => boolean | undefined | void);
}

version (string - default: VERSION.major)

Cache version. When you have a breaking change, change the version, and it'll delete the current cache automatically. The default value is Angular major version (eg. 13), in this way, the cache is invalidated on every Angular upgrade.

lifetime (number - default: 3.600.000)

Number of millisecond that a response is stored in the cache. You can set specific "lifetime" for each request by add the header X-NG-HTTP-CACHING-LIFETIME (see example below).

maxSize (number - default: 0)

Maximum number of entries kept into the cache store. When the limit is exceeded, the least recently used entries are evicted. 0 (the default) means no limit.

const ngHttpCachingConfig: NgHttpCachingConfig = {
  maxSize: 100, // keep at most 100 responses
};

The access time is tracked in memory by the service. For a persistent store (localStorage, sessionStorage) the entries restored by a previous page load have no known access time, so they are evicted by the time they were added until they are read again.

checkResponseHeaders (boolean - default false);

If true response headers cache-control and expires are respected. Cache-Control: no-store/no-cache, and an Expires already in the past, keep the response out of the cache; max-age drives the entry lifetime. The Age header is subtracted from max-age, so a response a CDN or proxy has already been holding isn't kept for the full max-age again — when Age is greater than or equal to max-age the response is already stale and isn't cached at all.

allowedMethod (string[] - default: ['GET', 'HEAD'])

Array of allowed HTTP methods to cache. You can allow multiple methods, eg.: ['GET', 'POST', 'PUT', 'DELETE', 'HEAD'] or allow all methods by: ['ALL']. If allowedMethod is an empty array ([]), no response are cached. Warning! NgHttpCaching use the full url (url with query parameters) as unique key for the cached response, this is correct for the GET request but is potentially wrong for other type of request (eg. POST, PUT). You can set a different "key" by customizing the getKey config method (see getKey section).

cacheStrategy (enum NgHttpCachingStrategy - default: NgHttpCachingStrategy.ALLOW_ALL)

Set the cache strategy, possible strategies are:

NgHttpCachingStrategy.ALLOW_ALL: All request are cacheable if HTTP method is into allowedMethod;
NgHttpCachingStrategy.DISALLOW_ALL: Only the request with X-NG-HTTP-CACHING-ALLOW-CACHE header are cacheable if HTTP method is into allowedMethod;

store (class of NgHttpCachingStorageInterface - default: NgHttpCachingMemoryStorage)

Set the cache store. You can implement your custom store by implement the NgHttpCachingStorageInterface interface, eg.:

import { NgHttpCachingConfig, NgHttpCachingStorageInterface } from 'ng-http-caching';

class MyCustomStore implements NgHttpCachingStorageInterface {
  // ... your logic
}

const ngHttpCachingConfig: NgHttpCachingConfig = {
  store: new MyCustomStore(),
};

the default store is withNgHttpCachingMemoryStorage, an in-memory cache store:

import { NgHttpCachingConfig, withNgHttpCachingMemoryStorage } from 'ng-http-caching';

const ngHttpCachingConfig: NgHttpCachingConfig = {
  store: withNgHttpCachingMemoryStorage(),
};

there is also a withNgHttpCachingLocalStorage a cache store with persistence into localStorage:

import { NgHttpCachingConfig, withNgHttpCachingLocalStorage } from 'ng-http-caching';

const ngHttpCachingConfig: NgHttpCachingConfig = {
  store: withNgHttpCachingLocalStorage(),
};

and a withNgHttpCachingSessionStorage a cache store with persistence into sessionStorage:

import { NgHttpCachingConfig, withNgHttpCachingSessionStorage } from 'ng-http-caching';

const ngHttpCachingConfig: NgHttpCachingConfig = {
  store: withNgHttpCachingSessionStorage(),
};

Both are safe to use with server side rendering: when localStorage/sessionStorage isn't reachable (SSR, prerendering, sandboxed iframe, storage disabled by the user) they transparently fall back to an in-memory storage, so nothing is persisted and nothing throws.

Server side rendering: pass a factory, not an instance

store also accepts a factory. This matters with server side rendering: the config object is created once, when its module is loaded, so a store instance put in there is shared by every request the server renders — and with it the cached responses of every user. A factory is invoked once per NgHttpCachingService, so each rendered request gets its own:

import { NgHttpCachingConfig, withNgHttpCachingMemoryStorage } from 'ng-http-caching';

const ngHttpCachingConfig: NgHttpCachingConfig = {
  // ✅ one store per request
  store: () => withNgHttpCachingMemoryStorage(),
  // ❌ one store shared by all the server side rendered requests
  // store: withNgHttpCachingMemoryStorage(),
};

In the browser there is a single user per process, so both forms behave the same.

and a withNgHttpCachingNgSimpleState adapter for use ng-simple-state as the cache storage.

To use this adapter, you must install ng-simple-state in your project:

npm i ng-simple-state

Then you can use it like this:

import { bootstrapApplication } from '@angular/platform-browser';
import { provideHttpClient, withInterceptorsFromDi } from '@angular/common/http';
import { provideNgHttpCaching } from 'ng-http-caching';
import { withNgHttpCachingNgSimpleState } from 'ng-http-caching/ng-simple-state';
import { AppComponent } from './app.component';

bootstrapApplication(AppComponent, {
  providers: [
    provideNgHttpCaching({
      store: withNgHttpCachingNgSimpleState(),
    }),
    provideHttpClient(withInterceptorsFromDi())
  ]
});

isExpired (function - default see NgHttpCachingService.isExpired());

If this function return true the request is expired and a new request is send to backend, if return false isn't expired. If the result is undefined, the normal behaviour is provided. Example of customization:

import { NgHttpCachingConfig, NgHttpCachingEntry } from 'ng-http-caching';

const ngHttpCachingConfig: NgHttpCachingConfig = {
  isExpired: (entry: NgHttpCachingEntry): boolean | undefined => {
      // In this example a special API endpoint (/my-endpoint) send into the body response
      // an expireAt property (an ISO date string). Only for this endpoint the expiration
      // is provided by expireAt value.
      // For all the other endpoint normal behaviour is provided.
      if( entry.request.urlWithParams.indexOf('/my-endpoint') !== -1 ){
        // return true when the entry is expired, so a new request is sent to the backend
        return Date.parse(entry.response.body.expireAt) <= Date.now();
      }
      // by returning "undefined" normal "ng-http-caching" workflow is applied
      return undefined;
    },
};

isValid (function - default see NgHttpCachingService.isValid());

If this function return true the cache entry is valid and can be stored, if return false isn't valid. If the result is undefined, the normal behaviour is provided. Default behaviour is whether the status code falls in the 2xx range and response headers cache-control and expires allow cache. Example of customization:

import { NgHttpCachingConfig, NgHttpCachingEntry } from 'ng-http-caching';

const ngHttpCachingConfig: NgHttpCachingConfig = {
  isValid: (entry: NgHttpCachingEntry): boolean | undefined => {
      // In this example only response with status code 200 can be stored into the cache
      return entry.response.status === 200;
    },
};

isCacheable (function - default see NgHttpCachingService.isCacheable());

If this function return true the request is cacheable, if return false isn't cacheable. If the result is undefined, the normal behaviour is provided. Example of customization:

import { NgHttpCachingConfig } from 'ng-http-caching';

const ngHttpCachingConfig: NgHttpCachingConfig = {
  isCacheable: (req: HttpRequest<any>): boolean | undefined => {
      // In this example the /my-endpoint isn't cacheable.
      // For all the other endpoint normal behaviour is provided.
      if( req.urlWithParams.indexOf('/my-endpoint') !== -1 ){
        return false;
      }
      // by returning "undefined" normal "ng-http-caching" workflow is applied
      return undefined;
    },
};

getKey (function - default see NgHttpCachingService.getKey());

This function return the unique key (string) for store the response into the cache. If the result is undefined, the normal behaviour is provided. Example of customization:

import { NgHttpCachingConfig } from 'ng-http-caching';
import * as hash from 'object-hash';  // install object-hash with: npm i object-hash

const hashOptions = {
  algorithm: 'md5',
  encoding: 'hex'
};

const ngHttpCachingConfig: NgHttpCachingConfig = {
  allowedMethod: ['GET', 'POST', 'PUT', 'DELETE', 'HEAD'],
  getKey: (req: HttpRequest<any>): string | undefined => {
    // In this example the full request is hashed for provide an unique key for the cache.
    // This is important if you want support method like POST or PUT.
    return req.method + '@' + req.urlWithParams + '@' + hash(req.params, hashOptions) + '@' + hash(req.body, hashOptions);
  },
};

clearCacheOnMutation (enum NgHttpCachingMutationStrategy | boolean | Function - default: NgHttpCachingMutationStrategy.NONE)

Set the mutation strategy for automatically clear the cache when a mutation request (POST, PUT, DELETE, PATCH) is successful. Possible strategies are:

NgHttpCachingMutationStrategy.NONE (or false): No automatic invalidation.
NgHttpCachingMutationStrategy.ALL (or true): Clears the entire cache store on any successful mutation.
NgHttpCachingMutationStrategy.IDENTICAL: Clears entries with the same URL (ignoring method and query params).
NgHttpCachingMutationStrategy.COLLECTION: Clears entries with the same URL AND its parent collection URL (eg. DELETE /api/users/24 invalidate also GET /api/users).

IDENTICAL and COLLECTION match the URL of the cached request, not the cache key, so they keep working with a custom getKey (see the getKey section).
Function: Custom logic: (req: HttpRequest<any>) => boolean. It is called only for mutation requests; returning true clears the entire cache store, returning false (or undefined) skips the invalidation for that request.

Example of customization:

import { NgHttpCachingConfig, NgHttpCachingMutationStrategy } from 'ng-http-caching';

const ngHttpCachingConfig: NgHttpCachingConfig = {
  // clear the entire cache only if the mutation (POST, PUT, DELETE, PATCH)
  // is on a specific endpoint
  clearCacheOnMutation: (req) => req.url.includes('/api/critical-data')
};

Headers

NgHttpCaching use some custom headers for customize the caching behaviour. The supported headers are exported from NgHttpCachingHeaders:

export const NgHttpCachingHeaders = {
  ALLOW_CACHE: 'X-NG-HTTP-CACHING-ALLOW-CACHE',
  DISALLOW_CACHE: 'X-NG-HTTP-CACHING-DISALLOW-CACHE',
  LIFETIME: 'X-NG-HTTP-CACHING-LIFETIME',
  TAG: 'X-NG-HTTP-CACHING-TAG',
};

All those headers are removed before send the request to the backend.

X-NG-HTTP-CACHING-ALLOW-CACHE (string: any value);

If you have choose the DISALLOW_ALL cache strategy, you can mark specific request as cacheable by adding the header X-NG-HTTP-CACHING-ALLOW-CACHE, eg.:

this.http.get('https://my-json-server.typicode.com/typicode/demo/db', {
  headers: {
    [NgHttpCachingHeaders.ALLOW_CACHE]: '1',
  }
}).subscribe(e => console.log(e));

X-NG-HTTP-CACHING-DISALLOW-CACHE (string: any value);

You can disallow specific request by add the header X-NG-HTTP-CACHING-DISALLOW-CACHE, eg.:

this.http.get('https://my-json-server.typicode.com/typicode/demo/db', {
  headers: { 
    [NgHttpCachingHeaders.DISALLOW_CACHE]: '1',
  }
}).subscribe(e => console.log(e));

X-NG-HTTP-CACHING-LIFETIME (string: number of millisecond);

You can set specific lifetime for request by add the header X-NG-HTTP-CACHING-LIFETIME with a string value as the number of millisecond, eg.:

this.http.get('https://my-json-server.typicode.com/typicode/demo/db', {
  headers: {
    [NgHttpCachingHeaders.LIFETIME]: (1000 * 60 * 60 * 24 * 365).toString(), // one year
  }
}).subscribe(e => console.log(e));

X-NG-HTTP-CACHING-TAG (string: tag name);

You can tag multiple request by adding special header X-NG-HTTP-CACHING-TAG with the same tag and using NgHttpCachingService.clearCacheByTag(tag: string) for delete all the tagged request. Eg.:

this.http.get('https://my-json-server.typicode.com/typicode/demo/db?id=1', {
  headers: {
    [NgHttpCachingHeaders.TAG]: 'foo',
  }
}).subscribe(e => console.log(e));

HttpContext

You can override NgHttpCachingConfig methods:

{
  isExpired?: (entry: NgHttpCachingEntry) => boolean | undefined | void;
  isValid?: (entry: NgHttpCachingEntry) => boolean | undefined | void;
  isCacheable?: (req: HttpRequest<any>) => boolean | undefined | void;
  getKey?: (req: HttpRequest<any>) => string | undefined | void;
  clearCacheOnMutation?: NgHttpCachingMutationStrategy | boolean | ((req: HttpRequest<any>) => boolean | undefined | void);
}

with HttpContextToken, eg.:

import { withNgHttpCachingContext } from 'ng-http-caching';

const context = withNgHttpCachingContext({
  isExpired: (entry: NgHttpCachingEntry) => {
    console.log('context:isExpired', entry);
  },
  isCacheable: (req: HttpRequest<any>) => {
    console.log('context:isCacheable', req);
  },
  getKey: (req: HttpRequest<any>) => {
    console.log('context:getKey', req);
  },
  isValid: (entry: NgHttpCachingEntry) => {
    console.log('context:isValid', entry);
  }
});
this.http.get('https://my-json-server.typicode.com/typicode/demo/db?id=1', { context }).subscribe(e => console.log(e));

Cache service

You can inject into your component the NgHttpCachingService that expose some utils methods:

export class NgHttpCachingService {

  /**
   * Return the config
   */
  getConfig(): Readonly<NgHttpCachingConfig>;

  /**
   * Return the queue map
   */
  getQueue(): Readonly<Map<string, Observable<HttpEvent<any>>>>;

  /**
   * Return the cache store
   */
  getStore(): Readonly<NgHttpCachingStorageInterface>;

  /**
   * Return response from cache
   */
  getFromCache<K, T>(req: HttpRequest<K>): Readonly<HttpResponse<T>> | undefined;

  /**
   * Add response to cache
   */
  addToCache<K, T>(req: HttpRequest<K>, res: HttpResponse<T>): boolean;

  /**
   * Delete response from cache
   */
  deleteFromCache<K>(req: HttpRequest<K>): boolean;

  /**
   * Clear the cache
   */
  clearCache(): void;

  /**
   * Clear the cache by key
   */
  clearCacheByKey(key: string): boolean;

  /**
   * Clear the cache by keys
   */
  clearCacheByKeys(keys: Array<string>): number;

  /**
   * Clear the cache by regex
   */
  clearCacheByRegex<K, T>(regex: RegExp): number;

  /**
   * Clear the cache by TAG
   */
  clearCacheByTag<K, T>(tag: string): number;

  /**
   * Clear the cache according to the `clearCacheOnMutation` strategy.
   * Called automatically by the interceptor on every successful mutation.
   */
  clearCacheByMutation<K>(req: HttpRequest<K>): boolean;

  /**
   * Run garbage collector (delete expired cache entry)
   */
  runGc<K, T>(): boolean;

  /**
   * Return true if cache entry is expired
   */
  isExpired<K, T>(entry: NgHttpCachingEntry<K, T>): boolean;

  /**
   * Return true if cache entry is valid for store in the cache
   * Default behaviour is whether the status code falls in the 2xx range and response headers cache-control and expires allow cache.
   */
  isValid<K, T>(entry: NgHttpCachingEntry<K, T>): boolean;

  /**
   * Return true if the request is cacheable
   */
  isCacheable<K>(req: HttpRequest<K>): boolean;

  /**
   * Return the cache key.
   * Default key is http method plus url with query parameters, eg.:
   * `GET@https://github.com/nigrosimone/ng-http-caching`
   */
  getKey<K>(req: HttpRequest<K>): string;

  /**
   * Return observable from cache
   */
  getFromQueue<K, T>(req: HttpRequest<K>): Observable<HttpEvent<T>> | undefined;

  /**
   * Add observable to cache
   */
  addToQueue<K, T>(req: HttpRequest<K>, obs: Observable<HttpEvent<T>>): void;

  /**
   * Delete observable from cache
   */
  deleteFromQueue<K>(req: HttpRequest<K>): boolean;
}

Examples

Below there are some examples of use case.

Example: exclude specific request from cache

You can disallow specific request by add the header X-NG-HTTP-CACHING-DISALLOW-CACHE, eg.:

import { Component, inject } from '@angular/core';
import { HttpClient } from '@angular/common/http';
import { NgHttpCachingHeaders } from 'ng-http-caching';

@Component({
  selector: 'app-root',
  templateUrl: './app.component.html',
  styleUrls: ['./app.component.scss']
})
export class AppComponent {
  private readonly http = inject(HttpClient);

  constructor() {
    // This request will never cache.
    // Note: all the "special" headers in NgHttpCachingHeaders are removed before send the request to the backend.
    this.http.get('https://my-json-server.typicode.com/typicode/demo/db', {
      headers: {
        [NgHttpCachingHeaders.DISALLOW_CACHE]: '1',
      }
    }).subscribe(e => console.log(e));
  }
}

Example: set specific lifetime for request

You can set specific lifetime for request by add the header X-NG-HTTP-CACHING-LIFETIME with a string value as the number of millisecond, eg.:

import { Component, inject } from '@angular/core';
import { HttpClient } from '@angular/common/http';
import { NgHttpCachingHeaders } from 'ng-http-caching';

@Component({
  selector: 'app-root',
  templateUrl: './app.component.html',
  styleUrls: ['./app.component.scss']
})
export class AppComponent {
  private readonly http = inject(HttpClient);

  constructor() {
    // This request will expire from 365 days.
    // Note: all the "special" headers in NgHttpCachingHeaders are removed before send the request to the backend.
    this.http.get('https://my-json-server.typicode.com/typicode/demo/db', {
      headers: {
        [NgHttpCachingHeaders.LIFETIME]: (1000 * 60 * 60 * 24 * 365).toString(),
      }
    }).subscribe(e => console.log(e));
  }
}

Example: mark specific request as cacheable (if cache strategy is DISALLOW_ALL)

If you have choose the DISALLOW_ALL cache strategy, you can mark specific request as cacheable by adding the header X-NG-HTTP-CACHING-ALLOW-CACHE, eg.:

import { Component, inject } from '@angular/core';
import { HttpClient } from '@angular/common/http';
import { NgHttpCachingHeaders } from 'ng-http-caching';

@Component({
  selector: 'app-root',
  templateUrl: './app.component.html',
  styleUrls: ['./app.component.scss']
})
export class AppComponent {
  private readonly http = inject(HttpClient);

  constructor() {
    // This request is marked as cacheable (this is necessary only if cache strategy is DISALLOW_ALL)
    // Note: all the "special" headers in NgHttpCachingHeaders are removed before send the request to the backend.
    this.http.get('https://my-json-server.typicode.com/typicode/demo/db', {
      headers: {
        [NgHttpCachingHeaders.ALLOW_CACHE]: '1',
      }
    }).subscribe(e => console.log(e));
  }
}

Example: clear/flush all the cache

If user switch the account (logout/login) or the application language, maybe ca be necessary clear all the cache, eg.:

import { Component, inject } from '@angular/core';
import { NgHttpCachingService } from 'ng-http-caching';

@Component({
  selector: 'app-root',
  templateUrl: './app.component.html',
  styleUrls: ['./app.component.scss']
})
export class AppComponent {
  private readonly ngHttpCachingService = inject(NgHttpCachingService);

  clearCache(): void {
    // Clear all the cache
    this.ngHttpCachingService.clearCache();
  }
}

Example: clear/flush specific cache entry

If you want delete some cache entry, eg.:

import { Component, inject } from '@angular/core';
import { NgHttpCachingService } from 'ng-http-caching';

@Component({
  selector: 'app-root',
  templateUrl: './app.component.html',
  styleUrls: ['./app.component.scss']
})
export class AppComponent {
  private readonly ngHttpCachingService = inject(NgHttpCachingService);

  clearCache(key: string): boolean {
    // Clear the cache for the provided key
    return this.ngHttpCachingService.clearCacheByKey(key);
  }
}

Example: clear/flush specific cache entry by RegEx

If you want delete some cache entry by RegEx, eg.:

import { Component, inject } from '@angular/core';
import { NgHttpCachingService } from 'ng-http-caching';

@Component({
  selector: 'app-root',
  templateUrl: './app.component.html',
  styleUrls: ['./app.component.scss']
})
export class AppComponent {
  private readonly ngHttpCachingService = inject(NgHttpCachingService);

  clearCacheByRegex(regEx: RegExp): void {
    // Clear the cache for the key that match regex
    this.ngHttpCachingService.clearCacheByRegex(regEx);
  }
}

Example: TAG request and clear/flush specific cache entry by TAG

You can tag multiple request by adding special header X-NG-HTTP-CACHING-TAG with the same tag and using NgHttpCachingService.clearCacheByTag(tag: string) for delete all the tagged request. Eg.:

import { Component, inject } from '@angular/core';
import { HttpClient } from '@angular/common/http';
import { NgHttpCachingService, NgHttpCachingHeaders } from 'ng-http-caching';

@Component({
  selector: 'app-root',
  templateUrl: './app.component.html',
  styleUrls: ['./app.component.scss']
})
export class AppComponent {
  private readonly ngHttpCachingService = inject(NgHttpCachingService);
  private readonly http = inject(HttpClient);

  constructor() {
    // This request is tagged with "foo" keyword. You can tag multiple requests with the same tag and 
    // using NgHttpCachingService.clearCacheByTag("foo") for delete all the tagged request.
    this.http.get('https://my-json-server.typicode.com/typicode/demo/db?id=1', {
      headers: {
        [NgHttpCachingHeaders.TAG]: 'foo',
      }
    }).subscribe(e => console.log(e));

    // This request is also tagged with "foo" keyword, and has another tag "baz".
    // You can add multiple tags comma separated.
    this.http.get('https://my-json-server.typicode.com/typicode/demo/db?id=2', {
      headers: {
        [NgHttpCachingHeaders.TAG]: 'foo,baz',
      }
    }).subscribe(e => console.log(e));
  }

  clearCacheForFoo(): void {
    // Clear the cache for all the entry have the tag 'foo'
    this.ngHttpCachingService.clearCacheByTag('foo');
  }
}

Limitations

NgHttpCaching is a TTL cache with request deduplication, not a full implementation of the HTTP caching semantics. Know what it doesn't do before you rely on it.

⚠️ The cache key ignores the request headers

The default key is method@url (see the getKey section): two requests to the same URL share the same cache entry even if they carry different headers. For an Authorization header this means that, after a user switch, the previous user's response can still be served from the cache.

If you cache anything user specific, do one of the following:

clear the cache when the identity changes — the simplest and safest option:

// on login, logout, tenant or language switch
this.ngHttpCachingService.clearCache();

or make the identity part of the key:

const ngHttpCachingConfig: NgHttpCachingConfig = {
  getKey: (req) => req.method + '@' + req.urlWithParams + '@' + (req.headers.get('Authorization') ?? ''),
};

or keep user specific requests out of the cache entirely, with the X-NG-HTTP-CACHING-DISALLOW-CACHE header or a custom isCacheable.

`Vary` is not supported

The Vary response header is ignored. A response negotiated on Accept-Language, Accept-Encoding or any other header is served to every request matching the cache key, whatever the negotiation was. Use getKey to include the relevant headers yourself.

No conditional revalidation

There is no ETag/Last-Modified handling and no conditional request (If-None-Match, If-Modified-Since, 304 Not Modified). An entry is either fresh, and used as is, or expired, and refetched in full. Likewise no-cache is treated as "don't store" rather than "store, but revalidate before use".

Alternatives

Aren't you satisfied? there are some valid alternatives:

Support

This is an open-source project. Star this repository, if you like it, or even donate. Thank you so much!

My other libraries

I have published some other Angular libraries, take a look:

Name		Name	Last commit message	Last commit date
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.claude		.claude
.github		.github
examples/stackblitz		examples/stackblitz
projects		projects
.editorconfig		.editorconfig
.git-blame-ignore-revs		.git-blame-ignore-revs
.gitattributes		.gitattributes
.gitignore		.gitignore
.prettierignore		.prettierignore
.prettierrc.json		.prettierrc.json
CHANGELOG.md		CHANGELOG.md
CODE_OF_CONDUCT.md		CODE_OF_CONDUCT.md
LICENSE		LICENSE
README.md		README.md
README_Angular.md		README_Angular.md
angular.json		angular.json
eslint.config.mjs		eslint.config.mjs
package-lock.json		package-lock.json
package.json		package.json
prj.code-workspace		prj.code-workspace
publish.bat		publish.bat
tsconfig.json		tsconfig.json

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