Avoiding caching of GET requests in Angular 2 for Internet Explorer 11

Question

Avoiding caching of GET requests in Angular 2 for Internet Explorer 11

My rest endpoint successfully returns a list when calling GET, and I can also use POST to add new items or DELETE to remove them. This functionality is working perfectly in Firefox and Chrome, with the additional note that POST and DELETE also work in IE11. However, there seems to be an issue with the GET method in IE11 - it only works upon the initial page load. When refreshing the page, cached data is returned instead of the updated list. I have come across posts discussing this problem in Angular 1, but I haven't found any solutions specific to Angular 2 (release candidate 1).

javascript angular typescript internet-explorer-11 http-caching

Answer 1

Answer №1

To easily add no-cache headers in Angular 2 and beyond, you can override the RequestOptions like so:

import { Injectable } from '@angular/core';
import { BaseRequestOptions, Headers } from '@angular/http';

@Injectable()
export class CustomRequestOptions extends BaseRequestOptions {
    headers = new Headers({
        'Cache-Control': 'no-cache',
        'Pragma': 'no-cache',
        'Expires': 'Sat, 01 Jan 2000 00:00:00 GMT'
    });
}

Module:

@NgModule({
    ...
    providers: [
        ...
        { provide: RequestOptions, useClass: CustomRequestOptions }
    ]
})

Answer 2

To easily add no-cache headers in Angular 2 and beyond, you can override the RequestOptions like so:

import { Injectable } from '@angular/core';
import { BaseRequestOptions, Headers } from '@angular/http';

@Injectable()
export class CustomRequestOptions extends BaseRequestOptions {
    headers = new Headers({
        'Cache-Control': 'no-cache',
        'Pragma': 'no-cache',
        'Expires': 'Sat, 01 Jan 2000 00:00:00 GMT'
    });
}

Module:

@NgModule({
    ...
    providers: [
        ...
        { provide: RequestOptions, useClass: CustomRequestOptions }
    ]
})

Answer 3

Answer №2

Encountered a similar issue today, specifically with Internet Explorer. Within my project, I am utilizing httpclient, which lacks the presence of BaseRequestOptions. The solution lies in implementing Http_Interceptor!

import { HttpHandler,
    HttpProgressEvent,
    HttpInterceptor,
    HttpSentEvent,
    HttpHeaderResponse,
    HttpUserEvent,
    HttpRequest,
    HttpResponse } from '@angular/common/http';
import { Observable } from 'rxjs/Observable';

export class CustomHttpInterceptorService implements HttpInterceptor {
    intercept(req: HttpRequest<any>, next: HttpHandler):
      Observable<HttpSentEvent | HttpHeaderResponse | HttpProgressEvent | HttpResponse<any> | HttpUserEvent<any>> {
      const nextReq = req.clone({
        headers: req.headers.set('Cache-Control', 'no-cache')
          .set('Pragma', 'no-cache')
          .set('Expires', 'Sat, 01 Jan 2000 00:00:00 GMT')
          .set('If-Modified-Since', '0')
      });

      return next.handle(nextReq);
  }
}

Don't forget to include the following in your module:

@NgModule({
    ...
    providers: [
        ...
        { provide: HTTP_INTERCEPTORS, useClass: CustomHttpInterceptorService, multi: true }
    ]
})

Answer 4

Encountered a similar issue today, specifically with Internet Explorer. Within my project, I am utilizing httpclient, which lacks the presence of BaseRequestOptions. The solution lies in implementing Http_Interceptor!

import { HttpHandler,
    HttpProgressEvent,
    HttpInterceptor,
    HttpSentEvent,
    HttpHeaderResponse,
    HttpUserEvent,
    HttpRequest,
    HttpResponse } from '@angular/common/http';
import { Observable } from 'rxjs/Observable';

export class CustomHttpInterceptorService implements HttpInterceptor {
    intercept(req: HttpRequest<any>, next: HttpHandler):
      Observable<HttpSentEvent | HttpHeaderResponse | HttpProgressEvent | HttpResponse<any> | HttpUserEvent<any>> {
      const nextReq = req.clone({
        headers: req.headers.set('Cache-Control', 'no-cache')
          .set('Pragma', 'no-cache')
          .set('Expires', 'Sat, 01 Jan 2000 00:00:00 GMT')
          .set('If-Modified-Since', '0')
      });

      return next.handle(nextReq);
  }
}

Don't forget to include the following in your module:

@NgModule({
    ...
    providers: [
        ...
        { provide: HTTP_INTERCEPTORS, useClass: CustomHttpInterceptorService, multi: true }
    ]
})

Answer 5

Answer №3

To resolve the caching issue in Angular with Internet Explorer, make sure to include the headers 'Pragma', 'no-cache', and 'If-Modified-Since' in each 'GET' request. For more information on this topic, refer to a previous stackoverflow response about Angular IE Caching issue for $http.

In Angular 2, the interceptor's functionality is no longer supported. Instead, you should extend the http as described in this thread: What is httpinterceptor equivalent in angular2?

For Angular 4.3 and above, the new HttpClient service includes support for interceptors.

Answer 6

To resolve the caching issue in Angular with Internet Explorer, make sure to include the headers 'Pragma', 'no-cache', and 'If-Modified-Since' in each 'GET' request. For more information on this topic, refer to a previous stackoverflow response about Angular IE Caching issue for $http.

In Angular 2, the interceptor's functionality is no longer supported. Instead, you should extend the http as described in this thread: What is httpinterceptor equivalent in angular2?

For Angular 4.3 and above, the new HttpClient service includes support for interceptors.

Answer 7

Answer №4

Note: Please refer to the comment below as this solution may not be required in most cases.

Building on Jimmy Ho's response, my goal is to specifically prevent caching of API calls without affecting other static content that can benefit from caching. Since all my API calls have URLs containing "/api/", I modified Jimmy Ho's code to include a check that adds cache headers only for requests with "/api/" in the URL:

import { HttpHandler,
    HttpProgressEvent,
    HttpInterceptor,
    HttpSentEvent,
    HttpHeaderResponse,
    HttpUserEvent,
    HttpRequest,
    HttpResponse } from '@angular/common/http';
import { Observable } from 'rxjs/Observable';

export class CustomHttpInterceptorService implements HttpInterceptor {
    intercept(req: HttpRequest<any>, next: HttpHandler):
    Observable<HttpSentEvent | HttpHeaderResponse | HttpProgressEvent | HttpResponse<any> | HttpUserEvent<any>> {
    // Disable caching for API calls.
    if (req.url.indexOf('/api/') >= 0) {
        const nextReq = req.clone({
            headers: req.headers.set('Cache-Control', 'no-cache')
                .set('Pragma', 'no-cache')
                .set('Expires', 'Sat, 01 Jan 2000 00:00:00 GMT')
                .set('If-Modified-Since', '0')
        });

        return next.handle(nextReq);
    } else {
        // Leave the request unchanged.
        return next.handle(req);
    }
}

}

Answer 8

Note: Please refer to the comment below as this solution may not be required in most cases.

Building on Jimmy Ho's response, my goal is to specifically prevent caching of API calls without affecting other static content that can benefit from caching. Since all my API calls have URLs containing "/api/", I modified Jimmy Ho's code to include a check that adds cache headers only for requests with "/api/" in the URL:

import { HttpHandler,
    HttpProgressEvent,
    HttpInterceptor,
    HttpSentEvent,
    HttpHeaderResponse,
    HttpUserEvent,
    HttpRequest,
    HttpResponse } from '@angular/common/http';
import { Observable } from 'rxjs/Observable';

export class CustomHttpInterceptorService implements HttpInterceptor {
    intercept(req: HttpRequest<any>, next: HttpHandler):
    Observable<HttpSentEvent | HttpHeaderResponse | HttpProgressEvent | HttpResponse<any> | HttpUserEvent<any>> {
    // Disable caching for API calls.
    if (req.url.indexOf('/api/') >= 0) {
        const nextReq = req.clone({
            headers: req.headers.set('Cache-Control', 'no-cache')
                .set('Pragma', 'no-cache')
                .set('Expires', 'Sat, 01 Jan 2000 00:00:00 GMT')
                .set('If-Modified-Since', '0')
        });

        return next.handle(nextReq);
    } else {
        // Leave the request unchanged.
        return next.handle(req);
    }
}

}

Answer 9

Answer №5

One way to customize HTTP requests is by using a http request interceptor to add or modify headers. Below is an alternative method for setting headers on HTTP request interceptors in newer versions of Angular (Angular 4 and above). This approach focuses on updating specific headers without affecting important ones like the authorization header.

// custom-interceptor.service.ts
import { Injectable } from '@angular/core';
import {
  HttpInterceptor,
  HttpRequest,
  HttpHandler,
} from '@angular/common/http';

@Injectable()
export class CustomInterceptor implements HttpInterceptor {

  intercept(req: HttpRequest<any>, next: HttpHandler) {
    const httpRequest = req.clone({
      headers: req.headers
        .set('Custom-Header', 'value')
        .set('Another-Header', 'another value')
        .set('Expires', 'Sat, 01 Jan 2000 00:00:00 GMT')
    })

    return next.handle(httpRequest)
  }
}

// app.module.ts

import { HTTP_INTERCEPTORS } from '@angular/common/http'
import { CustomInterceptor } from './custom-interceptor.service';

// within providers array
providers: [{ provide: HTTP_INTERCEPTORS, useClass: CustomInterceptor, multi: true }]

Answer 10

One way to customize HTTP requests is by using a http request interceptor to add or modify headers. Below is an alternative method for setting headers on HTTP request interceptors in newer versions of Angular (Angular 4 and above). This approach focuses on updating specific headers without affecting important ones like the authorization header.

// custom-interceptor.service.ts
import { Injectable } from '@angular/core';
import {
  HttpInterceptor,
  HttpRequest,
  HttpHandler,
} from '@angular/common/http';

@Injectable()
export class CustomInterceptor implements HttpInterceptor {

  intercept(req: HttpRequest<any>, next: HttpHandler) {
    const httpRequest = req.clone({
      headers: req.headers
        .set('Custom-Header', 'value')
        .set('Another-Header', 'another value')
        .set('Expires', 'Sat, 01 Jan 2000 00:00:00 GMT')
    })

    return next.handle(httpRequest)
  }
}

// app.module.ts

import { HTTP_INTERCEPTORS } from '@angular/common/http'
import { CustomInterceptor } from './custom-interceptor.service';

// within providers array
providers: [{ provide: HTTP_INTERCEPTORS, useClass: CustomInterceptor, multi: true }]

Answer 11

Answer №6

Prevent browser cache using meta tags in HTML:

<meta http-equiv="cache-control" content="no-cache, must-revalidate, post-check=0, pre-check=0">
<meta http-equiv="expires" content="0">
<meta http-equiv="pragma" content="no-cache">

Answer 12

Prevent browser cache using meta tags in HTML:

<meta http-equiv="cache-control" content="no-cache, must-revalidate, post-check=0, pre-check=0">
<meta http-equiv="expires" content="0">
<meta http-equiv="pragma" content="no-cache">

Answer 13

Answer №7

Although I may be a bit tardy to the party, I encountered a similar issue recently with Angular 4.X. To combat caching by IE, I took matters into my own hands and crafted a custom Http class that appends a random number to the end of requests. This approach was inspired by the insights shared in the second link provided by dimeros (What is httpinterceptor equivalent in angular2?). Keep in mind that this solution comes with a caveat: it's not foolproof and may still contain bugs.

import { Injectable } from '@angular/core';
import { Observable } from 'rxjs/Observable';
import { Http, Response, XHRBackend, RequestOptions, RequestOptionsArgs, 
URLSearchParams } from '@angular/http';

@Injectable()
export class NoCacheHttp extends Http {
    constructor(backend: XHRBackend, options: RequestOptions) {
        super(backend, options);
    }

    get(url: string, options?: RequestOptionsArgs): Observable<Response> {
        // Create options object if none exists.
        if (!options) {
            options = { params: new URLSearchParams() };
        }
        // Append a random number to query parameters to prevent browser caching.
        // Handle different types of params: string, URLSearchParams, plain object.
        if (typeof options.params === 'string') {
            let params = new URLSearchParams(options.params);
            params.set("k", new Date().getTime().toString());
            options.params = params;
        } else if (options.params instanceof URLSearchParams) {
            let params = <URLSearchParams>options.params;
            params.set("k", new Date().getTime().toString());
        } else {
            let params = options.params;
            params["k"] = new Date().getTime().toString();
        }
        return super.get(url, options);
    }
}

Answer 14

Although I may be a bit tardy to the party, I encountered a similar issue recently with Angular 4.X. To combat caching by IE, I took matters into my own hands and crafted a custom Http class that appends a random number to the end of requests. This approach was inspired by the insights shared in the second link provided by dimeros (What is httpinterceptor equivalent in angular2?). Keep in mind that this solution comes with a caveat: it's not foolproof and may still contain bugs.

import { Injectable } from '@angular/core';
import { Observable } from 'rxjs/Observable';
import { Http, Response, XHRBackend, RequestOptions, RequestOptionsArgs, 
URLSearchParams } from '@angular/http';

@Injectable()
export class NoCacheHttp extends Http {
    constructor(backend: XHRBackend, options: RequestOptions) {
        super(backend, options);
    }

    get(url: string, options?: RequestOptionsArgs): Observable<Response> {
        // Create options object if none exists.
        if (!options) {
            options = { params: new URLSearchParams() };
        }
        // Append a random number to query parameters to prevent browser caching.
        // Handle different types of params: string, URLSearchParams, plain object.
        if (typeof options.params === 'string') {
            let params = new URLSearchParams(options.params);
            params.set("k", new Date().getTime().toString());
            options.params = params;
        } else if (options.params instanceof URLSearchParams) {
            let params = <URLSearchParams>options.params;
            params.set("k", new Date().getTime().toString());
        } else {
            let params = options.params;
            params["k"] = new Date().getTime().toString();
        }
        return super.get(url, options);
    }
}

Avoiding caching of GET requests in Angular 2 for Internet Explorer 11

Answer №1

Answer №2

Answer №3

Answer №4

Answer №5

Answer №6

Prevent browser cache using meta tags in HTML:

Answer №7

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