Skip to main content

How Response Caching Works In Asp.Net Core


What Is Response Caching?:

Response Caching means storing of response output and using stored response until it's under it's the expiration time. Response Caching approach cuts down some requests to the server and also reduces some workload on the server.

Response Caching Headers:

Response Caching carried out by the few Http based headers information between client and server.
Main Response Caching Headers are like below
  • Cache-Control
  • Pragma
  • Vary

Cache-Control Header:

Cache-Control header is the main header type for the response caching. Cache-Control will be decorated with the following directives.
  • public - this directive indicates any cache may store the response.
  • private - this directive allows to store response with respect to a single user and can't be stored with shared cache stores.
  • max-age - this directive represents a time to hold a response in the cache.
  • no-cache - this directive represents no storing of response and always fetch the fresh response from server
  • no-store - cache can't store the request or response.

Pragma Header:

Pragma Header used for Http/1.0 request with no-cache directive value. Pragma gets ignored if response decorated with Cache-Control

Vary Header:

Vary Header fields must match with the original request-response and the new request.

ResponseCache Attribute:

Asp.Net Core provided ResponseCache Attribute to enable response cache on MVC/Web API/Razor Pages. This attribute needs to be populated with respective input parameters to generate the cache headers. The following are few input parameters for the cache attribute.
  • Duration - Gets or sets the duration in seconds for which response is cached. This sets "max-age" in "cache-control" header.
  • Location - Gets or sets the location where the data from a particular URL must be cached. It accepts three types of parameters. If Location decorated with "ResponsCacheLocation.Any" works like response cached in both proxies and client and sets "cache-control" header to the public. If Location decorated with "ResponseCacheLocation.Client" works like response cached only in the client and sets "cache-control" header to private. if Location decorated with "ResponseCacheLocation.None" works like "cache-control" and "Pragma" headers set to "no-cache".
  • NoStore - Gets or sets the value which determines whether the data should store or not. When NoStore decorates with 'true' value, it sets the "cache-control" header to "no-store" and ignores the "Location" parameter for values other than "None" and ignores "Duration" as well.
  • VaryByHeader - Gets or sets the value for the "Vary" response header.
  • VaryByQueryKeys - Gets or sets the query keys to "Vary".
Let's start testing the response cache on MVC endpoint using ResponseCache Attribute as below.
HomeController.cs:
[ResponseCache(Duration =120, Location = ResponseCacheLocation.Any, NoStore = false)]
public IActionResult Index()
{
 return View();
}
Above controller decorated with ResponseCache Attribute. Cache duration set to 120 secs, Location set to ResponseCache.Any which results in "public" value for the "cache-control" header.
Now run the application and open developer console and then check cache headers are added to response headers as below.
Now from the picture above "max-age=120" means the browser after receiving the first request with "cache-control" header value with "public" stores the data for 120 secs. So from the next request of the same page from the website will be loads from the disk cache as shown below
After clicking on the home page link from the website as shown in the above picture, we can observe page gets reloaded from the cache as below.
While Testing response caching always click on links within the websites because clicking Href on the website browser will check the previous response headers if they are cached so it will load the page from the cache if headers matched. If we reload the page or clicking the enter button browser search bar browser will request the page from the server.
Now update the ResponseCache Attribute location parameter with a value "ResponseCache.Client" as below 
[ResponseCache(Duration =120, Location = ResponseCacheLocation.Client, NoStore = false)]
Now observe the response header where the "cache-control" value set to "private" as below.
Now update the ResponseCache Attribute location parameter with a value "ResponseCache.None" as below. 
[ResponseCache(Duration =120, Location = ResponseCacheLocation.None, NoStore = false)]
Now observe the response header where the "cache-control" value set to "no-cache" as below.
Now update the ResponseCache Attribute "NoStore" parameter with a value "true". By setting "true" to "NoStore" will override the "cache-control" value of the "Location " parameter as below. 
[ResponseCache(Duration =120, Location = ResponseCacheLocation.Any, NoStore = true)]
Now observe the response header where the "cache-control" value set to  "no-store" as below.

public vs private vs no-cache values of cache-control:

What is a proxy server? - Internet Service Providers may maintain some multiple numbers of proxy servers were to maintain and cache the data to fastly serve the information to their customers.
  • cache-control: public - caching of response both in proxy servers and in client machines(browser).
  • cache-control: private - caching of response only in the client machine.
  • cache-control: no-cache - no caching, every request will be freshly fetched from the server.

VaryByHeader In ResponseCache Attribute:

VaryByHeader in Asp.Net Core represents the Http "Vary" Header. The "Vary" header uses the current request-response header value to be matched with future request header. If headers match future request-response fetch from the cache and if not match fetch response freshly from the server.

The best example to test Http "Vary" Header by populating it with "User-Agent". "User-agent" gives information like the type of client request to the server. In general "User-Agent" will be different for the device to device.

Example of how User-Agent works with response caching?
  • In a website configure home page by enabling response cache attribute with "VaryByHeader" value set to "User-Agent". 
  • Now from desktop access, the home page will be rendered with response header with "Vary". After that click on the home page link to refresh the page since "User-Agent" cache enabled and headers match response will be loaded from the cache. 
  • Now open developers' tools and select the setting to mobile device options and then click on the home page link on the website. Now the device type is changed so the "User-Agent" value will be changed so now the browser will send a fresh request to the server instead of loading a response from the cache.
Now let's do VaryByHeader practically. Update the ResponseCache Attribute "VarByHeader" parameter with the value "User-Agent" as below. 
[ResponseCache(Duration =120,VaryByHeader = "User-Agent", Location = ResponseCacheLocation.Any, NoStore = false)]
Now run the application in desktop mode and the "Vary" response header will have value as "User-Agent" as below.
Request User-Agent looks as below.
Now click refresh the page by clicking the home link on the website in desktop device mode. Since user-agent won't change response will be rendered from the cache as below
Now from the developers' tool change settings to mobile devices and click on the home page link. Since device mode changed "User-agent" value will be changed, so browser request data from the server instead of cache as below.
We can observe user agent value will be changed as below.

Cache Profile:

ResponseCache Attribute input parameters may be the same for almost all the action methods in an application. Asp.Net Core provides options like profile cache where all the parameter options are configured startup class with a name to that configuration, that profile name can be used inside the ResponseCache Attribute which removes duplication parameters setting in it.
public void ConfigureServices(IServiceCollection services)
{
 services.AddControllersWithViews(options => {
  options.CacheProfiles.Add("Profile1", new Microsoft.AspNetCore.Mvc.CacheProfile
  {
   Duration = 120,
   Location = Microsoft.AspNetCore.Mvc.ResponseCacheLocation.Any,
   NoStore = false
  });
  options.CacheProfiles.Add("Profile2", new Microsoft.AspNetCore.Mvc.CacheProfile
  {
   VaryByHeader = "User-Agent",
   Duration = 60,
   Location = Microsoft.AspNetCore.Mvc.ResponseCacheLocation.Client,
   NoStore = false
  });
 });
}
Here we have two different cache profiles with their respective settings. We can observe all the parameters we generally configured in ResponseCache Attribute are configured here inside the CacheProfile object."Profile2" cache settings represent caching based on VaryByHeader.

Now update the ResponseCache Attributes with its respective profile names as below. 
[ResponseCache(CacheProfileName ="Profile1")]
public IActionResult Index()
{
 return View();
}

[ResponseCache(CacheProfileName = "Profile2")]
public IActionResult Test()
{
 return View();
}

Custom Middleware To Add Cache:

We can add response cache by writing middleware but this implementation by default adds response cache to any page on the application.
Startup.cs:
app.Use(async (context, next) =>
{
 context.Response.GetTypedHeaders().CacheControl =
  new Microsoft.Net.Http.Headers.CacheControlHeaderValue()
  {
   Public = true,
   MaxAge = TimeSpan.FromSeconds(60),
  };
 await next();
});
Here we can observe on every request, response context adding "CacheControl" object.
HomeController.cs: 
public IActionResult Index()
{
  return View();
}

Combination Of Custom Cache Middleware And ResponseCache Attribute:

Yes, we can use both of them in our Asp.Net Core applications. But ResponseCache Attribute settings override the middleware settings. So it will help like globally every page will have cache information from the custom middleware and if we want to override those settings to any of the endpoint then we can easily override by implementing ResponseCache Attribute on the particular action method.
For example "MaxAge" set to 180 secs on custom middleware and if we configure ResponseCache Attribute with "Duration" set to 60 secs then a response will be cached for 60secs only.

Support Me!
Buy Me A Coffee PayPal Me 

Wrapping Up:

Hopefully, this article will help to understand Response Cache implementation in the Dotnet core. I will love to have your feedback, suggestions, and better techniques in the comments section.

Refer:

Follow Me:

Labels:

Comments

Post a Comment

Popular posts from this blog

Angular 14 Reactive Forms Example

In this article, we will explore the Angular(14) reactive forms with an example. Reactive Forms: Angular reactive forms support model-driven techniques to handle the form's input values. The reactive forms state is immutable, any form filed change creates a new state for the form. Reactive forms are built around observable streams, where form inputs and values are provided as streams of input values, which can be accessed synchronously. Some key notations that involve in reactive forms are like: FormControl - each input element in the form is 'FormControl'. The 'FormControl' tracks the value and validation status of form fields. FormGroup - Track the value and validate the state of the group of 'FormControl'. FormBuilder - Angular service which can be used to create the 'FormGroup' or FormControl instance quickly. Form Array - That can hold infinite form control, this helps to create dynamic forms. Create An Angular(14) Application: Let'
3 comments
Read more

.NET 7 Web API CRUD Using Entity Framework Core

In this article, we are going to implement a sample .NET 7 Web API CRUD using the Entity Framework Core. Web API: Web API is a framework for building HTTP services that can be accessed from any client like browser, mobile devices, and desktop apps. In simple terminology API(Application Programming Interface) means an interface module that contains programming functions that can be requested via HTTP calls either to fetch or update data for their respective clients. Some of the Key Characteristics of API: Supports HTTP verbs like 'GET', 'POST', 'PUT', 'DELETE', etc. Supports default responses like 'XML' and 'JSON'. Also can define custom responses. Supports self-hosting or individual hosting, so that all different kinds of apps can consume it. Authentication and Authorization are easy to implement. The ideal platform to build the REST full services. Install The SQL Server And SQL Management Studio: Let's install the SQL server on our l
3 comments
Read more

ReactJS(v18) JWT Authentication Using HTTP Only Cookie

In this article, we will implement the ReactJS application authentication using the HTTP-only cookie. HTTP Only Cookie: In a SPA(Single Page Application) Authentication JWT token either can be stored in browser 'LocalStorage' or in 'Cookie'. Storing the JWT token inside of the cookie then the cookie should be HTTP Only. The HTTP-ONly cookie nature is that it will be only accessible by the server application. Client apps like javascript-based apps can't access the HTTP-Only cookie. So if we use the authentication with HTTP-only JWT cookie then we no need to implement the custom logic like adding authorization header or storing token data, etc at our client application. Because once the user authenticated cookie will be automatically sent to the server by the browser on every API call. Authentication API: To authenticate our client application with JWT HTTP-only cookie, I developed a NetJS(which is a node) Mock API. Check the GitHub link and read the document on G
3 comments
Read more

.NET6 Web API CRUD Operation With Entity Framework Core

In this article, we are going to do a small demo on AspNetCore 6 Web API CRUD operations. What Is Web API: Web API is a framework for building HTTP services that can be accessed from any client like browser, mobile devices, desktop apps. In simple terminology API(Application Programming Interface) means an interface module that contains a programming function that can be requested via HTTP calls to save or fetch the data for their respective clients. Some of the key characteristics of API: Supports HTTP verbs like 'GET', 'POST', 'PUT', 'DELETE', etc. Supports default responses like 'XML' and 'JSON'. Also can define custom responses. Supports self-hosting or individual hosting, so that all different kinds of apps can consume it. Authentication and Authorization are easy to implement. The ideal platform to build REST full services. Create A .NET6 Web API Application: Let's create a .Net6 Web API sample application to accomplish our
6 comments
Read more

Angular 14 State Management CRUD Example With NgRx(14)

In this article, we are going to implement the Angular(14) state management CRUD example with NgRx(14) NgRx Store For State Management: In an angular application to share consistent data between multiple components, we use NgRx state management. Using NgRx state helps to avoid unwanted API calls, easy to maintain consistent data, etc. The main building blocks for the NgRx store are: Actions - NgRx actions represents event to trigger the reducers to save the data into the stores. Reducer - Reducer's pure function, which is used to create a new state on data change. Store - The store is the model or entity that holds the data. Selector - Selector to fetch the slices of data from the store to angular components. Effects - Effects deals with external network calls like API. The effect gets executed based the action performed Ngrx State Management flow: The angular component needs data for binding.  So angular component calls an action that is responsible for invoking the API call.  Aft
8 comments
Read more

Angular 14 Crud Example

In this article, we will implement CRUD operation in the Angular 14 application. Angular: Angular is a framework that can be used to build a single-page application. Angular applications are built with components that make our code simple and clean. Angular components compose of 3 files like TypeScript File(*.ts), Html File(*.html), CSS File(*.cs) Components typescript file and HTML file support 2-way binding which means data flow is bi-directional Component typescript file listens for all HTML events from the HTML file. Create Angular(14) Application: Let's create an Angular(14) application to begin our sample. Make sure to install the Angular CLI tool into our local machine because it provides easy CLI commands to play with the angular application. Command To Install Angular CLI npm install -g @angular/cli Run the below command to create the angular application. Command To Create Angular Application ng new name_of_your_app Note: While creating the app, you will see a noti
5 comments
Read more

Unit Testing Asp.NetCore Web API Using xUnit[.NET6]

In this article, we are going to write test cases to an Asp.NetCore Web API(.NET6) application using the xUnit. xUnit For .NET: The xUnit for .Net is a free, open-source, community-focused unit testing tool for .NET applications. By default .Net also provides a xUnit project template to implement test cases. Unit test cases build upon the 'AAA' formula that means 'Arrange', 'Act' and 'Assert' Arrange - Declaring variables, objects, instantiating mocks, etc. Act - Calling or invoking the method that needs to be tested. Assert - The assert ensures that code behaves as expected means yielding expected output. Create An API And Unit Test Projects: Let's create a .Net6 Web API and xUnit sample applications to accomplish our demo. We can use either Visual Studio 2022 or Visual Studio Code(using .NET CLI commands) to create any.Net6 application. For this demo, I'm using the 'Visual Studio Code'(using the .NET CLI command) editor. Create a fo
7 comments
Read more

Part-1 Angular JWT Authentication Using HTTP Only Cookie[Angular V13]

In this article, we are going to implement a sample angular application authentication using HTTP only cookie that contains a JWT token. HTTP Only JWT Cookie: In a SPA(Single Page Application) Authentication JWT token either can be stored in browser 'LocalStorage' or in 'Cookie'. Storing JWT token inside of the cookie then the cookie should be HTTP Only. The HTTP-Only cookie nature is that it will be only accessible by the server application. Client apps like javascript-based apps can't access the HTTP-Only cookie. So if we use authentication with HTTP only JWT cookie then we no need to implement custom logic like adding authorization header or storing token data, etc at our client application. Because once the user authenticated cookie will be automatically sent to the server by the browser on every API call. Authentication API: To implement JWT cookie authentication we need to set up an API. For that, I had created a mock authentication API(Using the NestJS Se
Post a Comment
Read more

ReactJS(v18) Authentication With JWT AccessToken And Refresh Token

In this article, we are going to do ReactJS(v18) application authentication using the JWT Access Token and Refresh Token. JSON Web Token(JWT): JSON Web Token is a digitally signed and secured token for user validation. The JWT is constructed with 3 important parts: Header Payload Signature Create ReactJS Application: Let's create a ReactJS application to accomplish our demo. npx create-react-app name-of-your-app Configure React Bootstrap Library: Let's install the React Bootstrap library npm install react-bootstrap bootstrap Now add the bootstrap CSS reference in 'index.js'. src/index.js: import 'bootstrap/dist/css/bootstrap.min.css' Create A React Component 'Layout': Let's add a React component like 'Layout' in 'components/shared' folders(new folders). src/components/shared/Layout.js: import Navbar from "react-bootstrap/Navbar"; import { Container } from "react-bootstrap"; import Nav from "react-boot
Post a Comment
Read more

A Small Guide On NestJS Queues

NestJS Application Queues helps to deal with application scaling and performance challenges. When To Use Queues?: API request that mostly involves in time taking operations like CPU bound operation, doing them synchronously which will result in thread blocking. So to avoid these issues, it is an appropriate way to make the CPU-bound operation separate background job.  In nestjs one of the best solutions for these kinds of tasks is to implement the Queues. For queueing mechanism in the nestjs application most recommended library is '@nestjs/bull'(Bull is nodejs queue library). The 'Bull' depends on Redis cache for data storage like a job. So in this queueing technique, we will create services like 'Producer' and 'Consumer'. The 'Producer' is used to push our jobs into the Redis stores. The consumer will read those jobs(eg: CPU Bound Operations) and process them. So by using this queues technique user requests processed very fastly because actually
8 comments
Read more