Mastering the HTML caching mechanism is the key to improving web page performance

The key to improving web page performance: Mastering the HTML caching mechanism requires specific code examples

In the Internet era, we increasingly rely on the network to obtain information and complete various tasks. kind of task. Web page performance is one of the important indicators to measure user experience. A webpage that loads slowly can make users feel impatient and even leave the webpage. Therefore, improving web page performance has become a task that front-end developers cannot ignore.

One of the keys to improving web page performance is to master the HTML caching mechanism. The HTML caching mechanism can reduce access to the server, improve the loading speed of web pages, and reduce the burden on the server.

HTML caching mechanisms mainly include two types: browser cache and server cache. The following will introduce these two caching mechanisms respectively, and use specific code examples to help readers better understand.

1. Browser caching

Browser caching refers to saving the static resources of a web page in the user's local browser, and reading them directly from the local the next time they visit the same web page. resources without making any further requests to the server. This can reduce network transfer time and increase web page loading speed.

The implementation of browser caching mainly relies on the Expires and Cache-Control fields in the HTTP response header. The following is a sample code that uses the Expires field to set the cache:

HTTP/1.1 200 OK
Content-Type: text/html
Expires: Wed, 21 Oct 2022 07:28:00 GMT

By setting the Expires field, the browser knows the expiration time of the resource. Before the expiration time, the browser will read the resource directly from the local cache. If the resource needs to be reacquired, the browser will initiate a request to the server, but the server can decide whether to use caching by setting the Cache-Control field in the response header. As shown below:

HTTP/1.1 200 OK
Content-Type: text/html
Cache-Control: public, max-age=3600

Among them, max-age specifies the maximum cache time of the resource, in seconds. The above code indicates that the resource can be cached locally for 3600 seconds, and requests before expiration will not be sent to the server.

2. Server caching

Server caching refers to caching the dynamically generated content of the web page on the server. The next time you access the same content, it will be read directly from the cache without further processing. Complete page rendering, thereby reducing server load and response time.

The specific implementation of server caching depends on the type and configuration of the server. Here, taking the Nginx server as an example, we will introduce how to set up the cache in the server.

First, you need to modify the Nginx configuration file. Find the configuration item of location/{} and add the following code to it:

location / {
    proxy_cache my_cache;
    proxy_cache_valid 200 1h;
    proxy_pass http://backend;
}

In the above code, proxy_cache specifies the cache name, and my_cache indicates that the cache name can be modified according to the actual situation. proxy_cache_valid specifies the cache time of the resource. The above code indicates that the response content of the 200 status code will be cached for 1 hour.

By mastering the HTML caching mechanism and rationally utilizing browser cache and server cache, you can effectively improve the performance of web pages. At the same time, developers also need to consider cache update strategies to avoid cache expiration or dirty data.

Summary:
The key to improving web page performance is to master the HTML caching mechanism. By using browser caching and server caching, network transmission time and server response time can be reduced, and the loading speed of web pages can be improved. The Expires field and Cache-Control field in the code example can help us better understand the implementation of the caching mechanism. At the same time, developers also need to comprehensively consider cache update strategies to ensure the effectiveness of cached content.

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