How to set the 304 status code? Operation steps and precautions

in the process of website operation and maintenance and optimization, HTTP status code is an important communication language connecting server and browser, among which 304 status code plays a key role in optimizing resource loading and reducing server pressure. Although many webmasters know that it can improve website performance, they have little knowledge of specific setting methods and operation details. This article will start with the principle of 304 status code, gradually explain the setting steps of different servers, and at the same time sort out the core precautions when setting, help operation and maintenance personnel to accurately configure and realize the efficient use of website resources.

What is the 304 status code?

to set the 304 status code correctly, we must first clarify its definition and core value, so as to understand the meaning of the setting.

1, 304 status code basic definition

304 status code belongs to a kind of HTTP 3xx redirect status code, which stands for "unmodified". When the browser requests the cached resource again, it will send the resource identifier of the local cache to the server. After the server compares and finds that the resource has not been updated, it will return 304 status code, telling the browser to use the local cache directly, and there is no need to download the resource again.

2, the core role of 304 status code

first, 304 status code can greatly reduce the bandwidth consumption and load pressure of the server, because there is no need to repeat the transmission of unmodified static resources; secondly, it can shorten the resource loading time of the browser and improve the user's page access speed and experience; finally, it has a positive impact on the website SEO, faster loading speed can indirectly improve the search ranking performance of the page.

How to set 304 status code for different servers?

different types of servers, there are differences in the setting method of 304 status code. The following are the specific operation steps for the commonly used Apache, Nginx and IIS servers.

1, Apache server set 304 status code

Apache server mainly realizes the setting of 304 status code by modifying the .htaccess configuration file. First find the .htaccess file in the root directory of the website, and create a new one if not; then add caching rules to the file, set the expiration time for static resources such as pictures, CSS, and JS, and turn on the ETag logo. ETag is the unique logo generated by the server for resources, which is used to compare whether the resources are modified. For example, add "ExpiresActive On" to turn on the expiration control, and "ExpiresByType image/jpeg" access plus 1 "month" to set the cache period of 1 month for the JPG image, so that the verification logic of the 304 status code will be triggered when the browser requests again.

2, Nginx server set 304 status code

Nginx server sets the 304 status code by modifying the nginx.conf configuration file. In the corresponding server block, add the location module to match static resources, set the expires instruction to define the cache expiration time, and turn on the etag on instruction to enable identity verification. For example, set "expires 1d;" for CSS and JS files, that is, a cache period of 1 day, the server will automatically generate an ETag for these resources. When the browser requests again, it will return the 304 status code after comparing the resource identity. After the configuration is completed, you need to restart the Nginx service to make the setting take effect.

3, IIS server set 304 status code

IIS the settings of the server are relatively visual, open the IIS manager, find the corresponding website and enter the "HTTP response header" setting interface, click "Set common headers", tick "Enable content expiration", then select "Expire after this time" and set the specific expiration time, such as 7 days. At the same time, IIS will automatically enable the ETag function by default, no additional configuration is required, and save it after completing the settings to realize the trigger logic of the 304 status code.

3. What are the precautions for setting the 304 status code?

304 status code seems simple, but if you ignore the details, it may cause problems such as resource cache exceptions, so you need to pay attention to these precautions.

1, reasonably set the cache expiration time

set the 304 status code, the choice of cache expiration time is particularly critical. For resources with very low update frequency, such as website logos and fixed background images, a long expiration time can be set, such as 1-3 months; for resources with medium update frequency, such as CSS and JS files, an expiration time of 1-7 days can be set; for dynamic content that is frequently updated, it is not suitable to enable the cache rule corresponding to the 304 status code to avoid users seeing expired content.

2, make sure the ETag works with Last-Modified

ETag and Last-Modified are the two core identifiers for the server to determine whether the resource is modified. Last-Modified records the last modification time of the resource, and ETag is the unique hash value of the resource. When setting the 304 status code, it is recommended to enable these two identifiers at the same time. When there is an error in the time judgment of Last-Modified, ETag can be used as a supplement to improve the accuracy of resource verification and avoid cache failure or misjudgment.

3, avoid false triggering and missed triggering of 304 status code

setting is completed, it should be tested to avoid false triggering or missed triggering of the 304 status code. For example, when the resource has been updated, make sure that the server can return the 200 status code correctly and let the browser download the new resource again; when the resource is not updated, make sure that the server can return the 304 status code stably to avoid repeated transmission of resources. You can check the status code of the network request through the browser's developer tools to verify whether the configuration is effective.

To sum up, 304 status code is an important tool for website resource optimization, from understanding its principle of action, to completing specific settings according to different server types, and then to avoiding the core risks in the setting, each step directly affects the performance of the website. Reasonable configuration of 304 status code can not only reduce the load of the server, but also improve the user access experience. It is a key link in the process of website operation and maintenance and optimization that cannot be ignored. Webmasters need to combine the resource characteristics of their own websites, accurately adjust the configuration details, and achieve efficient use of resources.