Hello! Today we want to talk about the history in HTTP headers. You might be wondering what HTTP headers are and why their history is important. HTTP headers contain information about requests and responses between websites and are one of the most important pieces of information that exist in these headers. When we want to understand a response that has been sent or whether a specific source is still valid or not, the history plays a significant role.
In fact, the history in HTTP headers is divided into two main categories: the date and time of the response and the date and time of validity. The header Last-Modified indicates when a specific source was last modified, and the header Date shows the current time of the server. This information helps browsers or clients determine whether to re-fetch resources or not, and thus helps optimize web page loading.
Now, let's review some HTTP headers that include dates. The most important headers related to time are Date and Last-Modified. When you send an HTTP request to a server, these headers are part of the response payload. For example, if you request an image from a website, the last-modified date can help you understand whether this image is fresh or if you've seen it before.
In summary, this information in headers not only helps users but also assists developers in auditing their websites and optimizing them. For this reason, the history in HTTP headers is essential for every web master and must be given significant attention: content validity and management.
Date: Mon, 20 Mar 2023 14:28:53 GMT.
Last-Modified: Tue, 15 Mar 2023 10:00:00 GMT.
Code Explanation
In the example above, we see two important HTTP headers:
- Date:
Date: Mon, 20 Mar 2023 14:28:53 GMTindicating the time the response was received from the server. - Last Modified:
Last-Modified: Tue, 15 Mar 2023 10:00:00 GMTwhich indicates the last time this source was modified at the specified date.