PHP server_name vs http_host: Understanding the Differences

Hello Dev, welcome to this article about PHP server_name and http_host! If you’re a web developer or simply interested in website building, you might have come across these two terms before. But do you know what they mean and what sets them apart? If not, don’t worry! In this article, we’ll explore the differences between server_name and http_host and how you can use them in your projects. Let’s get started!

What is server_name?

Before we dive into the differences between server_name and http_host, let’s first take a look at what server_name is. Server_name is a variable that contains the name of the server that the PHP script is running on. It is part of the $_SERVER superglobal array, which contains a wealth of information about the server environment.

The server_name variable is particularly useful for virtual hosting, where multiple domains are hosted on the same server. By using server_name, you can determine which domain the PHP script is running on and take the appropriate actions based on that information. For example, you can use server_name to serve different content or apply different settings depending on the domain name.

Using server_name in virtual hosting

Let’s say you have two domains, example.com and example.net, hosted on the same server. You want to serve different content depending on which domain the user visits. Here’s how you can do this using server_name:

Domain	server_name value
example.com	“example.com”
example.net	“example.net”

You can then use a conditional statement to check the value of server_name and serve the appropriate content:

if ($_SERVER['SERVER_NAME'] == "example.com") {// serve content for example.com} else if ($_SERVER['SERVER_NAME'] == "example.net") {// serve content for example.net}

Using server_name in this way can make your code more flexible and easier to maintain, especially if you have a large number of domains hosted on the same server.

What is http_host?

Now that we know what server_name is, let’s take a look at http_host. Http_host is also a variable that contains the name of the server, but it includes the port number and any additional headers that were sent with the request.

Http_host can be useful in situations where the server_name value is not set correctly or is not available. For example, if you’re running a PHP script behind a load balancer or reverse proxy, the server_name value might not reflect the actual domain name. In this case, you can use http_host to get the correct domain name.

Using http_host to get the correct domain name

Let’s say you have a load balancer that distributes traffic to two servers, server1 and server2. You have two domains, example.com and example.net, that are hosted on server1 and server2 respectively. When a user visits example.com, the load balancer forwards the request to server1 with an X-Forwarded-Host header that contains the value “example.com”. Here’s how you can use http_host to get the correct domain name:

if (isset($_SERVER['HTTP_X_FORWARDED_HOST'])) {// use the value of X-Forwarded-Host$domain = $_SERVER['HTTP_X_FORWARDED_HOST'];} else {// use the value of http_host$domain = $_SERVER['HTTP_HOST'];}if ($domain == "example.com") {// serve content for example.com} else if ($domain == "example.net") {// serve content for example.net}

In this example, we first check if the X-Forwarded-Host header is set, and if so, use its value as the domain name. If the header is not set, we fall back to using http_host. This ensures that we get the correct domain name regardless of whether the server_name value is set correctly.

What are the differences between server_name and http_host?

Now that we’ve looked at what server_name and http_host are, let’s compare them and see what sets them apart:

1. Server_name contains only the name of the server, while http_host includes additional headers and the port number.
2. Server_name is set by the server, while http_host is set by the client.
3. Server_name is used primarily for virtual hosting, while http_host is used for obtaining the correct domain name in various situations.

By understanding these differences, you can choose the appropriate variable for your needs and use it effectively in your projects.

FAQ

Q: Can I use server_name and http_host interchangeably?

A: No, server_name and http_host are not interchangeable. While they both contain the name of the server, they have different purposes and are set by different entities. Using the wrong variable can result in incorrect behavior or security vulnerabilities.

Q: Which variable should I use for virtual hosting?

A: You should use server_name for virtual hosting, as it is specifically designed for this purpose. Http_host might work in some cases, but it includes additional headers and is set by the client, which can lead to security vulnerabilities if not handled correctly.

Q: Which variable should I use behind a load balancer or reverse proxy?

A: You should use http_host to get the correct domain name, as server_name might not reflect the actual domain name in this scenario. However, you should also make sure to handle X-Forwarded headers correctly to prevent security vulnerabilities.

Q: Can I modify the value of server_name or http_host?

A: No, you should not modify the value of server_name or http_host. These variables are set by the server or the client, respectively, and changing their value can result in incorrect behavior or security vulnerabilities.

Q: What other variables are included in the $_SERVER superglobal array?

A: The $_SERVER superglobal array contains a wealth of information about the server environment, including the request method, request URI, HTTP headers, and more. You can use this information to customize your application behavior based on the user’s request.

Conclusion

That’s it for our exploration of server_name vs http_host! We hope this article has helped you understand the differences between these two variables and how you can use them in your projects. Remember to choose the appropriate variable for your needs and use it correctly to ensure the security and reliability of your code. If you have any further questions or comments, feel free to leave them below. Thanks for reading!