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Introduction

HTTP redirection is way to point one domain or address to another. There are a few different kinds of redirects, each of which mean something different to the client browser. The two most common types are temporary redirects and permanent redirects.

Temporary redirects (response status code 302 Found) are useful if a URL temporarily needs to be served from a different location. For example, if you are performing site maintenance, you may wish to use a temporary redirect of from your domain to an explanation page to inform your visitors that you will be back shortly.

Permanent redirects (response status code 301 Moved Permanently), on the other hand, inform the browser that it should forget the old address completely and not attempt to access it anymore. These are useful when your content has been permanently moved to a new location, like when you change domain names.

You can create a temporary redirect in Nginx by adding a line like this to the server block entry in the server configuration file:

rewrite ^/oldlocation$ http://www.newdomain.com/newlocation redirect;

Similarly, use a line like this for a permanent redirect:

rewrite ^/oldlocation$ http://www.newdomain.com/newlocation permanent;

This guide will cover a more in depth explanation of how to implement each kind of redirect in Nginx, and go through some examples for specific use cases.

Solution at a Glance

In Nginx, you can accomplish most redirects with the built-in rewrite directive. This directive is available by default on a fresh Nginx installation and can be used to create both temporary and permanent redirects. In its simplest form, it takes at least two arguments: the old URL and the new URL.

You can implement a temporary redirect with the following lines in your server configuration:

server {
    . . .
    server_name www.domain1.com;
    rewrite ^/$ http://www.domain2.com redirect;
    . . .
}

This redirect instructs the browser to direct all requests for www.domain1.com to www.domain2.com. This solution, however, works only for a single page, not for the entire site. To redirect more than a single page, you can use the rewrite directive with regular expressions to specify entire directories instead of just single files.

redirect matches regular expression patterns in parenthesis. It then references the matched text in the redirect destination using $1 expression, where 1 is the first group of matched text. In more complex examples, subsequent matched groups are given numbers sequentially.

For example, if you wanted to temporarily redirect every page within www.domain1.com to www.domain2.com, you could use the following:

server {
    . . .
    server_name www.domain1.com;
    rewrite ^/(.*)$ http://www.domain2.com/$1 redirect;
    . . .
}

server {
    . . .
    server_name www.domain2.com;
    . . .
}

By default, the rewrite directive establishes a temporary redirect. If you would like to create a permanent redirect, you can do so by replacing redirect with permanent at the end of the directive, like this:

rewrite ^/$ http://www.domain2.com permanent;
rewrite ^/(.*)$ http://www.domain2.com/$1 permanent;

Example 1 — Moving to a Different Domain

If you have established a web presence and would like to change your domain to a new address, it is best not to just abandon your old domain. Bookmarks to your site and links to your site located on other pages throughout the internet will break if your content disappears without any instructions to the browser about how to find its new location. Changing domains without redirecting will cause your site to lose traffic from previous visitors.

In this example, we will configure a redirect from the old domain called domain1.com to the new one called domain2.com. We’ll use permanent redirects here because the old domain will be taken down, and all traffic should go to the new domain from now on.

Let’s assume you have your website configured to be served from a single domain called domain1.com already configured in Nginx as follows:

in /etc/nginx/sites-available/domain1.com:

server {
    . . .
    server_name domain1.com;
    . . .
}

We’ll also assume you are already serving your future version of website at domain2.com:

in /etc/nginx/sites-available/domain2.com:

server {
    . . .
    server_name domain2.com;
    . . .
}

Back to /etc/nginx/sites-available/domain1.com:

server {
    . . .
    server_name domain1.com;
    rewrite ^/(.*)$ http://domain2.com/$1 permanent;
    . . .
}

We’ve added the aforementioned redirect using a rewrite directive. The ^/(.*)$ regular expression matches everything after the / in the URL. For example, http://domain1.com/index.html will get redirected to http://domain2.com/index.html. To achieve the permanent redirect we simply add permanent after the rewrite directive.

Reboot nginx with systemctl restart nginx

Example 2 — Creating a Persistent Experience Despite Single Page Name Changes

Sometimes, it is necessary to change the names of individual pages that have already been published and received traffic on your site. Changing the name alone would cause a 404 Not Found error for visitors trying to access the original URL, but you can avoid this by using a redirect. This makes sure that people who have bookmarked your old pages, or found them through outdated links on search engines, will still reach the correct page.

Let’s imagine your website had two separate pages for products and services called products.html and services.html respectively. Now, you’ve decided to replace those two pages with a single offer page called offers.html instead. We will configure a simple redirect for products.html and services.html to offers.html.

We assume you have your website configured as follows:

server {
    . . .
    server_name example.com www.example.com;
    . . .
}

Configuring the redirects is as simple as using two Redirect directives.

server {
    . . .
    server_name example.com www.example.com;

    rewrite ^/products.html$ /offer.html permanent;
    rewrite ^/services.html$ /offer.html permanent;
    . . .
}

The rewrite directive accepts the original address that has to be redirected as well as the destination address of a new page. Since the change here is not a temporary one, we used permanent in the directive as well. You can use as many redirects like that as you wish to make sure your visitors won’t see unnecessary Not Found errors when moving site contents.

Conclusion

You now have the knowledge to redirect requests to new locations. Be sure to use the correct redirection type, as an improper use of temporary redirects can hurt your search ranking.

There are multiple other uses of HTTP redirects, including forcing secure SSL connections (i.e. using https instead of http) and making sure all visitors will end up only on the www. prefixed address of the website.

 

Original Article by Mateusz Papiernik and edited by the author of this post according to the Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International License.