Nextjs Set Hostname and Enable Custom Domains

Let's dive into setting a hostname and enabling custom domains in Next.js.

You can set a hostname in your `next.config.js` file by adding a `hostname` property to the exported object. This is useful for testing purposes or for setting up a staging environment.

Setting a hostname allows you to access your application at the specified hostname, making it easier to test and debug.

For example, if you set the hostname to `staging.example.com`, you can access your application at `http://staging.example.com:3000`.

The Pages Router was the default way to route requests in Next.js until version 13, when they introduced the App Router.

To handle custom domains with the Pages Router, you can use server-side functions in App Pages to render based on the custom domain.

If your app uses the App Router, you can run server-side code in your components, which allows you to check request details at the component level.

This is especially useful for conditional rendering based on the request domain, especially when coupled with authentication.

Pre-rendering pages with custom domains is possible, but it can be a complex process that requires significant reimagining of your app architecture.

You can fetch the list of all custom domains, create a specific .env for each, run npm run build, and deploy the static output, but this process needs to be repeated for each client and whenever new custom domains are added.

With the App Router, you can also run server-side code in your components, making it easier to handle custom domains with little to no app modification required.

You can run server-side code in your components using the app router, allowing you to check request details at the component level.

This is especially useful for conditional rendering based on the request domain, which can be a game-changer for authentication.

To take it a step further, API routes can perform similar functions to middleware, using the domain from the header in the rest of your code.

For example, you can use an API route to potentially do something different when a custom domain is detected, giving you more flexibility in your Next.js setup.

API routes can perform similar functions to middleware, using the domain from the header in the rest of your code. This is especially useful for custom domains, as it allows for conditional rendering based on the request domain.

API routes can do something different when a custom domain is detected, making them a great option for handling custom domains. This is shown in an example where an API route is used to potentially do something different based on the domain.

API routes can be used to capture requests before they reach your page, preparing requests or performing redirects. This is similar to middleware, but with a more flexible approach.

Client-Side Pages can handle domain information using window.location.hostname or window.location.host. This is useful for small template changes or calling an API to get data or content for a specific custom domain.

To get the current domain and do something different, you can use window.location.hostname. For example, if you're loading data or content from an API after an initial client-side render, based on the custom domain, you can use this method.

Client-side pages can also handle domain information using a state callback wrapped around window.location.hostname or window.location.host. However, note that this can be easily spoofed, so don't rely on this alone for authentication or authorization.

You can use the window.location.hostname on the client side to do something different when you detect a custom domain. This can be useful for loading data or content from an API after an initial client-side render.