API Proxying

Often you’ll be developing your Lustre application alongside a separate backend app. This can cause some problems during development as you’ll typically run into CORS issues when your Lustre app tries to make requests to your backend running on a different port.

To solve this, Lustre’s development server includes support for proxying API requests to another server. This means your application code doesn’t require environment-specific logic to determine where to send API requests to, instead it always hits a path like /api/users and the development server takes care of proxying that request to your backend.

Configuration

To configure the API proxy, you’ll need to add a proxy entry to your gleam.toml file under the tools.lustre.dev section. The most common configuration looks something like this:

[tools.lustre.dev]
proxy = { from = "/api", to = "http://localhost:3000/api" }

In this example, any requests made to paths starting with /api will be forwarded to http://localhost:3000/api. So a request to /api/users would be proxied to http://localhost:3000/api/users.

You can also proxy multiple paths to different endpoints in your backend, or even different servers if you need to:

[tools.lustre.dev]
proxy = [{ from = "/api", to = "http://localhost:3000/api" }, { from = "/auth", to = "http://localhost:3000/auth" }]

In this example, requests will be forwarded to the auth or api endpoints depending on the request’s path. :wa