Trunk 0.5.0 | Proxy System

Build, bundle & ship your Rust WASM application to the web.

• Github repo
• Release notes

Trunk now ships with a built-in proxy which can be enabled when running trunk serve. There are two ways to configure the proxy, each discussed below. All Trunk proxies will transparently pass along the request body, headers, and query parameters to the proxy backend.

proxy cli flags

The trunk serve command accepts two proxy related flags.

--proxy-backend specifies the URL of the backend server to which requests should be proxied. The URI segment of the given URL will be used as the path on the Trunk server to handle proxy requests. E.G., trunk serve --proxy-backend=http://localhost:9000/api/ will proxy any requests received on the path /api/ to the server listening at http://localhost:9000/api/. Further path segments or query parameters will be seamlessly passed along.

--proxy-rewrite specifies an alternative URI on which the Trunk server is to listen for proxy requests. Any requests received on the given URI will be rewritten to match the URI of the proxy backend, effectively stripping the rewrite prefix. E.G., trunk serve --proxy-backend=http://localhost:9000/ --proxy-rewrite=/api/ will proxy any requests received on /api/ over to http://localhost:9000/ with the /api/ prefix stripped from the request, while everything following the /api/ prefix will be left unchanged.

config file

The Trunk.toml config file accepts multiple [[proxy]] sections, which allows for multiple proxies to be configured. Each section requires at least the backend field, and optionally accepts the rewrite field, both corresponding to the --proxy-* CLI flags discussed above.

As it is with other Trunk config, a proxy declared via CLI will take final precedence and will cause any config file proxies to be ignored, even if there are multiple proxies declared in the config file.

The following is a snippet from the Trunk.toml file in this repo:

[[proxy]]
rewrite = "/api/v1/"
backend = "http://localhost:9000/"