api_forward: Set up a plumber2 api to act as a reverse proxy

In plumber2: Easy and Powerful Web Servers

Set up a plumber2 api to act as a reverse proxy

Description

You can set up your plumber2 api to act as reverse proxy and forward all requests to a specific path (and it's subpaths) to a different URL. In contrast to api_shiny(), api_forward() is not responsible for launching whatever service is being proxied so this should be handled elsewhere. The path will be stripped from the request before being forwarded to the url, meaning that if you set up a proxy on ⁠my/proxy/⁠ to ⁠http://example.com⁠, then a request for my/proxy/user/thomas will end at ⁠http://example.com/user/thomas⁠. Proxying is most useful when forwarding to internal servers though you are free to forward to public URLs as well. However, for the later you'd usually use a redirect instead (via api_redirect())

Usage

api_forward(api, path, url, except = NULL, auth_flow = NULL, auth_scope = NULL)

Arguments

api	A plumber2 api to add the shiny app to
path	The path to serve the shiny app from
url	The url to forward to
except	Subpaths to path that should be exempt from forwarding
auth_flow	A logical expression giving the authentication flow the client must pass to get access to the resource.
auth_scope	The scope requirements of the resource

Value

This functions return the api object allowing for easy chaining with the pipe

Using annotation

You can set up a reverse proxy in your annotated route file using the ⁠@forward⁠ tag

#* @forward /proxy http://127.0.0.1:56789
NULL

Examples

# Serve wikipedia directly from your app
api() |>
  api_forward("my_wiki/", "https://www.wikipedia.org")

plumber2 documentation built on Jan. 20, 2026, 5:06 p.m.