Fourohfourfound

Fourohfourfound is an HTTP server intended to be used as a fallback server for 404 errors in the upstream server.

Currently, it allows you to specify a list of redirections.

nginx

Some HTTP servers, such as nginx, require a configuration file change to update the rewrite list. If updating configuration frequently isn't desirable or possible, you can configure nginx to proxy requests to fourohfourfound if it would otherwise return a 404.

location / {
  ...
  error_page 404 = @fourohfourfound;
}
location @fourohfourfound {
  proxy_set_header X-Real-IP $remote_addr;
  proxy_pass http://localhost:4404;
}

This assumes fourohfourfound is running on localhost:4404.

Installation

The usual:

$ go get github.com/whee/fourohfourfound

Usage

Create a configuration file in JSON format:

{
  "redirections": {
    "/source": "/destination",
    "/another-source": "/another-destination"
  }
}

Run fourohfourfound:

$ fourohfourfound

Optional arguments are -code=[3xx], -config=[config.json], and -port=[4404].

Redirections can be modified at runtime with PUT/DELETE:

$ curl -X PUT -d "/somewhere-else" http://localhost:4404/new-redir
$ curl http://localhost:4404/new-redir
<a href="/somewhere-else">Found</a>.

$ curl -X DELETE http://localhost:4404/new-redir
$ curl http://localhost:4404/new-redir
404 page not found

These are not yet persistent. You can retrieve the current configuration, suitable for saving to a file:

$ curl http://localhost:4404/_config
{
  "redirections": {
    "/source": "/destination",
    "/another-source": "/another-destination"
  }
}

You can also PUT a JSON configuration to /_config:

$ curl -X PUT -d"@config.json" http://localhost:4404/_config
Configuration successfully loaded.

Redirections in the JSON configuration are in addition to those already active. DELETEing /_config will remove all redirections.

Notes

Redirections are basic and not as powerful as nginx's rewrite rules. This will likely change.

Future expansion

• Regular expressions
• Statistics/analytics