PlugCanonicalHost
=================
[](https://travis-ci.org/remiprev/plug_canonical_host)
[](https://hex.pm/packages/plug_canonical_host)
`PlugCanonicalHost` ensures that all requests are served by a single canonical
host. It will redirect all requests from non-canonical hosts to the canonical
one.
Installation
------------
Add `plug_canonical_host` to the `deps` function in your project's `mix.exs` file:
```elixir
defp deps do
[
…,
{:plug_canonical_host, "~> 0.3"}
]
end
```
Then run `mix do deps.get, deps.compile` inside your project's directory.
Usage
-----
`PlugCanonicalHost` can be used just as any other plugs. Add `PlugCanonicalHost`
before all of the other plugs you want to happen after successful redirection
to your canonical host.
The recommended way to define a canonical host is with an environment variable.
```elixir
# config/config.ex
config :my_app,
canonical_host: System.get_env("CANONICAL_HOST")
# lib/my_app/endpoint.ex
defmodule MyApp.Endpoint do
plug(:canonical_host)
defp canonical_host(conn, _opts) do
:my_app
|> Application.get_env(:canonical_host)
|> case do
host when is_binary(host) ->
opts = PlugCanonicalHost.init(canonical_host: host)
PlugCanonicalHost.call(conn, opts)
_ ->
conn
end
end
end
```
For example, if your application is accessible via both `example.com` and
`www.example.com`, all traffic coming through `example.com` will be redirected
(with a `301` HTTP status) to the matching `wwww.example.com` URL.
```bash
$ curl -sI "http://example.com/foo?bar=1"
#> HTTP/1.1 301 Moved Permanently
#> Location: http://www.example.com/foo?bar=1
```
License
-------
`PlugCanonicalHost` is © 2016-2018 [Rémi Prévost](http://exomel.com) and may be
freely distributed under the [MIT license](https://github.com/remiprev/plug_canonical_host/blob/master/LICENSE.md). See the
`LICENSE.md` file for more information.
