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SSL on localhost with Phoenix Framework

Ossi Hanhinen @ohanhi

February 18, 2016

Read this to

learn how to set up SSL for localhost

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Elixir and Phoenix

Sometimes when developing a backend, you want to use HTTPS even on localhost. I ran into this situation not long ago when I was building a mock service providing OAuth 2.0 authentication.

Here’s how you can enable SSL on Elixir Phoenix in dev mode.

1. Get a certificate

For development purposes, you can generate a self-signed certificate with the following commands:

# generate key
$ openssl genrsa -out localhost.key 2048
# generate cert
$ openssl req -new -x509 -key localhost.key -out localhost.cert -days 3650 -subj /CN=localhost

You can of course also use Letsencrypt for a free signed certificate.

2. Copy the key and cert into your project

Put them in a directory called priv/keys/.

3. Set up the config

In your config/dev.exs file:

config :phoenix_oauth2_mock_server, PhoenixOauth2MockServer.Endpoint,
  http: [port: 4000],
  https: [port: 4443,
          otp_app: :phoenix_oauth2_mock_server,
          keyfile: "priv/keys/localhost.key",
          certfile: "priv/keys/localhost.cert"],
  debug_errors: true,
  code_reloader: true,
  check_origin: false,
  watchers: [node: ["node_modules/brunch/bin/brunch", "watch", "--stdin"]]

Done!