Caddy server recipes

Unless indicated otherwise, these recipes are for the Caddy web server version 2.

Contents

Multiple sites in separate files (Caddyfile.d)

Create a Caddyfile consisting of the following single line:

import Caddyfile.d/*.conf

Create the directory Caddyfile.d/ next to the Caddyfile. Put your site configurations in Caddyfiles with the extension .conf in Caddyfile.d/. Note that with this setup one broken Caddyfile will prevent your server from starting.

Overriding an error status code

Use the respond or the file_server directive in the error handler.

handle_errors {
    file_server {
        status 200
    }
    rewrite * /templates/index.html
}

Redirecting a query parameter to a path

This will only work with a single query parameter. The example is something useful for the Fossil SCM wiki. It prevents search engines and users from accessing your pages as both /wiki?name=foo and /wiki/foo. (The latter seems more search engine-friendly.)

@wiki_query {
    path_regexp ^/wiki(?:/*|)$
    query name=*
}
route @wiki_query {
    uri replace name= /
    redir * /wiki{query}
}

Reverse proxy for...

Everything except some static files

root * /opt/foo/static
@not_static {
    not {
        path /BingSiteAuth.xml /robots.txt  
        path /favicon.ico
    }
}
reverse_proxy @not_static localhost:8100
file_server

Generic non-PHP FastCGI

reverse_proxy /path* {
    to localhost:9000
    transport fastcgi
}

SCGI

You can use the unofficial third-party scgi-transport module.

reverse_proxy /path* {
    to localhost:9999 
    transport scgi
}

WeeChat

See the Glowing Bear wiki page Proxying WeeChat relay with a web server.

weechat.example.com {
    reverse_proxy /weechat localhost:9001
}

Running CGI scripts

Caddy can run CGI script either with a plugin or with a FastCGI-to-CGI proxy. See my caddy-cgi repository.

Serving Markdown files as pages

You can serve Markdown files as adequately good-looking minimal web pages. See my caddy-markdown-site repository.

Showing an error page on errors

This will give your server a human-readable, if not the most user-friendly, error page. It will tell the user an error has occurred and give them something to report to you. The page will contain a custom error message for the most common errors: 403, 404, 500. Otherwise the error message will be the description text of the HTTP status code.

Caddyfile

handle_errors {
    rewrite * /error.html

    file_server
    templates
}

error.html

<!DOCTYPE html>
{{ $code := placeholder "http.error.status_code" }}
{{ $text := placeholder "http.error.status_text" }}
<html>
<head>
    <title>{{ $code }} {{ $text }}</title>
</head>
<body>
    <h1>Error {{ $code }}</h1>
    {{ if eq $code "403" }}
        <p>You don’t have permission to access this resource.</p>
    {{ else if eq $code "404" }}
        <p>The requested URL was not found on this server.</p>
    {{ else if eq $code "500" }}
        <p>An internal server error has occurred.</p>
    {{ else }}
        <p>{{ $text }}.</p>
    {{ end }}
</body>
</html>

Tags: configuration, how-to, Internet, sysadmin, webdev.