shiggy.sh

#!/bin/bash

# SPDX-FileCopyrightText: 2023 Linnea Gräf <nea@nea.moe>
#
# SPDX-License-Identifier: MIT

set -ueo pipefail
shopt -s extglob
function dbg() {
	echo "$@" >&2
}
self="$0"
read -r method path http

source_ip=unknown
while read -r line; do
	line=$(echo -n "$line" | xargs)
	if [[ -z "$line" ]]; then
		break
	fi
	IFS=: read -r key value <<<"$line"
	if [[ "${key,,}" = "x-forwarded-for" ]]; then
		source_ip="$value"
	fi
done
dbg --------------
dbg Method: $method
dbg Path: $path
dbg Version: $http
cat >/dev/null &

function begin_response() {
	echo HTTP/1.1 "$1" "$2"
	echo Connection: close
	echo Server: shiggy.sh
	echo Date: $(date +"%a, %d %m %y %H:%M:%S %Z")
}

function content_type() {
	echo "Content-Type: $1"
}

function content_length() {
	echo "Content-Length: $1"
}

function end_headers() {
	echo
}

function resolve_file() {
	echo "$(dirname "$self")/$1"
}

function send_file() {
	filename="$(resolve_file "$1")"
	content_length $(wc -c "$filename" | cut -d ' ' -f 1)
	end_headers
	cat <"$filename"
}

function send_heredoc() {
	data="$(cat)"
	content_length ${#data}
	end_headers
	echo -n "$data"
}

function send_file_if_exists() {
	if [[ -f "$(resolve_file "$1")" ]]; then
		begin_response 200 Found
		content_type "$2"
		send_file "$1"
	else
		send_404
	fi
}

function send_404() {
	dbg 404 hit by $source_ip
	begin_response 404 "Not Found"
	content_type "text/html"
	send_heredoc <<-'EOF'
		<html>
		<head>
		    <title>404 Not Found</title>
		</head>
		<body>
		<div class="center">
		    <h1 color=red>404 Not Found</h1>
		    <img src="/404.png" alt="4OwO4 nyot found :3"/>
		</div>
		</body>
		</html>
	EOF
}

function random_shiggy() {
	ls -1 posts | shuf -n 1
}

function redirect_to() {
	begin_response 302 "Redirect"
	echo "Location: $1"
	end_headers
}
function get_random_fragment() {
	get_fragment $(random_shiggy)
}
function get_fragment() {
	cat <<EOF
<div class="shiggy">
<img src="/image/$1" />
<a href="/image/$1">Permalink</a>
<a href="/report/$1" class="report">Report</a>
<a href="#" onclick="window.location.reload()">Another one</a>
</div>
EOF
}

case "$path" in
/)
	begin_response 200 Found
	content_type text/html
	send_heredoc <<-EOF
		<html>
		<head>
		<title>Shiggy</title>
		<link rel="stylesheet" href="/style.css">
		</head>
		<body>
		<div class="center">
		$(get_random_fragment)
		</div>
		</body>
		</html>
	EOF
	;;
/report/*)
	shiggy_id="${path:8}"
	if [[ -f "posts/$shiggy_id" ]] && [[ ${REPORT_WEBHOOK-missing} != missing ]]; then
		structure='
        {
            "embeds": [
            {
                "color": 14960972,
                "title": "New report",
                "description": $report,
                "author": {
                "name": $ip
            },
            "image": {
            "url": "attachment://SPOILER_shiggy.png"
        }
    }
    ],
    "attachments": [
    ],
    "allowed_mentions": {"parse":[]}
}
'
		json="$(jq -n --arg report "Shiggy # $shiggy_id has been reported" --arg ip "$source_ip" "$structure")"
		curl $REPORT_WEBHOOK -X POST -H "Content-Type: multipart/form-data" -F "payload_json=$json" -F'files[0]=@'"posts/$shiggy_id;filename=SPOILER_shiggy.png" >&2
		begin_response 200 Found
		content_type text/html
		send_heredoc <<EOF
<html>
<head>
<title>Thank you for your report</title>
</head>
<body>
<div class="center">
Thank you for reporting Shiggy # ${shiggy_id}
</div>
</body>
</html>
EOF
	else
		send_404
	fi
	;;
/style.css)
	begin_response 200 Found
	content_type text/css
	send_heredoc <<EOF
.center {
    display: grid;
    justify-content: center;
}
img {
    display: block;
}
a {
    display: block;
    text-align: center;
}
EOF
	;;
/image/random)
	redirect_to /image/"$(random_shiggy)"
	;;
/image/*[!0123456789]*.png)
	send_404
	;;
/image/*.png)
	send_file_if_exists "posts/${path:7}" image/png
	;;
/404.png)
	begin_response 200 "Found"
	content_type image/png
	send_file 404.png
	;;
*)
	send_404
	;;
esac