#!/bin/bash
#######################################################################################################################
# Add Nginx reverse proxy fromt end to default Guacamole install
# For Ubuntu / Debian / Raspbian
# 3 of 4
# David Harrop
# August 2023
#######################################################################################################################

# Prepare text output colours
GREY='\033[0;37m'
DGREY='\033[0;90m'
GREYB='\033[1;37m'
LRED='\033[0;91m'
LGREEN='\033[0;92m'
LYELLOW='\033[0;93m'
NC='\033[0m' #No Colour

echo
echo
echo -e "${LGREEN}Installing Nginx...${DGREY}"
echo

# Install Nginx
sudo apt-get install nginx -qq -y &>>${LOG_LOCATION}

echo -e "${GREY}Configuring Nginx as a reverse proxy for Guacamole's Apache Tomcat front end...${DGREY}"
# Configure /etc/nginx/sites-available/(local dns site name)
cat <<EOF | tee /etc/nginx/sites-available/$PROXY_SITE
server {
    listen 80 default_server;
    root /var/www/html;
    index index.html index.htm index.nginx-debian.html;
    server_name $GUAC_URL;
    location / {
        proxy_pass $GUAC_URL;
        proxy_buffering off;
        proxy_http_version 1.1;
        proxy_set_header X-Forwarded-For \$proxy_add_x_forwarded_for;
        proxy_set_header Upgrade \$http_upgrade;
        proxy_set_header Connection \$http_connection;
        access_log off;
    }
}
EOF
if [ $? -ne 0 ]; then
    echo -e "${LRED}Failed. See ${LOG_LOCATION}${GREY}" 1>&2
    exit 1
else
    echo -e "${LGREEN}OK${GREY}"
    echo
fi

# Symlink from sites-available to sites-enabled
ln -s /etc/nginx/sites-available/$PROXY_SITE /etc/nginx/sites-enabled/

# Make sure default Nginx site is unlinked
unlink /etc/nginx/sites-enabled/default

# Do mandatory Nginx tweaks for logging actual client IPs through a proxy IP of 127.0.0.1 - DO NOT CHANGE COMMAND FORMATING!
echo -e "${GREY}Configuring Apache Tomcat valve for pass through of client IPs to Guacamole logs...${GREY}"
sudo sed -i '/pattern="%h %l %u %t &quot;%r&quot; %s %b"/a        \        <!-- Allow host IP to pass through to guacamole.-->\n        <Valve className="org.apache.catalina.valves.RemoteIpValve"\n               internalProxies="127\.0\.0\.1|0:0:0:0:0:0:0:1"\n               remoteIpHeader="x-forwarded-for"\n               remoteIpProxiesHeader="x-forwarded-by"\n               protocolHeader="x-forwarded-proto" />' /etc/$TOMCAT_VERSION/server.xml
if [ $? -ne 0 ]; then
    echo -e "${LRED}Failed. See ${LOG_LOCATION}${GREY}" 1>&2
    exit 1
else
    echo -e "${LGREEN}OK${GREY}"
    echo
fi

# Allow large file transfers through Nginx
sudo sed -i '/client_max_body_size/d' /etc/nginx/nginx.conf                                     # remove this line if it already exists to prevent duplicates
sudo sed -i "/Basic Settings/a \        client_max_body_size 100000000M;" /etc/nginx/nginx.conf # Add the larger file transfer size
echo -e "${GREY}Boosting Nginx's 'maximum body size' parameter to allow large file transfers...${GREY}"
if [ $? -ne 0 ]; then
    echo -e "${LRED}Failed. See ${LOG_LOCATION}${GREY}" 1>&2
    exit 1
else
    echo -e "${LGREEN}OK${GREY}"
    echo
fi

# Bind guacd to localhost and force all Guacamole connections via reverse proxy
echo -e "${GREY}Binding guacd to 127.0.0.1 port 4822..."
cp /etc/guacamole/guacd.conf /etc/guacamole/guacd.conf.bak
cat >/etc/guacamole/guacd.conf <<-"EOF"
[server]
bind_host = 127.0.0.1
bind_port = 4822
EOF
if [ $? -ne 0 ]; then
    echo -e "${LRED}Failed. See ${LOG_LOCATION}${GREY}" 1>&2
    exit 1
else
    echo -e "${LGREEN}OK${GREY}"
    echo
fi

# Update general ufw rules so force traffic via reverse proxy. Only Nginx and SSH will be available over the network.
echo -e "${GREY}Updating firewall rules to allow only SSH and tcp 80/443..."
sudo ufw default allow outgoing >/dev/null 2>&1
sudo ufw default deny incoming >/dev/null 2>&1
sudo ufw allow OpenSSH >/dev/null 2>&1
sudo ufw allow 80/tcp >/dev/null 2>&1
echo "y" | sudo ufw enable >/dev/null 2>&1
if [ $? -ne 0 ]; then
    echo -e "${LRED}Failed. See ${LOG_LOCATION}${GREY}" 1>&2
    exit 1
else
    echo -e "${LGREEN}OK${GREY}"
    echo
fi

# Reload everything
echo -e "${GREY}Restaring Guacamole & Ngnix..."
sudo systemctl restart $TOMCAT_VERSION
sudo systemctl restart guacd
sudo systemctl restart nginx
if [ $? -ne 0 ]; then
    echo -e "${LRED}Failed. See ${LOG_LOCATION}${GREY}" 1>&2
    exit 1
else
    echo -e "${LGREEN}OK${GREY}"
fi

# Done
echo -e ${NC}