Validate htaccess based on https://github.com/liquidweb/htaccess-validator/issues/5

validate-htaccess.sh

#!/usr/bin/env bash
#
# This script injects a file into the current Apache2 environment temporarily
# in order to check its syntax.
#
# INSTALL:
#     sed -i "2i  ServerName example.com" /etc/apache2/sites-available/000-default.conf
#     Require adding this line to the example conf
#
# USAGE:
#     validate-htaccess <file|stdin> [-u example.com]
#
# EXAMPLE:
#     validate-htaccess [/path/to/.htaccess][stdin] [-u (domain from apache setting)]
#
# EXIT CODES:
#
# 0 - The syntax is valid.
# 1 - The syntax is invalid, see STDERR for details.
# 2 - The httpd binary could not be found.
# 3 - No parameters are used.
#
# Author: Liquid Web & Daniele Scasciafratte
# License: MIT

# If parameter is used or stdin
if [ "$#" == 0 ]; then
    file=$(mktemp)
    sleep 1
    if read -r -t 0; then
        cat > tee "$file"
    else
        echo "No parameters or stdin, closed."
        exit 3
    fi
else
    file=${1:?No configuration file specified.}
fi

APACHE_DOMAIN="example.com"

while getopts u: option
do
    case "${option}"
    in
        u) APACHE_DOMAIN=${OPTARG};;
        *) echo '';;
    esac
done

# Ensure the file can be loaded.
tmpfile=$(mktemp)
cat "$file" > "$tmpfile"
sed --in-place '/RewriteBase/d' "$tmpfile"

# Ensure that httpd is available.
if [[ ! $(command -v httpd) && ! $(command -v apache2ctl) ]]; then
    echo 'Unable to find the httpd binary or apache2ctl script, is Apache2 installed?' 1>&2
    exit 2
fi

command -v httpd &> /dev/null
exit_code=$?

if [ $exit_code -eq 0 ]; then
    httpd="httpd"
fi;

command -v apache2ctl &> /dev/null
exit_code=$?

if [ $exit_code -eq 0 ]; then
    httpd="apache2ctl"
fi;

# Get the name of the current configuration file.
current_config=$(${httpd} -V \
    | grep -E -o -e 'SERVER_CONFIG_FILE="(.+)"' \
    | sed 's/SERVER_CONFIG_FILE=//; s/"//g')

# Now, use Apache to validate itself, injecting $FILE into the current
# server environment.
results=$(${httpd} -t -C "Include ${current_config}" -f "$tmpfile" -C "ServerName ${APACHE_DOMAIN}" 2>&1)
exit_code=$?

# Remove the temp file.
rm "$tmpfile"

# If the check passed, there's nothing more to do.
if [ $exit_code -eq 0 ]; then
    exit
fi

# Something went wrong, so we need to parse the results.
tmpfilename=${tmpfile##*/}
echo "$results" | sed -E 's/^.+'"$tmpfilename"': //' 1>&2
exit 1