megafetch.sh

#!/bin/bash

# Based on community mega URL parser scripts used by MapleLegends Linux installers.
# Input : MEGA file URL
# Output:
#   line1 = direct download URL
#   line2 = file name
#   line3 = AES key (hex)
#   line4 = IV (hex)

set -euo pipefail

URL="${1:-}"

if [[ ! "$URL" =~ ^https?://mega(\.co)?\.nz ]]; then
    echo "Usage: ${0##*/} <mega-url>" >&2
    exit 1
fi

command -v curl >/dev/null 2>&1 || { echo "curl not found" >&2; exit 1; }
command -v openssl >/dev/null 2>&1 || { echo "openssl not found" >&2; exit 1; }

# Parse ID / key from both old and new MEGA URL patterns.
if [[ "$URL" =~ .*/file/[^#]*#[^#]* ]]; then
    id="${URL#*file/}"
    id="${id%%#*}"
    key="${URL##*file/}"
    key="${key##*#}"
else
    id="${URL#*!}"
    id="${id%%!*}"
    key="${URL##*!}"
fi

raw_hex=$(
    echo "${key}=" | tr '\-_' '+/' | tr -d ',' | base64 -d -i 2>/dev/null \
        | od -v -An -t x1 | tr -d '\n '
)

hex=$(printf "%016x%016x" \
    $((0x${raw_hex:0:16} ^ 0x${raw_hex:32:16})) \
    $((0x${raw_hex:16:16} ^ 0x${raw_hex:48:16}))
)

json=$(curl -s -H 'Content-Type: application/json' \
    -d '[{"a":"g", "g":"1", "p":"'"$id"'"}]' \
    'https://g.api.mega.co.nz/cs?id=&ak=')
json="${json#"[{"}"
json="${json%"}]"}"
file_url="${json##*'"g":'}"
file_url="${file_url%%,*}"
file_url="${file_url//'"'/}"

json=$(curl -s -H 'Content-Type: application/json' \
    -d '[{"a":"g", "p":"'"$id"'"}]' \
    'https://g.api.mega.co.nz/cs?id=&ak=')
at="${json##*'"at":'}"
at="${at%%,*}"
at="${at//'"'/}"

meta=$(
    echo "${at}==" | tr '\-_' '+/' | tr -d ',' \
        | openssl enc -a -A -d -aes-128-cbc -K "$hex" -iv "00000000000000000000000000000000" -nopad \
        | tr -d '\0'
)
meta="${meta#"MEGA{"}"
meta="${meta%"}"}"
file_name="${meta##*'"n":'}"
if [[ "$file_name" == *,* ]]; then
    file_name="${file_name%%,*}"
fi
file_name="${file_name//'"'/}"

echo "$file_url"
echo "$file_name"
echo "$hex"
echo "${raw_hex:32:16}0000000000000000"