patch discord's apks utility

patch_apk.sh

#!/bin/bash

# utility script made by @wavedevgit

# patch apk to own api
# this works with all clients
# make sure you put correct config here

API_URL="http://localhost:3001" # this is for api + ws, do not add version, only base url
CDN_URL="http://localhost:3001"
API_HOST="localhost:3001" # Used for ws


### colors ###
YELLOW='\033[1;33m'
GREEN='\033[1;32m'
RESET='\033[0m'


echo -e using ${GREEN}api url${RESET}=${YELLOW}$API_URL, ${GREEN}cdn url${RESET}=${YELLOW}$CDN_URL
check_tool() {
    local tool=$1
    if command -v "$tool" >/dev/null; then
        echo "$tool exists"
    else
        echo "ERROR: $tool missing, please download it!"
        exit 1
    fi
 }
check_required_tools() {
    echo -e "${YELLOW}----tools----${RESET}"
    check_tool "apktool"
    check_tool "zipalign"
    check_tool "apksigner"
    echo -e "${YELLOW}-------------${RESET}"
}

generate_key() {
  keytool -genkeypair \
    -keystore debug.keystore \
    -alias whatever \
    -keyalg RSA \
    -keysize 2048 \
    -validity 10000 \
    -storepass password \
    -keypass password \
    -dname "CN=Android,O=Android,C=US"
}

## check tools before doing anything
check_required_tools

if [ ! -f "$1" ]; then
    echo "file: \"$1\" doesn't exist."
    exit 1
fi


echo -e ${YELLOW}decompiling apk using apktool${RESET}
apktool d $1 -f -o "$1"_decompiled
cd "$1"_decompiled


### MODIFY CDN URL ###

find . -type f -name "*.smali" -exec sed -i "s|https://cdn.discordapp.com|$CDN_URL|g" {} +


### MODIFY API URL ###

find . -type f -name "*.smali" -exec sed -i "s|https://discordapp.com|$API_URL|g" {} +
find . -type f -name "*.smali" -exec sed -i "s|https://discord.com|$API_URL|g" {} +
find . -type f -name "*.smali" -exec sed -i "s|discord.com|$API_HOST|g" {} +
find . -type f -name "*.smali" -exec sed -i "s|discordapp.com|$API_HOST|g" {} +

echo -e ${GREEN}Patched smali files, building and signing${RESET}

apktool b
cd dist
### ALIGN ZIP ###
echo -e ${YELLOW}ZIPAligning apk${RESET}
zipalign -p 4 *.apk app-aligned.apk

### GENERATE KEY ###
generate_key
echo -e ${GREEN}generated debug key at debug.keystore${RESET}

### SIGN APK ###

echo -e ${YELLOW}signing apk${RESET}
apksigner sign \
  --ks debug.keystore \
  --ks-key-alias whatever \
  --ks-pass pass:password \
  --key-pass pass:password \
  --out patched-signed.apk \
  app-aligned.apk
apksigner verify --verbose patched-signed.apk
cp ./patched-signed.apk ../../patched-signed.apk
echo -e ${YELLOW}Done patching, apk is saved to patched-signed.apk
echo -e HAVE FUN!