download latest signal APK

update-signal-apk.sh

#!/bin/bash
set -e

yaml2json() {
  python3 -c 'import json, sys, yaml; json.dump(yaml.safe_load(sys.stdin), sys.stdout)'
}

json="$( curl https://updates.signal.org/android/latest.json )"
meta=org.thoughtcrime.securesms.yml

cur_vsn="$( yaml2json < "$meta" | jq -r .CurrentVersionCode )"
lat_vsn="$( printf '%s' "$json" | jq -r .versionCode )"
lat_url="$( printf '%s' "$json" | jq -r .url )"
lat_sha="$( printf '%s' "$json" | jq -r .sha256sum )"

echo "current versionCode: $cur_vsn"
echo "latest  versionCode: $lat_vsn"

file="${lat_url##*/}"
if [ ! -e "$file" ]; then
  vsn="$( printf '%s' "$json" | jq -r .versionName | tr -cd 0-9. )"
  if [ "$file" != "Signal-Android-website-prod-universal-release-$vsn.apk" ]; then
    echo "unexpected file name: $file" >&2
    exit 1
  fi
  echo "downloading $file..."
  wget -O "$file" -- "$lat_url"
  printf '%s  %s' "$lat_sha" "$file" | sha256sum -c
fi