get-eth-balance-of-at.sh

#!/bin/bash

# queries the balance (of native coins, e.g. ETH) of a given account at a given block
# requires an archive node if the block lies more than a couple of blocks in the past
#
# Requirements: python, jq, curl and awk installed and in PATH
#
# usage: get-eth-balance-of-at.sh <ethereum_address> [block_number]"
#   env var RPC must be set

set -x

if [ -z "$1" ]; then
    echo "Usage: $0 <ethereum_address> [block_number]"
    exit 1
fi

if [ -z "$RPC" ]; then
    echo "Please set the RPC environment variable to the JSON-RPC endpoint URL."
    exit 1
fi

ETH_ADDRESS="$1"
# TODO: this is ugly, fix!
BLOCKNR=${2:-"latest"}
if [ "$BLOCKNR" != "latest" ]; then
    BLOCKNR_HEX="0x$(printf '%x' $BLOCKNR)"
else
    BLOCKNR_HEX="latest"
fi

ETH_BALANCE_JSON='{"jsonrpc":"2.0","method":"eth_getBalance","params":["'$ETH_ADDRESS'", "'$BLOCKNR_HEX'"],"id":1}'
echo "ETH_BALANCE_JSON $ETH_BALANCE_JSON"

if [[ $ETH_BALANCHE_JSON == null ]]; then
    echo "failed"
    exit 1
fi

ETH_BALANCE_WEI=$(curl -s -f -X POST -H "Content-Type: application/json" --data "$ETH_BALANCE_JSON" $RPC | jq -r .result)

ETH_BALANCE=$(echo "$ETH_BALANCE_WEI" | awk '{ printf "%.18f", $1 / (10^18) }')

if [ "$BLOCKNR" != "latest" ]; then
    BLOCK_TIMESTAMP_JSON='{"jsonrpc":"2.0","method":"eth_getBlockByNumber","params":["'$BLOCKNR_HEX'", false],"id":1}'
    BLOCK_TIMESTAMP_HEX=$(curl -s -X POST -H "Content-Type: application/json" --data "$BLOCK_TIMESTAMP_JSON" $RPC | jq -r .result.timestamp)
    BLOCK_TIMESTAMP=$(python -c "import sys; print(int(sys.argv[1], 16))" "${BLOCK_TIMESTAMP_HEX:2}")
#    BLOCK_TIMESTAMP=$(echo "ibase=16; ${BLOCK_TIMESTAMP_HEX:2}" | bc)
    HUMAN_READABLE_TIMESTAMP=$(date -u -d @${BLOCK_TIMESTAMP} +'%Y-%m-%d %H:%M:%S')

    echo "Ethereum Balance for $ETH_ADDRESS at block $BLOCKNR (timestamp: $HUMAN_READABLE_TIMESTAMP): $ETH_BALANCE ETH"
else
    echo "Ethereum Balance for $ETH_ADDRESS: $ETH_BALANCE ETH"
fi