Bitcoin proxy server

An http server with a single POST /proxy endpoint that sends RPC methods and params to bitcoin core.

By default we restrict to a short whitelist of allowed methods that core lightning needs:

  - echo
  - estimatesmartfee
  - getblock
  - getblockhash
  - getblockchaininfo
  - getnetworkinfo

Setup

git clone https://github.com/coinos/bps
cd bps
npm i

cp .env.sample .env and edit accordingly:

RPCUSER=admin1
RPCPASS=123
RPCWALLET=coinos
RPCHOST=localhost
RPCPORT=18443

Then

npm start

Extra

Here's a bash script to get c-lightning to call https://coinos.io/proxy instead of its native bitcoin-cli:

#!/bin/bash

# inspired by https://github.com/lightningd/plugins/issues/112#issuecomment-818536220

ARGS=$(echo $* | sed 's/-[^ ]\+ //')
OPTS=$(echo $* | tr ' ' '\n' | grep '^-')
shift $(echo $OPTS | wc -w)
ARGN=$(echo $ARGS | wc -w)

join_by() {
  local d=${1-} f=${2-}
  if shift 2; then
    printf %s "$f" "${@/#/$d}"
  fi
}

method=\"$1\"
shift

if test "$ARGN" = 1; then
  params=[]
else
  params="[\"$(join_by "\",\"" $@)\"]"
fi

curl -s -f https://coinos.io/proxy -H "content-type: application/json" -d '{ "method": '$method', "params": '$params' }'

if test $? = 22; then
  exit 8
fi

Copy the script to .lightning/bitcoin-cli and edit .lightning/config to add the bitcoin-cli option:

bitcoin-cli=/root/.lightning/bitcoin-cli

Note: You'll need to have curl available. The official c-lightning docker image doesn't include it but it's easy enough to add. Just make a new Dockerfile:

FROM elementsproject/lightningd:v22.11.1
RUN apt update
RUN apt install curl -y

And build it with docker build . -t lightning