@futuretense/stellar-pathfinder-server

What?

Listen to anyone talking about Stellar and what sets it apart from other blockchain projects, and path payments will ultimately be touted.

The ability to pay for a cup of coffee using whatever asset you have at hand, and still have the merchant receive their preferred currency. Commerce, cross-border remittances; the uses are many.

Path finding is at the center of this.

To do a path payment you need to supply a path to the network, to get a path you need to ask someone to figure one out for you.

By default, this is one of the responsibilities of a Horizon server.

This is a standalone path finding server that performs path finding without the need to have a Horizon server running.

Why?

For the vision to come true of everyday use of path payments, for every payment, path finding has to be able to run at interactive rates. You don't want to leave users hanging, waiting around wondering what's going on.

Looking at the current stats, that's exactly what happens now, which is what led to the development of this project.

	stellar.org	satoshipay.io	pathfinder
Get account status ¹	0.300s	0.353s	N/A
Find path ²	5.340s	6.647s	0.586s

How?

Requirements

A synced stellar-core node
A PostgreSQL instance w/ a stellar-core database

Installing

From the NPM package

npm install -g @futuretense/stellar-pathfinder-server

From the source code

git clone https://github.com/future-tense/stellar-pathfinder-server.git
cd stellar-pathfinder-server
npm install
npm run build
npm install -g

These will install the command-line tool stellar-pathfinder-server, which can be run, with the proper environment variables set.

Environment variables

STELLAR_CORE_DB
- PostgreSQL connection string, e.g.
  - postgres://{username}:{password}@{host}:{port}/{database}
API_PORT
- TCP port to listen to for incoming connections for the API. Default: 8000
TRIGGER_DELAY
- How many milliseconds after the last trigger to wait before considering a ledger complete. Default: 5
LOG_LEVEL
- NONE, FATAL, ERROR, WARN, INFO, DEBUG, TRACE/ALL. Default: INFO

Compatibility with Horizon

The REST API is more-or-less compatible with the Horizon API, and could be used as a drop-in replacement simply by remapping the "/paths" path on the server that runs Horizon.

The differences are

pathfinder requires the source_account query parameter
pathfinder ignores the destination_account query parameter
pathfinder returns fewer results

Notes:

1) using the median value of three runs of time curl https://{host}/accounts/GDUMWJ3ISSVBKGZHVQZRVUN6TUOJETXDV7POKVNXEYBCRN4CQOYCV5AA

2) using the median value of three runs of time curl "https://{host}/paths?source_account=GDUMWJ3ISSVBKGZHVQZRVUN6TUOJETXDV7POKVNXEYBCRN4CQOYCV5AA&destination_account=GDUMWJ3ISSVBKGZHVQZRVUN6TUOJETXDV7POKVNXEYBCRN4CQOYCV5AA&destination_asset_type=credit_alphanum4&destination_asset_code=BTC&destination_asset_issuer=GBSTRH4QOTWNSVA6E4HFERETX4ZLSR3CIUBLK7AXYII277PFJC4BBYOG&destination_amount=0.01"