Coinfloor Python Client

An Python class, together with a "driver" code, meant as an example of making authenticated calls to Coinfloor's WebSocket API.

Prerequisites

• Python 3 interpreter, together with the "devel" counterpart
• gmp GNU Multi Precision Arithmetic Library, together with the "devel" counterpart
• pip3 package manager
• ecdsa library for creating Elliptic Curve signatures
• websocket-client library for WebSocket support

Preparation

In major Linux distributions, packages Python 3 and pip3 either are already installed, or can be installed using the distribution-specific package manager. Package pip works only with Python 2, to install pip packages for Python 3, pip3 tool needs to be used. On Windows, pip3 package manager comes installed as a part of the standard Python 3 release. The client also imports the following: base64, hashlib, json, random, ssl, threading, time. All of these; however, come together with a Python 3 installation, and are merely enumerated here.

To install websocket-client and ecdsa libraries, run

pip3 install [--user] websocket-client ecdsa

with appropriate privileges.

After the above dependencies have been meet, the client is ready to run.

Executing

Executing

[<path>/]clientExample.py -h

will give the list of arguments, together with their up to date description

Details

The main part of the client is a WSClient class, which is initalised with the WebSocket endpoint's URL (obligatory) and the optional event hooks:

msg_handler
err_handler    (default action: raise a 'ConnectionError')
open_handler
close_handler
ping_handler
pong_handler
insecure_ssl
socket_timeout (default value: 5 seconds)

Connecting and authenticating are done in a lazy manner, i.e. the connection is being made only when data need to be sent, and authentication data are sent the first time non-public method is being called. Upon the first method being called, after the connection and/or authentication have been established, the client starts the "event" thread which monitors messages coming in from the server and handles them accordingly (which normally involves passing them to the msg_handler). At the same time, the same instance of the WSClient class may be used to call remote WebSocket methods. By default, only in two cases:

• the connection is being established, and
• the authentication is being attempted

is the WSClient instance thread-safe (that is, the sending thread will block and wait for the connecting/authenticating sequence to complete before allowing any further calls).

The client also defines an Assets dictionary, which contains mappings between asset names and their codes.