joinmarket-clientserver

Joinmarket refactored to separate client and backend operations

Motivation: By separating the code which manages conversation with other Joinmarket participants from the code which manages this participant's Bitcoin wallet actions, we get a considerable gain at a minor cost of an additional layer: code dependencies for each part are much reduced, security requirements of the server/daemon layer are massively reduced (which can have several advantages such as it being more acceptable to distribute this layer as a binary), and client code can be written, implementing application-level logic (do join with coins X under condition X) using other Bitcoin libraries, or wallets, without knowing anything about Joinmarket's inter-participant protocol. An example is my work on the Joinmarket electrum plugin.

It also means that updates to the Bitcoin element of Joinmarket, such as P2SH and segwit, should have extremely minimal to no impact on the backend code, since the latter just implements communication of a set of formatted messages, and allows the client to decide on their validity beyond simply syntax.

Joinmarket's own [messaging protocol] is thus enforced only in the server/daemon.

The client and server currently communicate using twisted.protocol.amp, see AMP which is a very clean asynchronous messaging protocol, and the specification of the communication between the client and server is isolated to this module.

The server is currently implemented as a daemon (see scripts/joinmarketd.py), in future it may be convenient to create the option to run it within the same process as the client.

Use virtualenv to manage dependencies, e.g. follow this workflow:

git clone https://github.com/AdamISZ/joinmarket-clientserver
cd joinmarket-clientserver
virtualenv .
source bin/activate

Next, you can install in 3 different modes:

1. For the "backend", a daemon, install:

   python setupall.py --daemon

Then, you can run the daemon with cd scripts; python joinmarketd.py <port number>

2. For the client code, using joinmarket's own bitcoin library on the command line:

   python setupall.py --client-bitcoin

If you have installed this "full" version of the client, you can use it with the command line scripts as explained in the scripts README.

3. For the client code, using another bitcoin backend library (currently only Electrum supported, see https://github.com/AdamISZ/electrum-joinmarket-plugin for details):

   python setupall.py --client-only

You can then access the library via import jmclient. In particular the jmclient.Taker class must be instantiated.

Test instructions and test scripts: todo.