aleph

א

The Aleph's diameter was probably little more than an inch, but all space was there, actual and undiminished. Each thing (a mirror's face, let us say) was infinite things, since I distinctly saw it from every angle of the universe¹

Aleph is part of the mediachain project and is an integral component of the Phase II architecture.

Aleph provides two main components. First is a client for the HTTP API exposed by concat, the reference go peer implementation. Second is a lightweight peer in its own right.

Installation

Aleph requires node 6 or greater, and has primarily been tested with 6.5 and above.

To globally install a release from npm: npm install --global aleph. This will install the mcclient command, which you can use to control and interact with a concat node.

If you'd prefer to install from the source repository, clone this repo and run npm install, followed by npm link, which will create an mcclient symlink that runs the latest compiled version of the code. This is very useful during development.

If you don't want mcclient on your path at all, you can just run npm install and execute ./bin/mcclient.js directly instead.

Usage

mcclient is a wrapper around the HTTP API exposed by concat, aleph's heavy-lifting counterpart.

mcclient contains several sub-commands, so the general invocation is mcclient [global-options] <command> [command-options].

At the moment, the only global option is --apiUrl or -p, which sets the location of the remote node's HTTP API. By default, mcclient will attempt to connect to a concat node running on localhost at port 9002, which is concat's default listen address for the HTTP API. If you've configured concat to run on a different port or on a remote machine, use the -p flag to pass in a new URL, e.g. mcclient -p http://localhost:5678 id

Some useful commands include:

• id: print the node's peer id and publisher id
• status:
  • with no arguments, prints the current status (online, offline, or public)
  • set the status with e.g. mcclient status online
• publish: publish JSON metadata to the node's local store. see mcclient publish --help for more info.
• statement: retrieve a statement by its id
• query: run a mediachain query against the node's local store.

To see a full list of supported commands, run mcclient --help

Development and contribution

Thanks! We welcome all contributions of ideas, bug reports, code, and whatever else you'd like to send our way. Please take a look at our contributing guidelines -- they are very friendly.

Code structure

The code lives in src, and is organized into a few main subdirectories:

• client/api contains the RestClient class, which provides a Promise-based wrapper around concat's HTTP API
• client/cli contains the code for the mcclient command line app, which uses RestClient for all of its functionality. The cli is powered by the yargs argument parser, and each subcommand is contained in its own module in client/cli/commands
• peer contains the javascript implementation of mediachain peer-to-peer nodes. There are two main node types, a DirectoryNode that corresponds to concat's mcdir command, and a MediachainNode that corresponds to concat's mcnode. Both use the LibP2PNode class (defined in src/peer/libp2p_node.js) for low-level peer-to-peer networking.
• protobuf contains protocol-buffer definitions for messages exchanged between nodes, and is kept in sync with concat.