Mediachain an open, universal media library

Mediachain

• About Mediachain

Installation and Setup

• Installing Mediachain
• Using Mediachain Deploy
• Linking Your Identity
• Getting Started
• Configuring NAT Traversal
• Controlling a remote node with SSH Tunneling

Using Mediachain

• Basic Operations
• Pushing Data to Remote Peers
• Advanced Operations

Publishing Data

• Schema Generation With schema-guru
• Schema Recommendations

Tutorials

• Ingesting Museum Data (MoMA)
• Ingesting Museum Data (Cooper Hewitt)

Mediachain Architecture

• Statements and Objects
• Glossary
• MCQL

• Starting a new node
• Bringing the node online
  • Configuring the directory
• Taking the node online
• Next steps

Welcome to Mediachain! This guide will help you get started with a newly-installed mediachain node. For help with installation, please check out the Installation Guide, then come back here.

This guide will assume that you’ve installed mcnode and mcclient on your local computer, and you want to get your node ready to use. If you’ve deployed your node to the cloud, everything will work just the same, but you’ll need to set up an SSH tunnel to control your node.

Starting a new node

Let’s start our node!

You can run your local mediachain node by invoking mcnode without arguments:

$ mcnode
2016/10/20 19:29:24 Generating new node identity
2016/10/20 19:29:25 Saving key to /home/vyzo/.mediachain/mcnode/identity.node
2016/10/20 19:29:25 Node ID: QmeBkfxcaBfA9pvzivRwhF2PM7sXpp4HHQbp7jfTkRCWEa
2016/10/20 19:29:25 Generating new publisher identity
2016/10/20 19:29:25 Saving key to /home/vyzo/.mediachain/mcnode/identity.publisher
2016/10/20 19:29:25 Publisher ID: 4XTTMADSKQUN3jkeZngbtuE35w9y5YnDTicVTeeji7N2Npkey
2016/10/20 19:29:25 Node is offline
2016/10/20 19:29:25 Serving client interface at 127.0.0.1:9002

The first time you run mcnode, it will generate a pair of persistent identities and initialize the local store. By default, mcnode uses ~/.mediachain/mcnode as its root directory, but you can change this using the -d path/to/mcnode/home command line option.

Bringing the node online

By default, the node starts disconnected from the p2p network and provides a client control api in localhost. You can control and use your node through the api using curl, but it is recommended to install Aleph. Aleph provides a fully featured client for mcnode named mcclient and we use it in the examples below.

Once your node is up and running you can check its status:

$ mcclient id
Peer ID: QmeBkfxcaBfA9pvzivRwhF2PM7sXpp4HHQbp7jfTkRCWEa
Publisher ID: 4XTTMADSKQUN3jkeZngbtuE35w9y5YnDTicVTeeji7N2Npkey
Info:
$ mcclient status
offline

Since our status is offline, we can’t reach other peers, and attempting to do so will result in an error:

$ mcclient listPeers
Internal Server Error
Error: Node is offline

Let’s fix that by setting a directory server and taking our node online.

Configuring the directory

At this point you should designate a directory for looking up peers. We’ll use the multiaddress of the Mediachain Labs public directory, /ip4/52.7.126.237/tcp/9000/p2p/QmSdJVceFki4rDbcSrW7JTJZgU9so25Ko7oKHE97mGmkU6.

$ mcclient config dir /ip4/52.7.126.237/tcp/9000/p2p/QmSdJVceFki4rDbcSrW7JTJZgU9so25Ko7oKHE97mGmkU6
set directory to /ip4/52.7.126.237/tcp/9000/p2p/QmSdJVceFki4rDbcSrW7JTJZgU9so25Ko7oKHE97mGmkU6

The directory allows you to contact other nodes that have registered themselves by setting their status to public. When contacting a remote node, we use their Peer ID, which is an encoded multihash that’s derived from the node’s public key. The directory maps Peer IDs to routable addresses that our node can use to connect to others.

Setting the directory does not make your node visible to others; for that we need to set our status to public. We’ll do that in a little while; first lets take our node online so that it can query the directory and contact other peers.

Taking the node online

Set the node’s status to online:

$ mcclient status online
status set to online

Now we can query the directory for the list of registered peers:

$ mcclient listPeers
...
QmeiY2eHMwK92Zt6X4kUUC3MsjMmVb2VnGZ17DhnhRPCEQ
...

And learn more about them:

$ mcclient id QmeiY2eHMwK92Zt6X4kUUC3MsjMmVb2VnGZ17DhnhRPCEQ
Peer ID: QmeiY2eHMwK92Zt6X4kUUC3MsjMmVb2VnGZ17DhnhRPCEQ
Publisher ID: 4XTTM4K8sqTb7xYviJJcRDJ5W6TpQxMoJ7GtBstTALgh5wzGm
Info: Metadata for CC images from DPLA, 500px, and pexels; operated by Mediachain Labs.

We can also get the Info string alongside the directory listing with mcclient listPeers --info:

$ mcclient listPeers --info
QmTVsocFCSEdPyM8dZ734GRhjvvmYyL9fShyezVkbPj17E -- Curated Museum Metadata; Operated by Mediachain Labs
QmeiY2eHMwK92Zt6X4kUUC3MsjMmVb2VnGZ17DhnhRPCEQ -- Metadata for CC images from DPLA, 500px, and pexels; operated by Mediachain Labs.
QmZ6dckUhRouVr6AsBTpK6vMLVpcz1KAeJAJVQEZQ5gCek -- Metadata for CC images from flickr; operated by Mediachain Labs.
...

Next steps

See the Basic Operations guide to learn how to query, publish data, merge remote data and make your node publicly accessible.